L Titel E - · PDF fileManufacturing printing rollers on an MFP traverse table machine ......

KNOW-HOW: SCHLEIFRING Group innovations

BEST PRACTICE: Presentations by highly respected experts

Grinding in motionSpecial edition: SCHLEIFRING Grinding Symposium 2009

THE CUSTOMER MAGAZINE OF THE SCHLEIFRING GROUP

I S S U E 1 / 2 0 0 9

MOTION

L_Titel_E.indd 1 09.04.2009 13:53:26 Uhr

www.winterthurtechnology.com

PROFILE GRINDING WITH WINTERTHUR: PASSIONATELY PRECISE

SwitzerlandWinterthur Schleiftechnik AGOberer Deutweg 4 8411 WinterthurTel.: +41 (0)52 234 41 41Fax: +41 (0)52 232 51 [email protected]

GermanyWENDT GmbHFritz-Wendt-Strasse 140670 MeerbuschTel.: +49 (0)2159 671-0Fax: +49 (0)2159 806 [email protected]

USAWinterthur Corporation10 Viking RoadWebster MA 01570Tel.: +1 (508) 949 10 61Fax: +1 (508) 949 20 [email protected]

AustriaRappold Winterthur Technologie GmbHSt. Magdalenerstrasse 859500 VillachTel.: +43 (0)42 42 41 811 0Fax: +43 (0)42 42 41 811 [email protected]

United KingdomWinterthur Technology UK Ltd.2 Oakham Drive Parkwood Industrial EstateSheffield S3 9QXTel.: +44 (0)114 275 42 11Fax: +44 (0)114 275 41 [email protected]

SwedenSlipNaxos ABFolksparksv. 3159383 VästervikTel.: +46 (0)490 843 00Fax: +46 (0)490 146 [email protected]

GermanyWinterthur Schleiftechnik GmbHHundsschleestrasse 1072766 ReutlingenTel.: +49 (0)7121 93 24 0Fax: +49 (0)7121 93 24 [email protected]

L_Editorial_E.indd 2 09.04.2009 13:55:43 Uhr

E D I TO R I A L

Yours sincerely

Dr Ralf Kammermeier

Managing Director

Körber Schleifring GmbH

rely

mmermeier

Director

eifring GmbH

3MOTION 01/09

Technologies for the future

Dear Readers,

The economic and fi nancial crisis has the world on tenterhooks. Even key sectors,

like the automotive, aircraft and machine construction industries, are severely

affected by the changes. Lots of people are asking: When will we emerge from the

crisis and how? And what will the future bring? Yet times of economic diffi culty

also present opportunities. Firms that set the right objectives now will be in a good

position after the recession. Experts are sure that with expertise and cutting-edge

technology we can face the future with optimism.

The SCHLEIFRING Group is therefore aiming for technological leadership in all areas

of fi ne machining. See for yourself at the SCHLEIFRING Grinding Symposium 2009.

We will be demonstrating our latest products and developments live at 17 stations,

from solutions designed to increase productivity and quality to effi cient software

tools and fully developed measuring technology. The demonstra-

tions will be supported by presentations given by leading

industry experts. Their talks will provide insights into the

latest research fi ndings.

This special edition of MOTION brings together the key

information. You can look forward to a varied mix of

scientifi c research and practical application. We hope

you enjoy reading this issue of MOTION.

L_Editorial_E.indd 3 09.04.2009 13:55:44 Uhr

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Cylindrical grinding

Station 4 – STUDERmodular

From heavy-duty applications to

fl exible production – the S22 leaves

nothing to be desired

Station 5 – STUDERmicro

Precise, productive and reliable – the

manufacture of small and micro parts

on the S21 and S12

Station 6 – STUDERinternal

Flexible manufacture in small batch

and large batch production

Station 8 – MIKROSA

Complete machining: High-speed

grinding of jet needles on the

MIKROSA KRONOS S

Station 9 – SCHAUDT ShaftGrind S

Machining of drive shafts with

swivel-in spindle technology

Station 10 – SCHAUDT CamGrind L2

With swivel-in spindle technology

camshafts are machined complete in

one clamping

Station 11 – STUDERfl exible

The STUDER S242 with three

cross-slides is the most fl exible

hard fi ne machining center

Station 12 – STUDERintelligent

StuderTechnology optimizes the

grinding processes on the S 31 and

S33 by up to 50 per cent

Surface grinding

Station 1 – MÄGERLE

Optimum surface quality and accuracy.

Manufacturing printing rollers on an

MFP traverse table machine

Station 2 – BLOHM JUNG

Forward-looking surface and profi le

grinding with modern control and

machining systems

Station 3 – BLOHM JUNG GEOID

The effi ciency of diamond wear

compensation using high-perfor-

mance blanking punches

Service

Station 7 – SERVICE Quality

Systematic servicing carried out

by SCHLEIFRING Service optimizes

machine availability

Tool grinding

Station 13 – EWAG COMPACT LINE

The EWAG COMPACT LINE is

designed for the fl exible manufacture

of all types of inserts

Station 14 – EWAG EWAMATIC LINE

Fully automated machining of

PCD/PCBN equipped highly complex

round tools

Station 15 – WALTER

HELITRONIC MICRO and HELICHECK

PLUS – the high-performance double

act for micro tools


Perfect cutting edges of PCD tools

manufactured on the HELITRONIC

POWER DIAMOND


Tapping the full potential

of tool grinding machines:

HELITRONIC ToolStudio is

the no. 1 software

TOOLS & TECH NOLOGY

CONTENTS

4 MOTION 01/09

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L_Inhalt_E.indd Abs2:4 09.04.2009 13:57:13 Uhr

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Technical Symposium I:

Innovative production

Lecture I-1 Prof. Thomas Straubhaar: The global

economy in recession: what can be done?

Lecture I-2 Prof. Eckart Uhlmann: Quo vadis

precision machining?

Lecture I-3 Dr Hans-Werner Hoffmeister:

Effective cooling and lubricating in grinding

Lecture I-4 Johann Noichl: Dressing grinding

wheels – a nice piece of work?

Technical Symposium II:

Surface and profi le grinding

Lecture II-1 Prof. Taghi Tawakoli: Advantages of ultrasonic

grinding and dressing compared to conventional grinding

and dressing

Lecture II-2 Prof. Wilhelm Schröder: Professionally

compensating for form deviations during profi le dressing

Lecture II-3 Dr Christoph Zeppenfeld: Interactions of process

and machine when surface grinding

Lecture II-4 Dr August Kästner: Effi cient grinding of

components for vane pumps and motors

Technical Symposium III:

Production cylindrical grinding

Lecture III-1 Prof. Klaus Weinert: Innovative concepts for

internal cylindrical machining

Lecture III-2 Dr Bernd Möller: New grinding spindles for

operation at extremely high rotary speeds

Lecture III-3 Harro Wörner: Global strategy of standard ma-

chines from the point of view of the large volume manufacturer

Lecture III-4 Udo Mertens: High performance grinding

wheels for external cylindrical grinding

Technical Symposium IV: Tool grinding

Lecture IV-1 Prof. Wilfried Saxler: Tool grinding –

the industry of the future

Lecture IV-2 Dr Dieter Kress: Multi-axis precision grinding

Lecture IV-3 Christoph Hübert: New methods for

the manufacture and use of micro cutting tools

Lecture IV-4 Oliver Wenke: Measuring technology

guarantees cost-effective tool production

Technical Symposium V:

Universal cylindrical grinding

Lecture V-1 Prof. Konrad Wegener: Simulation of abrasive

tools and processes

Lecture V-2 Dr Frank Fiebelkorn: Effi cient hard fi ne machining

Lecture V-3 Dr Carsten Russner: Precision grinding of brittle

hard ceramics under production conditions

Lecture V-4 Walter Graf: How do you choose the ‘ideal’

abrasive material?

MARKE TS & TR E N DS

5MOTION 01/09

IMPRINT

Publisher: Körber Schleifring GmbH, Hamburg Chief editor: Peter Lütjens Realization: JDB MEDIA GmbH, Schanzenstraße 70, 20357 Hamburg, Germany Project management:

Jan Hawerkamp Art direction: Claudia Schiersch Editorial board: Marc-Oliver Prier (dir.), Dania Müller, Ira Schroers Layout: Steffi Pfl ugbeil (Ltg.), Yvonne Vahland Proofreading, editing

and translation: SKH SprachKontor Hamburg GmbH Photos: ddp-archiv (2), F1 online (1), Getty Images (2), PR/Hersteller (142) Lithography: Fire Dept. GmbH, Hamburg Printing: NEEF +

STUMME GmbH & Co. KG, Wittingen

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CO N T E N T

L_Inhalt_E.indd Abs2:5 17.04.2009 11:27:04 Uhr

M O T I O N S & M O R E

6 MOTION 01/09

SCHLEIFRING GRINDING SYMPOSIUM 20 09

Grinding in motion

Technical symposium I, May 6, 2009, 14.00 to 17.00: The speakers on the

subject of Innovative Production are Prof. Thomas Straubhaar, Prof. Eckart

Uhlmann, Dr Hans-Werner Hoffmeister and Johann Noichl

Technical symposium II, May 7, 2009, 9.30 to 11.30: Prof. Taghi Tawakoli,

Prof. Wilhelm Schröder, Dr Christoph Zeppenfeld and Dr August Kästner are

our speakers on surface grinding and profi le grinding

Technical symposium III, May 7, 2009, 14.00 to 17.00: The subject of produc-

tion grinding and cylindrical grinding will be dealt with by Prof. Klaus

Weinert, Dr Bernd Möller, Harro Wörner and Udo Mertens

Technical symposium IV, May 8, 2009, 9.30 to 11.30: Prof. Wilfried Saxler,

Dr Dieter Kress, Christoph Hübert and Oliver Wenke are our experts on tool

grinding

Technical symposium V, May 8, 2009, 14.00 to 17.00: Visitors will hear all

about universal cylindrical grinding from Prof. Wegener, Dr Frank Fiebel-

korn, Dr Carsten Russner and Walter Graf

A relaxing end to the day

After the machine presentations and lectures the evenings will fi nish with a pro-

gram including musical highlights and exceptional performances in the Kursaal

Casino at Interlaken. This also gives all delegates another opportunity for network-

ing and exchanging ideas with colleagues.

The SCHLEIFRING Grinding Sympo-

sium 2009 is fully geared to for-

ward-looking development, effi cient

production and successful sales.

A varied program

The eight SCHLEIFRING companies will

be present on 17 stands in all where

visitors can have fi rst-hand experience

of the latest products and technical

developments. In addition, there will be

presentations that clarify technological

improvements in productivity and qual-

ity in fi nish machining and effi cient

software solutions. The machine pre-

sentations will be given in German,

English, French and Italian (see right-

hand column for details). In addition to

these practical machine presentations

there is also a theoretical program of

fi ve colloquia with a total of 20 talks

given by well-known experts in the fi eld

to round off the three days of the sym-

posium.

At the heart of things, between

the machine presentations and

the lectures, experts in the

mechanical engineering sector

can meet in front of the bar to

exchange news and views

SCHLEIFRING is showing its comprehensive services from May 6 to 8, 2009. The SCHLEIFRING Grinding Symposium will be rounded off with lectures by well-known experts in the grinding sector.

L_FreiesThema_E.indd 6 17.04.2009 10:27:47 Uhr

7MOTION 01/09

SCHLEIFRING GRINDING SYMPOSIUM 2009 – SCHEDULE OF EVENTSStation Subject

1 MÄGERLE: Optimum surfacequality and accuracy D F D I E D F D I D E

2 BLOHM JUNG Forward-looking surface and profi le grinding E D F D I E D F D I D

3 BLOHM JUNG: GEOID diamond-wear compensation I E D F D Press E D F D I

4 STUDERmodular D I E D F I D E D F D

5 STUDERmicro F D I E D D I D E D F

6 STUDERinternal D F D I E F Press I D E D

7 SERVICE Quality E D F D I D F D I D E

8 MIKROSA: High-speed grindingof jet needles I E D F D E D F D I D

9 SCHAUDT: Machining of drive shafts with swivel-in spindle technology D I E D F D E Press F D I

10 SCHAUDT: Complete machining of camshafts F D I E D I D E D F D

11 STUDERfl exible D F D I E D I D E D F

12 STUDERintelligent E D F D I F D I D E D

13 EWAG: Flexible manufacturing of inserts I E D F D D F D I Press E

14 EWAG: Machining of PCD tools D I E D F E D F D D I

15 WALTER: High-performance double act for micro tools F D I E D D E D F I D

16 WALTER: PCD tools – perfectcutting edge D F D I E I D E D F D

17 WALTER: HELITRONIC ToolStudio E D F D I D I D Press E F

9.30 10.00 10.30 11.30 14.30 15.30 16.3011.00 14.00 15.00 16.0012.00

Lunc

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eak

Overview: Using this plan (above) you can easily

fi nd your way to the various stands. The table

below shows when each machine presentation

will be given in which language

German English French Italian Press, May 6, 2009 only, otherwise in German

EN

TR

AN

CEINFO

L_FreiesThema_E.indd 7 09.04.2009 14:37:45 Uhr

8 MOTION 01/09

Opt imum sur face qual i t y

A strong worker

T O O L S & T E C H N O LO GY

The MÄGERLE hydrostatic guidance systems set standards in the matter of precision whenmachining larger components.

piece in the machine, and together with the processing forces calculates ap-

propriate corrections. In the grinding process which follows, the machine then

travels fully automatically precisely in accordance with the values given. The

Experts in evolving solutions ex-

actly tailored to the customer’s

needs – this is the specialty of the

SCHLEIFRING company MÄGERLE. In

particular when handling large com-

ponents, the hydrostatic guidance sys-

tems of the MÄGERLE machine ranges

make the highest levels of precision

possible.

Automatic compensation

At the SCHLEIFRING Grinding Sympo-

sium 2009 the Swiss company is show-

ing the ma-chining of large compo-

nents using a plate cylinder for the

printing industry as an example. The

task of grinding is precise machining

of the start and end of print line which

is longitudinally arranged on the

chrome-plated plate cylinder. High

standards are set here both for accu-

racy and for quality of the surface fi n-

ish. In components of this size and

weight (the cylinder measures 500 mil-

limeters in diameter, is 1,600 millime-

ters long and weighs 1,000 kg), special

strategies are necessary for machining.

Due to its weight and also the forces

on the machining, the workpiece bends

and becomes misshapen. Where high

levels of accuracy are demanded, there

must be precise compensation for

these sources of error.

For this purpose MÄGERLE has devel-

oped a compensation algorithm which

measures the deflection of the work- Speaks for itself: Edges of the printing roller are ground absolutely precisely on the MFP-220

L_Station1_E.indd 8 15.04.2009 14:04:43 Uhr

The combination professional:

The MÄGERLE MGC-L-330

with fully automatic tool changer

Dittel Messtechnik GmbHTel.: +49 (0)8191 3351-0www.dittel.com

We optimize your grinding process

Schleifring Grinding Symposium 2009

Meet us

6.– 8. MaiThun/Schweiz

hydrostatic guidance concept makes it possible to move heavy work-

pieces almost without friction, which makes a decisive contribution to the

quality of the surface finish. The combination of machine concept with

hydrostatic guidance, integral measurement and fully automatic compen-

sation guarantees the customer an optimum result, even for the heaviest

components.

Complex combined machining

However, modern MÄGERLE grinding centers don’t only solve pure grin-

ding tasks in a reliable manner. They also handle complex combination

machining with geometrically-defined cutting edge such as hard turning,

hard milling or drill-ing too. Machining the workpieces in a single clamp-

ing also has decisive influence on productivity and on quality of the com-

ponent. An ex-ample of such a combination machine is the MÄGERLE

MGC-L-330. The grinding center comprises a fully-automatic tool-chang-

ing sys-tem, a horizontal grinding spindle and a table dressing device.

Machining with geometrically defined cutting edges is carried out with

an additional vertical direct drive spindle, which can be swiveled through

90°. Due to the extreme rigidity of the large-area hydrostatic guides, im-

pressive cutting values can be

achieved. The result speaks for itself:

reduced machining time and the

greatest possible accuracy.

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FURTHER INFORMATION

STAND


10 MOTION 01/09


For ward- look ing sur face and prof i le gr inding

The next generationFast and outstandingly user-friendly – these are the convincing advantages of the moderncon-trol and machining systems by BLOHM JUNG.

outstanding performance and process reliability are thoroughly convincing. As

a basic machine equipped with three axes, it can be upgraded to a fi ve-axis ma-

chine with a high-speed rotary table and a swiveling grinding spindle drive. It

can grind different profi les in a single clamping – with concave or convex radii,

as desired, and it can also be used for drilling, milling or grinding. Speed-stroke

grinding is known for its fast traverse speeds and acceleration and a fast machin-

ing process and very short cycle times. On account of the fast feed rate – 80 to

120 m/min at infeed rates of up to 0.01 millimeters per traverse stroke – a large

proportion of the process heat is carried away by the chips. The edges of the

workpiece remain undamaged even where the cooling and grinding conditions

are less than optimum. A well thought-out procedure for the process rounds off

the profi le of the PROKOS. The selection of parameters is simpler, the coolant

feed is less critical and the performance limit can easily be determined from the

wear on the grinding wheels.

With the CNC-Light Control, BLOHM

JUNG introduces a new genera-

tion of controls. It can interpolate up to

four axes at the same time and traverse

them towards each other. The technology

is thus perfectly suited for high-end ma-

chines with a limited number of axes. The

special feature of the CNC-Light Control:

both the FANUC control operator panel

and the functional scope of the machining

possibilities (cycles) were a complete in-

house development by BLOHM JUNG.

A new feature is the method of working

with the workstation editor, which is ori-

ented towards the STUDER pictogram-

ming (see Station 5). Broadly in line with

the motto ‘more pictures – less words’,

BLOHM JUNG introduces the user-

friendly working method of the new con-

trol on a PROFIMAT at Station 2.

Breathtaking speed

Also at Station 2: the latest news in

speed-stroke technology, as exempli-

fi ed by the PROKOS, which grinds fi ve

sides of a workpiece in seven grinding

operations (see table). Its features of

Right at the top: The speed-stroke technology of

the PROKOS means very short cycle times

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FURTHER INFORMATION

STAND

5-SIDED-GRINDING ON THE PROKOS

Operation stages 1 + 2

Wheel No. 1 – traverse plunge – grinding wheel

set angle (A-axis) = 70°

Operation stages 3 + 4

Wheel No. 1 – traverse plunge –

set angle 25°

Operation stage 5

Wheel No. 2 – traverse plunge –

set angle 45°

Operation stage 6

Wheel 2 – profi le traverse grinding with

three interpolating axes – set angle 45°

Operation stage 7

Wheel 3 – fl at grinding with continuous

traverse – set angle 20°

Workpiece: Length × breadth × height = 100 × 70 × 40 mm – 3 grinding wheels

L_Station2-3_E.indd 10 09.04.2009 14:49:11 Uhr

11MOTION 01/09

Ready for use in six minutes

For profi le grinding, different dressing systems are

available for the VARIO range of profi le grinders by

BLOHM JUNG. According to requirements, profi led

crushing units, fi xed profi le diamonds or swiveling

diamond wheels are mounted on the grinding table.

Highlight is the CNC PA37K head dressing unit. The

possibility of using both individual diamonds and

driven diamond wheels for profi ling is unique in the

world. Even when preparing the diamond tools the

automatic diamond adjustment saves a lot of time. A diamond star with six dia-

monds is ready for use in only six minutes, a diamond wheel in ten. The function

‘CD Abrichten’ (continuous dressing), or parallel dressing, cuts machining times

by up to 50 per cent.

Determine, analyze, compensate

But even the best dressing tools wear, and this has an infl uence on dressing con-

tours. BLOHM JUNG shows at Station 3 how the GEOID correction software

determines the actual contour of the diamond via a measuring probe and then cor-

rects the dressing program accordingly. Thus GEOID compensates for the wear in

individual diamonds and diamond

wheels, in-creases the usability of the

dressing tools by a multiple and re-

duces the costs of tools considerably.

Grinding wheel profi les cannot be

exactly dressed without the use of

a geometrically-perfect dressing tool.

Even new diamonds are not always per-

fect. At the SCHLEIFRING Grinding Sym-

posium 2009, BLOHM JUNG pre-sents

for the fi rst time ever under the expres-

sion GEOID a new development for

compensa-tion of contour faults in dress-

ing tools. The example shows the quick

manufacture of a blanking punch on the

VARIO D. GEOID was developed in con-

cert with the Georg Simon Ohm Univer-

sity in Nuremberg. The software for

com-pensation of uneven wear in dress-

ing tools is a further development of the

automatic diamond adjustment by

BLOHM JUNG and is used in conjunction

with the CNC PA37K profi le dressing de-

vice and the table version PA130TM.

Topography of the cutting edge of the

dressing tool can be determined with

μ-accuracy using GEOID. The correction

values calculated are fed directly into

the dressing program and create a per-

fect contour on the grinding wheel. Re-

sult: an increased service life for the

dressing tool, reduced costs of tools and

the contour accuracy is improved.

GEOID diamond-wear compensat ion

It all depends on the contourGEOID wear compensation eliminates faults on dressing tools accurate to the last μ.

Swiveling: GEOID in combination with

flexible dressing systems guarantee perfect

contours on the grinding wheel [1 + 2]

Best contour

accuracy:

Produce perfect

workpieces with

GEOID

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FURTHER INFORMATION

STAND

[1][1]

[2][2]


12 MOTION 01/09


STUDERmodular

Your personalized S22The customer’s workpiece is the focal point. The customer chooses what he really needs,just like a construction kit. No more and no less. The choice leaves nothing to be desired.

High-speed grinding (HSG) with cutting speeds of 80 to 140 m/s or heavy-

duty applications for grinding wheels of 610 mm diameter and 160 mm width.

The S22 is compatible with various loading and unloading systems and can

be loaded from both sides and from above. The platform is suitable for linking

several machines together

Two different axis drive systems are available. The X-axis has antifriction

guideways as standard and the Z-axis has guideways with a patented surface

structure. Both axes have ball screw linear drives

Direct drive and non-contact guideways are optional for both axes. The

combination of hydrostatic guides and linear motors permits axis movements

of up to 30 m/min. Precision to a tenth of a micrometer is easily achieved,

thanks to the measuring system resolution of 0.01 μm

The platform concept can be experi-

enced close up at the Grinding Sym-

posium.

The new production platform can be

confi gured for almost every grin-

ding task. Effi cient production grinding,

high-speed grinding or heavy-duty

applications – the S22 has a construc-

tion set at its disposal fi lled with every

component STUDER has ever devel-

oped and produced for CNC production

machines. From workpiece spindle

heads with chuck or universal design,

to standard or high-precision C-axes

with different power settings of belt or

motor spindle head, to tailstocks for

standard, synchronous or fi ne grinding

applications. Various dressing options

and accessories such as measuring

control and clamping devices complete

the range of services. In short, indi-

vidually equipped to customer require-

ments, the S22 is the perfect machine

– for heavy-duty applications as well

as fl exible production.

Sophisticated software

Sophisticated software completes

the mechanical concept of the S22.

StuderWIN operator interface and

StuderGRIND software modules guar-

antee the effi ciency of the machine.

Integral measuring system, handling

system, sen-sor technology for process

monitoring and automatic balancing

systems ensure standardized program-

ming of the different systems. These

and the following performance fea-

tures make the STUDER S22 a real all-

rounder:

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FURTHER INFORMATION

Modular design: Production grinding and dressing (top right), heavy-duty plunge grinding (be-low right),

high-speed grinding with two grinding wheels (below) or non-circular grinding (below left) – the S22 can be

confi gured fl exibly and individually to customer requirements

STAND

L_Station4-5-6_E.indd 12 15.04.2009 12:48:33 Uhr

13MOTION 01/09

an automatic swivel function. A tiltable dressing

unit ensures perfect dressing conditions for internal

grinding without compromising geometries.

Using three grinding wheels brings distinct advan-

tages. Machining the workpiece in one set-up guar-

antees optimum concentricity and at the same time

eliminates downtime for re-clamping. Special

STUDER grinding software helps to utilize the ma-

chine’s full potential. ‘Pictogramming’ software

supports the operator when creating effi cient grin-

ding and dressing programs. STUDER Quick-Set®

set-up software facilitates workpiece set-up and

changeover. StuderThread software helps when

programming the dressing program for thread

grinding. Following the completion of this machin-

ing process, the workpiece is ready for the next

process steps.

Bearing inner ring on the S12

The high-tech S21 excels at machining a bearing

inner ring. A combination of linear drives and hy-

drostatic guideways gives excellent results

when traveling in interpolation mode. The po-

sition measuring system used also offers ma-

jor advantages. A resolution of 0.01 μm can

achieve accuracies in the region of a tenth of a micrometer.

All the benefi ts of the S12 are demonstrated to their best advantage by

the example on show. Nowadays, radius dressing devices often guarantee

the dimensional accuracy of the radius. They prevent fl exible manipulation

of the radius, however. The S12 is defi nitely more fl exible in this instance,

thanks to the high traverse accuracy

of the guideway and the ability to

program the radius with the CNC

control system.

Manufacturers of small and micro

parts have known the secret for

some time: STUDER cylindrical grinding

machines impress with precision, pro-

ductivity and reliability. If all-purpose

and highly effi cient machining of small

parts is required, then the S21 universal

cylindrical grinder or the S12 cylindrical

production grinder is for you.

Pressure piece with external

thread on the S21

The largest external diameter of the

30-millimeter-long component is 18

millimeters; the internal diameter is 7

millimeters. The S21 grinds workpieces

in one set-up and can be equipped with

two external grinding wheels and one

high-frequency spindle for internal

grinding. The B-axis is equipped with

STUDERmicro

You can’t get more accurate than thisSTUDER shows the machining of small precision parts for individual and production operations with accuracies of up to a tenth of a micrometer.

Example: Machining of a

pressure piece with external

thread on the S21

High-tech machine: The S12 with linear motors and

hydrostatic guideways

Angular infeed grinding

Thread grinding

Internal grinding

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FURTHER INFORMATION

STAND


14 MOTION 01/09


STUDER internal

From the inside outSTUDER further expands its portfolio with machines produced by COMBITEC, its new subsidiary. The aim is to increase technical knowhow and application possibilities for internal cylindrical grinding.

grinding collet chucks and machining brittle hard materials. Special features are

the linear spindle arrangement, use of either one or two belt spindles with speeds

of between 28,000 and 60,000 min-1 and cross-slide design. The CT-450 provides

a range of expansion options, such as a C-axis for grinding all types of threads.

CT-960 – a high-end universal machine

The internal, universal and radius grinder CT-960 is a high-precision machine,

with a B-axis swivel to 91 degrees. A turret for up to four spindles permits effi -

cient grinding of small to medium-sized workpieces. In this particular design,

the machine is suited for universal grinding tasks as well as specifi cally for grin-

ding complex workpieces of brittle hard materials like carbide, ceramics or sap-

phire. The optimum stability and rigidity of the CT-960 also permit grinding die

with radii, cones or path contours. The fi nished workpieces have polished surface

quality. An optional CNC-controlled C-axis is available for grinding threads or

Strong partners for every possible

task: With the takeover of Com-

bitec AG of Switzerland, STUDER has

substantially increased its grinding

expertise in the internal cylindrical

grinding sector. Whether die grinding,

series production of precision parts for

the aerospace and hydraulics industry

or diesel injection technology, at Sta-

tion 6, STUDER presents three techni-

cally mature production solutions: the

CT-450L, the CT-960 and the S120.

CT-450L – entry-level

model for new users

The CT-450L CNC internal and universal

cylindrical grinder for new users is the

light version of the COMBITEC bestsell-

er CT-450. With a wide range of applica-

tions, the CT-450L is equally suited to

universal internal grinding applications,

The light version of the CT-450:

The entry-level CT-450L

Innovative injection technology: Just one of many uses in the application area of internal cylindrical grinding

STAND


15MOTION 01/09

dent grinding tasks. Optimally suited for an effi cient machining of high-precision

small parts, it is well established in large batch production. Typical applications

are in the area of hydraulic components and increasingly in medical technology,

for example grinding ceramic balls for hip joints. Different handling systems can

be integrated via the well-defi ned loading interface without too much effort. The

automated solution on show perfect-

ly combines productivity with fl exibil-

ity and in addition, it impresses with

short retooling times.

non-circular shapes. Sim-CT software

helps with programming, set-up and

simulation.

S120 – a speedy

production machine

The S120 production internal cylindrical

grinding machine is the ideal compact

internal grinder for one or two indepen-

+ + + m i c h e l e . f a h r n i @ s t u d e r . c o m

+ + + w w w . s t u d e r . c o m + + +

FURTHER INFORMATION

Excellent: The

STUDER S120

combines

productivity and

fl exibility

Internal cylindrical grinding: Efficient machining of

high-precision small parts


16 MOTION 01/09


SERVICE Qual i t y

Fountain of youth for machinesAnyone who is familiar with possible wear phenomena starts to think about the health of his machine. A professional overhaul extends its service life.

Preventive SCHLEIFRING Service

SCHLEIFRING machines are similar to our bodies in this respect: systematic

servicing carried out by SCHLEIFRING SERVICE (which can be compared to rou-

tine checks by the doctor) extend machine running times and availability and in

addition improve the grinding result. Preventive servicing documents the current

state of the machine. We recommend an annual service with SystemTM. Using

this, SCHLEIFRING SERVICE checks more than 100 points on a checklist and

measures the geometric values and the hysteresis. All the wear parts in the ma-

terial list are replaced as a preventive measure. In addition to this, SERVICE

diagnostics and life cycle monitoring provide valuable insights into the condition

of the grinding machine and recommend that corresponding precautions are

taken. More than 3,000 satisfi ed customers are already enjoying the benefi ts

of SERVICE Check. The specialist knowledge of the SCHLEIFRING experts

means that you can avoid cost-intensive machine down times, particularly in

these economically diffi cult times.

Good and benefi cial

After a complete overhaul by SCHLEIFRING SERVICE the ma-

chines once again operate just as precisely and reliably as

new machines. The modular overhaul system thus works

rather like a fountain of youth. And the process is even more

benefi cial. The cost of a complete overhaul is between 40 and

70 per cent of the price of a new machine.

And by the way: more than 100 overhauls are carried out an-

nually, using nothing but SCHLEIFRING original components.

They are only done in

the relevant produc-

tion factory of the

SCHLEIFRING Group.

High blood pressure is the number

one cause of illness in most indus-

trialized countries. If not detected and

left untreated, it can lead to serious con-

sequences such as heart attacks and

strokes. Yet high blood pressure cannot

be felt; only health checks can supply

the information as to whether it is high-

er than it should be even though every-

thing appears normal. If caught at the

right time, medicines or a preventive

change in lifestyle can help. We often

do not realize how important our health

is until it is too late.

16 MOTMO ION 01/09

terial list are repla

diagnostics and life

of the grinding m

taken. More tha

of SERVICE Che

means that you c

these economica

New from old: An assembly before

and after overhaul

Maintenance cycle: Professional machine diagnostics in three steps

+++ s a n d r o . b o t a z z o @ s e r v i c e a g . n e t

+++ w w w. s e r v i c e a g . n e t +++

FURTHER INFORMATION

Servicing with System TM

More than 100 testing and measuring points

Diagnostics and recommendations

Information on the current state of the grinding machine

Life Cycle Monitoring

The test measurements are evaluated by specialists

STAND


17MOTION 01/09

Two workpieces are

machined simultane-

ously in two different

operations with CBN

wheels using the an-

gular plunging pro-

cess. The cycle time,

including a dressing

component, is less

than 13 seconds. The

workpieces are trans-

ported and sent on

using a paced triple

gripper system.

One of the machine’s special highlights is the dressing system for the CBN

wheels. This uses software that MIKROSA has developed in-house. It uses in-

tegrated sound sensors in two directions to set the dressing start points. This

guarantees a preset dressing depth, not exceeding three μm, on the surface and

the shoulder of the CBN wheel.

A standardized handling system uses the ‘keyhole principle’ to transport the

workpieces into the machine and out again. External handling systems such as

palletizing machines can easily be connected via an interface. Centerless precision

– if all its process technology features are fully utilized, the potential of the KRONOS

S 125 is enormous. The highest quality and productivity, the ability to process a

wide variety of different materials and

the use of versatile grinding techniques

– MIKROSA grinding machines meet

every requirement of the market.

The KRONOS S 125 centerless ex-

ternal cylindrical grinding machine

is designed with a special construction

principle for the use of the CBN grin-

ding technique. It is based on a ther-

mally stable and vibration-damped

moulded mineral machine bed. The

cross-slide systems that are built onto

this bed for the grinding and regulating

wheel side make the centerless grin-

ding machine enormously versatile.

The large number of variations, rang-

ing from throughfeed grinding and

plunge grinding to reciprocating grin-

ding including angular plunging, cycle

changing and offset grinding.

Two operations at once

At the 2009 Grinding Symposium,

MIKROSA is demonstrating the ma-

chine’s versatility, using the machining

of injector needles (Ø 4.0 × 48 mm) in

a high-speed process.

MIKROSA KRONOS S 125

Fit for every challengeIn the high speed grinding of injector needles the MIKROSA KRONOS S 125 demonstrates an unusually fl exible ability to adapt to the grinding task.

The angular plunging process: Simultaneous grinding of injection nozzles

with CBN wheels using different operations on the KRONOS S 125

Vast potential: The KRONOS S 125 was designed from

the start with CBN grinding in mind.

+ + + i r i n a . h a f n e r @ m i k r o s a . c o m

+ + + w w w . m i k r o s a . c o m + + +

FURTHER INFORMATION

DESIGN HIGHLIGHTS

Operation 1

CBN grinding by angular plunging

Pregrinding the shoulder

Pregrinding the tip

Securing with a pressure roller

Operation 2

CBN grinding by angular plunging

Contour grinding

Finishing the face

STAND


Meister Abrasives AG · Switzerland · www.meister-abrasives.com

Make A Quality Decision InternationalMeister Abrasives


19MOTION 01/09

with wear-free drives enables the tool spindle to be positioned with extreme pre-

cision and at the same time maximizes service life. This ensures the most accurate

grinding results, even in the case of camshafts. The CamGrind S version of this

machine is already used successfully for camshaft grinding.

The SCHAUDT ShaftGrind S is de-

signed to machine a variety of shafts

effi ciently. It has WOP-S programming,

which is based on the Siemens 840D

control panel and helps to generate sur-

face contours such as polygons, ellipses

and free profi les with ease. The machine

is also eminently suitable for high-speed

peel grinding (HSP) processes and slot

grinding with CBN.

Machining transmission shafts

Seats for transmission shafts are usu-

ally ground in an indexing process, ei-

ther by straight plunging or high-speed

peel grinding. The ShaftGrind S with its

S2 tilting spindle enables different

widths of grinding wheel to be used and

permits the interpolation of undercutting

and plunge cutting with an electroplated

grinding wheel. This markedly increases

the productivity of the machine. When

high speed plunge grinding with CBN,

the ShaftGrind S reaches cutting speeds

of 200 m/s. This, together with the car-

bon-carrier system of the machine,

makes the process even more produc-

tive. The ShaftGrind S is designed for

lubrication with emulsion or oil in com-

bination with CBN grinding wheels.

Grinding wheels that are 480 millimeters

in diameter guarantee long tool life. An

optional hydrostatic guide for the X axis

SCHAUDT Shaf tGr ind S

The perfect shaftTransmission shafts up to 650 millimeters long are the province of the SCHAUDT ShaftGrind S with tilting spindle technology

Effi cient machining

taken care of:

Machine confi gura-

tion of the ShaftGrind

S with tilting spindle

that can be swung in

+ + + i r i n a . h a f n e r @ s c h a u d t . c o m

+ + + w w w . s c h a u d t . c o m + + +

FURTHER INFORMATION

Outstanding results: The ShaftGrind S

has cutting speeds of 200 m/s

STAND

ADVANTAGES AND PERFORMANCE

Machining of round and non-round materials up to 650 mm long,

weighing up to 50 kg

Programming with WOP-S is quick and easy

Hydrostatic guide for the X axis (optional extra)

Moulded mineral machine bed (Granitan® S 103) with optimized damping

properties and extremely high thermal stability

Technical specifi cations

Sinumerik 840D controller

Integral SPEED-LOAD loader (option)

Grinding length/tip height: 650 mm / 175 mm

Spindle confi guration

Grinding wheel diameters large/small wheel: 480 mm / 140 mm

Grinding wheel widths large/small wheel: 80 mm / 70 mm

Output using large/small wheel: 40 kW/8 kW

2 grinding spindle locations (one spindle can be tilted)


20 MOTION 01/09


SCHAUDT CamGrind L2

Synchronicity wins on pointsThe SCHAUDT CamGrind L2 with swivel-in spindle technology and specially-designed speed profi le machines two cam contours synchronously – main and auxiliary machining times are drastically reduced.

The SCHLEIFRING company

SCHAUDT shows the latest devel-

opment of the CamGrind L at Station

10. The current machine concept is de-

signed to meet the requirements for

mass production of series components

– with the greatest possible fl exibility

and ease of refi tting. The two-cross-

slide version with its special speed

profi le makes it possible to machine

two offset cam contours at the same

time in one clamping. The new hydro-

statically suspended workhead even

permits, with optimum machine spec-

ifi cation with four grinding spindles,

Fast and simple: Complete fi nishing in just one clamping

ADVANTAGES AND PERFORMANCE

Simultaneous machining with two grinding wheels reduces working times

Reduction in the auxiliary times by one tool-change procedure

Low marginal costs for an additional investment with increasing production

quantities

Portal loading system or integrated loader SPEED-LOAD (option)

Technical specifi cations

Sinumerik 840D control

Grinding length/maximum height: 800 mm/220 mm

Spindle confi guration

Grinding wheel diameter large/small wheel: 480 mm/250 mm

Grinding wheel thickness large/small wheel: 80 mm/55 mm

Output large/small wheel: 40 kW/30 kW

Three grinding spindle positions (one swivel-in grinding spindle)

synchronous grinding of in-

clined cam radii. A forward-

looking machine concept.

A successful design

principle

Know-how of camshaft grin-

ding has for years been based

very successfully on the WOP-

S programming system. High-

resolution glass scales guar-

antee the accuracy of the

X-slides. Hydrostatic guides

for the slides and the use of

the swivel-in spindle technol-

ogy round off the well-thought-

out concept to perfection.

In this way, the new CamGrind

L2 is suitable for cylindrical

STAND


21MOTION 01/09

When clamping becomes critical …Extraordinary applications demand extraordinary solutions. Many workpieces cannot be properly clamped by virtue of their unique characteristics. We develop targeted customized chucking systems.

FORKARDT SCHWEIZ GMBHIndustriestrasse 3, CH-8307 EffretikonTel. +41 52 355 31 31, [email protected] ITW Workholding Comp

WWW.FORKARDT.CH Highest quality and precision within the μm range

and non-circular grinding as well as for

keyway plunge grinding and HSP-grin-

ding with CBN. On this type of machine,

only CBN tools with ceramic, galvanic

or metallic bonding are used.

Finished: A camshaft after the grinding process

+ + + i r i n a . h a f n e r @ s c h a u d t . c o m

+ + + w w w . s c h a u d t . c o m + + +

FURTHER INFORMATION

[2][2][1][1]

Deep insight: [1] Example

of a machine confi gura-

tion with a swivel-in

grinding spindle [2] View

of the inside of the

CamGrind L2 with the

two-slide version


22 MOTION 01/09


STUDER f lexible

Seven at one strokeWith the upgrade to three cross-slides, the unique combined machining system STUDER S242 has become the most fl exible hard fi ne machining center available.

confi guration possibilities for external and internal grinding

(with up to three internal grinding spindles). External or internal

hard turning, hard reaming, milling (with up to twelve driven

tool positions) and drilling all benefi t from the wide range of

confi gurations. Equipped with two cross-slides, the S242 has a

center distance of 400 and 1000 millimeters. With the three cross-

slide version, an additional variant with a center distance of 800

millimeters is available. Unrestricted chip removal when hard

turning is ensured by the inclined GRANITAN® machine bed. A

chip conveyor takes care of swarf discharge.

Quick retooling

The S242 is mainly used in the sectors of machine tools and tool

making, pneumatics/hydraulics and the electrical/electronic

sector. High fl exibility of the machine and fast retooling with a

synchronous opposed spindle on the tailstock (W-axis) makes the S242 an in-

teresting proposition, also for contract manufacturers who machine mainly in-

dividual components (part families) and small lot sizes. Newly developed control

measuring cycles with a measuring probe mounted in the revolving turret allows

the automatic calculation of insert wear. This process allows measuring data to

be recorded and printed. The well-proven in-house design STUDER easyLoad

XL is offered for workpiece automation. Combining the machining processes of

cylindrical grinding and hard turning with parallel grinding spindles and a turret

guarantees productive, accurate and reliable complete machining of workpieces.

STUDER demonstrates these processes

visually during the Grinding Symposium

with machining shafts and chuck compo-

nents at Station 11.

Arange of capabilities that is second

to none: ongoing continued devel-

opment has meant that nowadays the

STUDER S242 is capable of at least

seven machining processes: external

hard turning and grinding, milling of

small grooves, internal hard turning and

grinding, external thread turning, drill-

ing and hard reaming. This means that

the S242 is capable of machining spin-

dles and guide pillars, pump pinions,

armature shafts, tool holders and other

specifi c components, among others.

Complete machining of a variety of

workpieces in a single clamping makes

increases in productivity of up to 70 per

cent a real possibility.

Wide range of confi gurations

The S242 has parallel grinding spindles,

a turret as well as two or three cross-

slides. This results in ten or rather 15

Flexible and multi-functional: S242 with three cross-slides (external

grinding, turret, internal grinding turret)


+++ w w w . s t u d e r . c o m + ++

FURTHER INFORMATION

FLEXIBLE, PRODUCTIVE, ACCURATE, RELIABLE

Less production time and down time due to quick retooling of the machine

High positional and rotational accuracy

Complete machining in a single clamping

Appropriate surface structures

In-process measuring of diameter and length

STAND


23MOTION 01/09

STUDER inte l l igent

Intelligent software pays offStuderTechnology optimizes the grinding process – and increases the effi ciency of universal cylindrical grinding machines by 50 per cent or more.

automatically calculates the process parameters. At the push of a button, the

operator learns which in-feed speeds, changeover points, dressing amounts and

spark-out time the system recommends.

Profi ting from the knowledge of many

Behind all these intelligent functions is a technology database with invaluable

expert knowledge. It makes sure that the machine control is always able to choose

the best available data. Unlike most operators who often habitually work with

the same standard values and who rarely manage to keep to the tolerances on

their fi rst attempt. Such a process is ineffi cient and requires time-consuming

optimization procedures. However, if StuderTechnology is used, near-optimum

values are reached straight away, resulting in reduced set-up times and grinding

times lowered by up to 25 per cent. In addition, the optimization time is often

zero and costly errors hardly ever happen. StuderTechnology with its many and

various functions like virtual machine set-up

and program simulation result in an early

detection of errors and is additionally ex-

tremely user-friendly.


+++ w w w . s t u d e r . c o m +++

FURTHER INFORMATION

Intelligent software makes it possible:

machine operators can once again

concentrate on their key task – the quick,

safe and simple generation of a grinding

program. At Station 12, STUDER dem-

onstrates with the S31 and S33 univer-

sal cylindrical grinding machines how

StuderGRIND software and the Studer-

Technology module can contribute to

reducing cycle times by 50 per cent.

Everything at the

push of a button

Some of the tasks of a machine opera-

tor are to choose the appropriate tool-

ing, set up and retool the machine

quickly, develop the grinding process

and grind accurate parts. He should

be able to leave everything else to

the StuderGRIND CAM software and

StuderTechnology. He only has to enter

the type of material, specifi cation of the

grinding wheel, type of dressing tool

and certain other factors. The software

Graphic visualization: User-friendly work with

StuderTechnology

STAND

Achieving the best with StuderTechnology

StuderTechnology versus empirical values (after optimization): The software is most benefi cial for small and medium

quantities. Example: a shaft is to be machined on three diameters. The surface accuracy should be Ra 0.3, the

roundness no more than 1 μm. A total of six values are measured. When grinding with empirical values the tolerances

were not achieved and time-consuming optimization was necessary

StuderTech

StuderTech

StuderTech

Tim

e [h

:min

:s]

8 : 24 : 00

7 : 12 : 00

6 : 00 : 00

4 : 48 : 00

3 : 36 : 00

2 : 24 : 00

1 : 12 : 00

0 : 00 : 00

Empirical values

Empirical values

Empirical values

DocumentationOptimization timeDressing timeGrinding timeProgramming

– 90 % – 75 %

1 unit 10 unit 100 unit

– 25 %


24 MOTION 01/09


EWAG COMPACT L INE

Compact? Great! The EWAG COMPACT LINE scores with its compact design, ergonomic operation and its integrated robot system for fl exible manufacture of inserts.

clamping systems are mechanically identically installed on the B-axis and are

identified by a ‘plug and play’ system. The result is maximum flexibility and

shortest changeover times.

Dressing, regenerating, crushing

The ‘three-in-one’ sharpening unit: dressing – regenerating – crushing provides

perfect grinding wheel concentricity and high repeat accuracy of processes. 3D

measuring of workpieces in one clamping ensures the required tolerances are

met starting with the fi rst part. Loading is carried out with the integrated 6-axis

FANUC robot which increases the level of machine automation and permits

autonomous multi-shift operation. The

COMPACT LINE which incorpo-

rates 5-axis CNC kinematics,

direct drive of the grinding

spindle and linear technology

allows users to effortlessly

keep pace with changing mar-

ket requirements.

The EWAG COMPACT LINE is de-

signed for the fl exible and highly

precise manufacturing or resharpening

of indexable inserts in all materials.

Whether the material is carbide, cer-

met, ceramic or super-hard CBN/PCD

– the CNC grinding machine meets all

of the requirements for precision and

speed – especially with the realization

of complex workpiece geometries. The

machine is fi tted with the new CBN/

PCD module for grinding super-hard

materials and now also for machining

diamond cutting materials, as EWAG

demonstrates at Station 13.

The COMPACT LINE sets new standards

in small spaces with compact construc-

tion, ergonomic operation and an inte-

grated robot system. Inside the ma-

chine, everything is positioned close to

the working B-axis; the travel ranges

for axes and robots are thus kept to a

minimum, cycle and down times are

shortened considerably and productiv-

ity is increased. The entire machine

interior as well as all control elements

are accessible from one position.

Fast, accurate, autonomous

A rapid change system allows the op-

erator to exchange the grinding wheels

effortlessly at the push of a button.

The HSKE 50 clamping system for

grinding wheels ensures quick and ac-

curate changeover of grinding wheel

sets. The workpieces are fixed to the

clamping device with a tension pin. All

+++ t h o m a s . f i s c h e r @ e w a g . c o m

+++ w w w . e w a g . c o m +++

FURTHER INFORMATION

EWAG COMPACT LINE:

Grinding in the smallest space

Ergonomic: Control elements and machine

interior are accessible from one position

New measures: All grinding programs can be

programmed on the touch screen panel

STAND


25MOTION 01/09

PCD. EWAG guarantees highest concentricity requirements and geometric tol-

erances by using a special chuck which allows automatic tool changing. Fully

automatic loading of the machine is carried out by a 6-axis robot. Each EWAMATIC

LINE meets specifi c customer requirements. Superior fl exibility makes a mul-

titude of grinding operations possible in one clamping, guaranteed by the star-

shaped grinding head with its repeat accuracy of 2 μm. It can hold up to twelve

grinding wheels. Once the grinding wheel has been dressed on the machine,

concentricity and run-out are guaranteed at the highest level. Features such as

pressure-controlled grinding, automatic grinding wheel regeneration and inte-

grated measuring cycles with adequate compensation make fully automatic

grinding of CBN and PCD tools possible. The machine can be equipped with an

eroding process for the production of PCD tools. Users achieve close shape and

positional tolerances with effi cient eroding and grinding in one clamping. Three

criteria are the core of the machine autonomy:

Automatic feed control

Integrated dressing of the grinding wheels

Dimensional measuring directly on the machine

Functionality

The EWAMATIC LINE has another big advantage: the user can employ grinding

wheels of up to 300 millimeters diameter and also the smallest mounted points.

The machine has a high-speed spindle to reach the cutting speeds necessary

for mounted points. It permits speeds of more than 20,000 rpm.

In this set-up, the machine

optimally grinds so-called

pockets for example, which

are subsequently equipped

with CBN or even PCD blanks.

A new operator panel with

hot keys already complies

with the standard of tomor-

row. Users are able to carry

out grinding simulation di-

rectly on the EWAMATIC LINE

with a Windows XP operating

system installed on a high-

performance IPC system.

At the Grinding Symposium, EWAG

demonstrates fully automated

machining of PCD/PCBN equipped

highly complex round tools on the

EWAMATIC LINE. The 6-axis CNC grin-

ding center has many applications:

machining and regrinding of highly-

complex workpieces, rotationally sym-

metrical tools, indexable inserts from

HSS/carbide as well as the latest cut-

ting materials, like super-hard CBN/

EWAG EWAMATIC L INE

The effi cient oneEWAG presents the EWAMATIC LINE at the Grinding Symposium, a tailor-made tool grinding machine for machining highly complex PCD tools

+ + + t h o m a s . f i s c h e r @ e w a g . c o m

+ + + w w w . e w a g . c o m + + +

FURTHER INFORMATION

Technology of the future: The operating system

carries out simulation directly on the machine

Practical turbo: The high-speed spindle can reach speeds of up

to 20,000 rpm without effort

STAND


26 MOTION 01/09


Micro tools

High-performance double actThe HELITRONIC MICRO and the HELICHECK PLUS are the perfect machine combination from WALTER for the manufacture and measurement of micro tools of the highest surface quality.

trolled via integral high-resolution measuring systems which

produce precise movements with simultaneously high dy-

namics. The grinding spindle head is equipped with three

grinding spindles guaranteeing a high degree of fl exibility.

A secondary X-axis allows for the precise and automatic

positioning of tools to the center of rotation of the C-axis.

Additional guiding and support of the workpieces by hy-

draulically activated steady rests supports with fi ne adjust-

ment ensure high dimensional and rotational accuracies.

The machine concept is complemented by an integrated

loading system served by a 6-axis industrial robot for work-

piece loading.

HELICHECK PLUS

Optical, non-contact measuring technologies play a decisive

role, especially with delicate materials and micro dimen-

sions. WALTER sets new standards with the HELICHECK

PLUS. The fourth camera with 400× magnifi cation provides

the deciding PLUS element and increases the application

range for tools as small as 0.1 millimeter diameter. Front

and top light cameras also magnify the object to be mea-

sured by 400 times. Even the smallest details become vis-

ible and measurable. Primarily, it comes down to perfect

lighting of the micro tools which are barely visible with

the naked eye. WALTER sharpens your vision by effi -

cient image processing and easy-to-use measuring

control. A special edge detection system, optimized

lighting and image enhancement techniques ensure

that even high-gloss polished, coated or matt surfaces

can be measured with high repeatability.

The development of micro tools has

seen a rapid upswing in recent

years. They are used for machining the

smallest components in the electronics

industry and the medical and dental

sector and they require the utmost pre-

cision. Without accurate measuring

technology the manufacture of preci-

sion micro tools is no longer possible.

At Station 15, WALTER shows how the

surface quality of micro tools has a

considerable infl uence on the service

life of the machine as well as on the

quality of the workpiece.

HELITRONIC MICRO

The HELITRONIC MICRO provides all

the prerequisites for highly accurate

grinding results for tools within the 0.5

to 10 millimeter diameter range. The

machine has six CNC grinding axes

with linear motors and torque motors

on all rotational axes. All axes are con-

[1][1]

[2][2]

[3][3]

[4][4]

[5][5]

Well measured:

First-class surface

quality with the

HELITRONIC MICRO [1].

The HELICHECK PLUS

magnifies object 50 to

400 times [2 + 3]

Result of the image

enhancement technique

with a micro tool

Ø 0.8 mm [4 + 5]

Ideal conditions: The HELITRONIC MICRO achieves

high-precision grinding results

+++ c h r i s t o p h . e h r l e r @ w a l t e r - m a c h i n e s . d e

+++ w w w.w a l t e r - m a c h i n e s . d e +++

FURTHER INFORMATION

STAND

0.2 mm diameter magnifi ed 400 times

0.2 mm diameter magnifi ed 50 times


27MOTION 01/09

Changer with 8 positions

The trend is towards an increasing range of geometries

and longer unmanned machining cycles. WALTER takes

on this development with the electrode/grinding

wheel changer with 8 positions for the HELITRONIC

POWER DIAMOND which holds up to 24 electrodes

or grinding wheels respectively. This ensures ex-

cellent machining properties of PCD and carbide

tools with extremely complex tool geometries.

When eroding stepped contour tools with different

concave contour radii for example, the best-suited rotat-

ing electrode is simply selected.

The coolant supply manifold is connected to the electrode/grin-

ding wheel adaptors. This guarantees optimum cooling at all times during the

production process when tool grinding and optimum protection when eroding.

In addition, the tool changer extends unmanned machining time for night-shift

and week-end operation. The two-in-one concept of the HELITRONIC POWER

DIAMOND enables fl exible reaction to current production requirements. Auto-

matic changeover from eroding to grinding, from machining PCD tools to process-

ing or resharpening carbide tools

is possible. Furthermore, complete

machining of almost all types of

tools is also feasible.

WALTER’s answer to the

ever-increasing stan-

dard of surface accuracy and

cutting edge quality is the

HELITRONIC POWER

DIAMOND. The machine

impresses with a 4-stage

erosion process which

accurately produces

perfect cutting edges

and extraordinary sur-

face qualities of up to Ra =

0.1 μm when machining PCD

tools. It is quite impressive:

The HELITRONIC POWER

DIAMOND achieves only minimum

stock removal rates due to a fi ne ad-

justment of power during the erosion

process. The result is PCD cutting

edges with perfect surface quality and

greatly improved chip resistance.

Workpieces manufactured in this way

now almost achieve the quality of

ground PCD tools.

WALTER HELITRONIC POWER DIAMOND

Only the cutting edge countsThe two-in-one concept of the WALTER HELITRONIC POWER DIAMOND offers a risk-free entry into the PCD business.

+++ c h r i s t o p h . e h r l e r @ w a l t e r - m a c h i n e s . d e

+++ w w w . w a l t e r - m a c h i n e s . d e +++

FURTHER INFORMATION

[1][1]

Immaculate: [1] The improved cutting edge quality is clearly visible [2] Edge rounding of

3.9 μm at the PCD tool cutting edge

Head-turner: The changer is loaded with up to 24

grinding wheels

Superior

quality: PCD step

drill and carbide

full-radius milling

cutter with perfect

surface quality

[2][2]

STAND


28 MOTION 01/09


WALTER HELITRONIC ToolStudio

The easy way to produce a toolThe new version of the HELITRONIC ToolStudio grinding software from WALTER is even more effi cient and simplifi es grinding of complex tool geometries.

ter how small, the tool can be individually tailored. Further key functions:

‘Click & Edit’: Simply click on the 3D simulation to see the relevant

geometries and technology parameters

Time saving: Path-optimized calculation of positioning movements

between operations and cutting edges

Safety: Automatic collision check prior to manufacture

Tool design made easy

The modular design of the new version of HELITRONIC ToolStudio permits

variable and individual configuration of all important parameters. Using the

modular principle, any number of operations can be added or copied – a huge

advantage when designing tools. All this extra flexibility comes in handy when

processing step tools (for example step drills or stepped milling cutters).

WALTER has improved the tool wizard for step tools so that it can now be re-

started at any time even after manually adding or copying individual operations.

The amount of work required by the operator has been considerably reduced;

with just a few clicks he can replace an existing drill cutting edge on a special-

ized step drill.

Only a few years ago, tools with

variable helix angles, uneven in-

dexing between the individual cutting

edges and constant flute width across

the body were categorized as special

tools. Nowadays, complex geometries

such as these are becoming part of the

bread-and-butter work of many tool

manufacturers and resharpening com-

panies. HELITRONIC ToolStudio is the

efficient software package for the

HELITRONIC tool grinding machine

series from WALTER. It covers every

aspect of the configuration of tool ge-

ometries.

Minimal effort

Using the integrated wizard technol-

ogy, tools can be modeled in a simple

way. The required data input is reduced

to a minimum. The system only re-

quests the most important tool param-

eters and automatically runs through

the necessary input screens. At the

same time the HELITRONIC ToolStudio

software accesses WALTER’s knowl-

edge database which stores important

tool grinding experience and helps to

fi nd a speedy solution for all produc-

tion tasks. The software complements

the entries with relevant geometry and

technology parameters such as grin-

ding wheel sets and grinding feed

rates, for example. Based on the basic

tool model created and high-precision

3D simulation which is updated for

each and every modifi cation – no mat-

High precision 3D view: Graphic tool simulation with HELITRONIC ToolStudio

STAND


29MOTION 01/09

tribution of measuring points can be freely confi gured. While the tool param-

eters are being defi ned, the HELITRONIC ToolStudio software calculates the

fl ute shape with specifi c focus on all the determining factors. The path of the

helical angle, the radius of the grinding wheel bond or the angle of the grinding

wheel are just some examples. Time-consuming checking of the fl ute shape is

not required. Accurately parallel clearance angles and land widths on the step

are produced without the need for long-winded manual corrections. The capa-

bility of the HELITRONIC ToolStudio

software is unrivaled in the market

for grinding software. Visitors to

Stand 17 can see for themselves.

Useful touch functions

In the production of step tools on

WALTER machines two particular prob-

ing functions of the software are very

helpful. One serves in the alignment of

coolant holes and measures the con-

centricity of the blank. The other scans

the fl ute path along the contour of the

tool. It is possible to check individual

diameters or steps as well as entire

profi le contours in this way. The dis-

Replaced with a few clicks: Drill cutting edge using the example of a special tool

with variable helix design and two steps

Virtual probing: HELITRONIC ToolStudio records individual diameters and steps as

well as the entire profi le contour

+++ c h r i s t o p h .e h r l e r @ w a l t e r- m a c h i n e s .d e

+++ w w w.w a l t e r- m a c h i n e s .d e +++

FURTHER INFORMATION


The global economy in recession – expertise and technological leadership secure exports of high-quality capital equipment even in times of crisis.

Sucked into the recession: Key industries like the

automotive sector have been affected

of the recession. The automotive industry, machine construction and the electron-ics industry are particularly severely affected.

From product manufacturer to systems provider

However, there is one piece of good news amidst all the doom and gloom: the global economic crisis fi nds German and Swiss industry in a comparatively sta-ble condition. In recent years, many fi rms in both countries have undergone a unique transformation from product manufacturer to systems provider. Instead of just selling machines, electronic devices or vehicles, they are now selling end-to-end, innovative solutions with an industrial core packaged in a wide range of upstream and downstream services – from planning and organization to manage-ment, operation, fi nancing, insurance, maintenance and modernization. German and Swiss companies have become global market leaders in many industries, offering very attractive high-quality, all-round packages of products and ser-

T here is no doubt that the global economy is in a crisis. What is un-

certain is how long the recession will last and how deeply it will affect indi-vidual economies. The bad economic tidings of recent months do not provide much hope because, for the fi rst time in decades, the slowdown is affecting the whole world at the same time. Even emerging economies and exporters of raw material are facing diffi cult times. The crisis on the fi nancial market has become a global economic crisis. Where-as at the beginning it affected only a few isolated sectors like the lending busi-ness, now there are hardly any areas that are not being sucked into the whirlpool

Lec ture I -1 | May 6 , 20 09 | 14 .0 0

Production in the global economic climate

M A R K E T S & T R E N DS

30 MOTION 01/09

By Prof. Thomas Straubhaar

L_Vortrag_I1_Straubhaar_E.indd 30 09.04.2009 15:32:13 Uhr

vices. It is not so much low costs and prices that give them their competitive advantage. Instead, it is their effective organization and effi cient management of complex international value creation networks that give them a monopoly position that goes beyond cost leader-ship. Technological leadership enables them to set the rules and to charge high prices with generous margins. It makes local fi rms less susceptible to short-term economic problems. This means that many German and Swiss fi rms are not attempting to offer cheaper prod-ucts and services than the internation-al competition. Their aim is to be tech-nological leaders, both now and in the future. Technological leaders are not as involved in the cut-throat international price competition and are not as exclu-sively cost-dependent. They set their own prices. This means that they re-main internationally competitive and can sell their products and services even in times of moderate to serious economic diffi culty.

The future of the

global economy

The global recession will pass, hope-fully sooner rather than later. Neverthe-less, it is the cause of increasing uncer-tainty: Will the global economy be the same after the recession? Does theglobal economic crisis spell the end of globalization? Globalization has swept across the world like a hurricane in the last twenty years. Protective fences and

[2][2]

iron curtains have been pulled down and national borders swept away. Interna-tional division of labor and specialization have acquired a new, global dimension. The links in the value chain have been broken down into smaller and smaller units and distributed all over the world. ‘As long as it’s cheap’ became the guiding principle. It seemed as if everything was possible. The Earth was reduced to a fl at disk. Long distances and the associated costs apparently no longer played a part in the new economic geography. Is the crisis on the fi nancial market and the global recession leading to a re-versal of this trend? Has the international division of labor passed its peak? Are high export growth rates a thing of the past? And will we now return increas-ingly to local rather than global production? It almost looks like it. International sales have collapsed. Emerging economies are facing a lack of demand for their consumer goods and raw materials and therefore do not have the money to go shopping on the world markets. The absence of power in the American growth engine is putting the brakes on economic growth worldwide. This is particularly true of Southeast Asia and Latin America, regions in which production is heavily dependent on the U.S. market.Despite all the economic trouble spots, there are enough grounds for optimism for German and Swiss industry. This view is supported by the German and Swiss fi rms’ high level of expertise and technological leadership. Small and medium-sized companies in these countries continue to be favorably positioned with a tendency towards process-oriented rather than product-oriented innovations. Expertise and technological leadership secure exports of high-quality capital equipment, par-ticularly in times of economic diffi culty. Demand for infrastructure investment, capital equipment, ma-chinery, devices and ap-pliances in the emerging economies of Southeast Asia, the oil-exporting nations of the Arab world and the new EU coun-tries of Central and Eas-tern Europe will continue – despite, during and aft-er the fi nancial crisis. German and Swiss fi rms will soon start to benefi t from it again.

31MOTION 01/09

ABOUT THE SPEAKER

Prof. Thomas Straubhaar has been Director of the Hamburg Institute of International Economics (HWWI) since 2005. His key research areas include international economic relations, economic framework policy, economics of education and population economics

THE WHOLE WORLD IS AFFECTED SOLUTIONS TO THE CRISIS

What does the future hold? [1] For the fi rst time in decades the slowdown is affecting the whole world simultaneously [2] There are many factors infl uencing the

economic equilibrium. Expertise and technological leadership secure exports of high-quality capital equipment, particularly in times of economic diffi culty

10810610410210098969492

98 99 00 01 02 03 04 05 06 07 08 09

Slowdown in the OECD countries

1101081061041021009896949290

98 99 00 01 02 03 04 05 06 07 08 09

Slowdown in the USA

115

110

105

100

95

90

8598 99 00 01 02 03 04 05 06 07 08 09

Slowdown in China

The psychology of expectations

10810610410210098969492

98 99 00 01 02 03 04 05 06 07 08 09

Slowdown in the euro zone

[1][1]

EmploymentPrice level

Monetary policy

Fiscal policy Labor market policy

Foreign trade policy

Stability goals

Sou

rce:

OE

CD

L_Vortrag_I1_Straubhaar_E.indd 31 09.04.2009 15:32:15 Uhr

32 MOTION 01/09


resources assigned to specifi c operations largely determine the fl exibility and

suitability for innovation of manufacturing processes. The greater this commit-

ment, the higher the quantitative performance and process reliability that can be

achieved. However, there is also the risk that the required values cannot be reached

by changing the components or processing conditions. Therefore sustainable

process design must also integrate new technology into existing process chains

quickly and reliably.

Potential for development

Process improvements depend on three factors, innovative machine technology,

new developments in grinding and dressing tools and improved process condi-

tions. The effi cient introduction of new techniques requires an in-depth knowl-

edge of the effective relationships in the grinding process. Only when the inter-

Conventional processes in grinding

technology are under constant pres-

sure to improve still further in answer to

the increasing performance of alterna-

tive cutting techniques. What we see is

that on the one hand, processes with

geometrically determined cutting are

competitive in the fi elds of cylindrical,

surface and profi le machining because

they have great fl exibility, high metal

removal rates and low consumption of

resources. On the other hand, the poten-

tial offered by metal removing pro-

cesses is their high process reliability

when machining complex contours to

the highest quality specifi cations.

Sustainable production

The delicate balance between output

and precision provides an opportunity

for grinding technology. Against a back-

ground of runaway proliferation of tech-

nological innovations, there are com-

petitive advantages that do not depend

on performance and precision alone.

Future manufacturing strategies will

only be successful in the long term if

they save valuable resources and can

react fl exibly to changing technical and

economic constraints. Only innovative

companies that are the fastest to imple-

ment new results from research and

development will be competitive in the

world markets of the future. The capital

Grinding processes are a delicate balance of high precision and high output.

Opportunities for grinding

technology: Technologi-

cal innovations secure

competitive advantages

Lec ture I -2 | May 6 , 20 09 | 14 .45

Precision machining, quo vadis?

By Prof. Eckart Uhlmann

L_Vortrag_I2_Uhlmann_E.indd 32 15.04.2009 14:04:02 Uhr

33MOTION 01/09

wheels without slots and do not increase the thermal stresses on the workpiece.

The slotting causes modulation of the machining forces and thus dynamic

excitation of the grinding process. This excitation only leads to process instability

if the speed ratio of the grinding wheel to the workpiece, multiplied by the number

of grooves, comes to a whole number. For all other speed ratios, although the

grooving causes greater oscillation amplitudes than are obtained with ungrooved

grinding tools, they have no signifi cant effect on roughness and roundness when

used in machines that have high dynamic rigidity.

In rapid stroke profi le grinding of materials that are diffi cult to machine, such as

high-performance ceramic and nickel-based alloys, there are currently two chal-

lenges to be faced. These are the analysis and implementation of the interaction

between kinematic parameters, coolant conditions and the grinding wheel spec-

ifi cation. Because the grinding energies are lower it is possible to perform rap-

id stroke grinding with a reduced coolant requirement at high metal removal

rates and with a low level of damage. However, it is only possible to achieve

suffi ciently true profi les if the combination of the thermal and mechanical stres-

ses in the critical zone leads to microcrystalline splitting of the abrasive grit.

Grinding wheel design therefore depends on full knowledge of the mechanical

fracturing and tribological properties of innovative abrasive grits.

Here, too, system-

atic analysis of the

potential applica-

tions of innovative

products makes a

signifi cant contri-

bution in combina-

tion with techno-

logical studies and

ever more powerful

modeling tech-

niques.

actions between the machine, the tool

and the process are known can the en-

gineer combine the solutions offered

by the wealth of innovations on the

market with maximum development

potential. He is supported by innovative

process models from research and de-

velopment. An example is the explicit

modeling of process conditions and

their effects on the grinding process.

What is the effect on process parameters

and the work result in external cylindri-

cal plunge grinding if slots are made in

the grinding wheels at certain locations?

A research project that is currently un-

derway at the Institute for Machine Tools

and Factory Management (IWF) at Berlin

University of Technology is investigating

this very question. The purpose of the

research is to be able to specify the ef-

fective relationships explicitly. To do this,

the interaction between the tool and the

workpiece has been modeled in such a

way as to use numeric simulation to

quantify the thermal fl ow density in the

workpiece for various groove confi gura-

tions and process parameters.

Industrial application

Slotted grinding wheels produce a

higher metal removal rate than grinding

ABOUT THE SPEAKER

Prof. Eckart Uhlmann is Head of the Fraunhofer Institute for Production Systems and Design Technology (IPK) in Berlin and holds the Chair of Machine Tools and Factory Management at the Institute for Machine Tools and Factory Management (IWF) at Berlin University of Technology

Informative: Slotted grinding wheels produce a higher metal removal rate than grinding wheels without slots

and do not increase the thermal stresses on the workpiece

Rapid stroke grinding: This gives high metal removal

rates with a low level of damage

Single-crystal corundum

Sintered corundumae = 12 μmvc = 80 m/s

1600

˚C

1200

1000

8005 10 15 mm3/mms 25 5 10 15 mm3/mms 25

40

%

20

10

0

100

J

mm3

50

25

0

Related metal removal rate Q‘w

without grooves

Max

imum

wor

kpie

ce

tem

pera

ture

Poss

ible

incr

ease

in m

etal

re

mov

al ra

te

Spec

ifi c

grin

ding

ene

rgy

Table feed rate Vft

groove width 15 mm

EXTERNAL CYLINDRICAL PLUNGE GRINDING

Workpiece: 100Cr6 (60 HRC); Grinding wheel: B126 V360RAPID STROKE GRINDING OF A

NICKEL-BASED ALLOY

groove width 5 mm

40 80 120 m/min 200

L_Vortrag_I2_Uhlmann_E.indd 33 15.04.2009 14:04:04 Uhr

34 MOTION 01/09


conventional emulsions and oils in surface grinding and external cylindrical

grinding. In this context, the grinding forces encountered, the workpiece surface

roughness, the grinding wheel wear and the temperature of the material subject

to material removal rate and cooling lubricant were examined.

Polymer-based cooling lubricants

The researchers ground a nickel-based alloy on a surface grinding machine for

the basic experiments with polymer-based cooling lubricant. The variables

consisted of the material removal rate and the viscosity of the cooling lubricant.

Comparison measurements were carried out using a six per cent mineral oil-

in-water emulsion. In all experiments, the coolant was supplied by an open jet

nozzle with extended jet. Coolant pressure and coolant amount remained un-

changed. The experiments showed that the preset viscosity of the polymer

lubricant largely determines process forces, grinding temperatures and work-

piece surface roughness. Increasing the viscosity resulted in a reduction of the

process forces generated and minimized the grinding wheel wear slightly. How-

So far, all attempts at substituting

cooling lubricants in grinding have

failed. Due to the high temperatures pro-

duced during the grinding process it is

not yet possible to abandon them. On

the contrary, the multitude of grinding

applications is constantly posing new

challenges to the range and design of

coolant systems. Optimum process re-

sults in terms of profi le accuracy, grind-

ing wheel life and minimum processing

times can only be achieved if compo-

nent, tool, process parameters and cool-

ing conditions are coordinated.

The Institute for Machine Tools and

Production Technology (IWF) of Bruns-

wick Technical University studies the

suitability of polymer-based lubricants

and liquid nitrate as an alternative to

Lec ture I -3 | May 6 , 20 09 | 15 .30

Cool and greasyThe Institute for Machine Tools and Production Technology (IWF) at Brunswick Technical University has researched new approaches for effective cooling and lubricating.

Process: surface grinding with the creep feed methodCooling lubricant: emulsion – Hysol RD 6%, Castrol Polymer A – Viscosity 1 mm2/s Polymer B – Viscosity 2.3 mm2/s Polymer C – Viscosity 6.5 mm2/sQuantity of cooling lubricant: 190 l/min, open jet nozzle

Material: Inconel 718ae = 0.5 mm aed = 0.8 μm/Uap = 16 mm qd = 0.8 +vc = 35 m/sVw = 125 mm3/mm

Grinding Wheel: 89A 60 H 9AV 55

Conclusive: Grinding temperatures measured with thermal elements show a decrease in grinding temperatures with increasing material removal rates

By Dr Hans-Werner Hoffmeister

400

˚C

300

250

200

150

100

50

00 5 10 15 mm3/mms 25

Specifi c material removal rate Q’w

Emulsion – Hysol RD 6%Polymer A – Viscosity 1 mm2/sPolymer B – Viscosity 2.3 mm2/sPolymer C – Viscosity 6.5 mm2/s

L_Vortrag_I3_Hoffmeister_E.indd 34 09.04.2009 17:27:30 Uhr

35MOTION 01/09

removal. Lower grinding axial forces had a positive effect on the dynamic and

static resilience in grinding, resulting in repeatable grinding behavior.

Liquid nitrogen

For the effi cient removal of the grinding temperature from the contact zone, the

team from IWF worked with liquid nitrogen and minimal quantity lubrication as

an experiment. In order to be able to discuss the pure cooling effect better,

comparison tests were made with dry grinding. Special jets were used to sup-

ply the nitrogen and the oil mist from the minimal lubrication system into the

contact zone (see picture above). The liquid nitrogen had to be conveyed di-

rectly into the contact zone through an insulated pipe.

As expected, the liquid nitrogen reduced the grinding temperature consider-

ably compared to dry grinding. Yet no definite improvements could be achieved

compared with emulsion cooling. Under the same grinding conditions thermal

interaction of the workpiece edge restricted the material removal conditions

for emulsion as well as for liquid nitrogen lubrication. Liquid nitrogen lacks

any kind of lubricating effect. During the course of the experiments it became

evident that the combination with minimal quantities of mineral oil got the best

results in respect of grinding

wheel wear and unaffected

workpiece edge. The current

price of liquid nitrogen, how-

ever, and the complex design of

jets and suction devices in the

machines prohibit industrial ap-

plication at the moment. But we

can be sure to expect more in-

teresting results about polymer

lubricants in the future.

ever, the quantity of heat transferred

to the workpiece increases at the same

time. Here, a compromise between re-

ducing the grinding temperatures and

grinding wheel wear has to be found,

depending on process line-up and job

specifi cation. Evidently, the viscosity

has no bearing on the surface quality

when surface grinding. The research-

ers noticed a slight improvement with

external cylindrical grinding. Here, the

cooling lubricant was also supplied via

an open jet nozzle and was not changed

during the series of experiments. The

variation in material removal rate clear-

ly shows a connection between in-

creased output and increased material

removal rate. The idea of reducing

grinding wheel wear signifi cantly with

high viscosity index polymer lubricants

was unsuccessful, however.

All in all, the grinding wheel wear was

so small for all the material removal rates

processed that there was no difference

between polymer cooling lubricant and

emulsion. However, the polymer cooling

lubricant reduced the grinding tangential

force and lowered the grinding output

of the machine spindles required for chip

Comparison tests with dry grinding: Special jets convey the nitrogen and the oil mist from the minimal lubrication system to the

contact zone

Grinding wheel Dressing roll

Nitrogen jet

MMS jets

Insulated cryogenic pipeForce measuring table

ABOUT THE SPEAKER

Dr Hans-Werner Hoff-meister is Deputy Director of the Institute for Machine Tools and Production Technology (IWF) at Brunswick Technical University

L_Vortrag_I3_Hoffmeister_E.indd 35 09.04.2009 17:27:30 Uhr

36 MOTION 01/09

Lec ture I - 4 | May 6 , 20 09 | 16 .15

Small cause – big effect


Round is not necessarily round: The knowledge of interaction of dynamic process variables is a fundamental prerequisite for optimum adjustment of the grinding wheel.By Johann Noichl

the opposite direction without the support, the dressing forces caused the thin,

unsupported diamond plate to vibrate. The vibrations were transmitted to the

grinding wheel, and were manifested as spirally-shaped chatter marks on the

workpiece. Dressing had in fact not produced a round grinding wheel, but a

polygon with numerous microscopic facets caused by the vibrations.

Ceramic-bonded CBN

Micro-facets also occurred when dressing ceramic CBN grinding wheels with a

rotating diamond form roll. In the experiment, the grinding wheels were profi led

at a peripheral speed of 60 m/s and put to work creep-feed grinding on a nickel

The effect of the dressing of grin-

ding wheels on the workpiece has

already been investigated many times,

and often extremely scientifically.

These investigations have usually been

carried out under laboratory condi-

tions, which is why the interactions

which arise during dressing between

dressing tool, grinding wheel, grinding

machine and the setting parameters

of the process have not always been

adequately taken into account. Their

effects on the grinding results and the

potential for process optimization have

recently been investigated by the WZL

Aachen in collaboration with TYROLIT

Schleifmittelwerke Swarovski on ce-

ramic-bonded corundum and CBN

grinding wheels.

Ceramic-bonded corundum

In preparation for an external cylindrical

grinding operation, a ceramic-bonded

corundum grinding wheel was dressed

with an upright diamond dressing plate.

The grinding results were not impres-

sive. Despite maintaining set constant

process variables, it was impossible to

produce a clean workpiece surface. As

it turned out, the feed direction of the

diamond plate had a decisive infl uence

on the surface quality of the workpiece:

when the diamond dressing plate was

supported by the dresser support dur-

ing transit of the grinding wheel, there

were no chatter marks on the work-

piece. Where the diamond rotated in Modal analysis: The process recognizes high resonant vibrations and contributes to a reduction in wheel

wear and improvement in the workpiece surface

Frequency =̂ speed of the dressing roll

Grinding wheel: n = 0 Roll: n varies

150

90

60

30

0

0 100 Hz 200 0 20 40 60 80 Hz 100

F dyn F dyny y

x xz z

85 Hz =̂ 40m/s

150 Hz

Dyn

amic

fl ex

ibili

ty

60 m/s

40 m/s 40 m/s

80 m/s

Frequency =̂ speed of the grinding wheel

L_Vortrag_I4_Noichl_E.indd 36 09.04.2009 17:28:39 Uhr

37MOTION 01/09

[1][1] [2][2]

increase in speed. The realization of these ideas makes very great demands on

the grinding machines in terms of their dynamic rigidity. On top of this, the dia-

mond dressing rolls will have to be used at much higher speeds. This has prompt-

ed the question of whether it would be possible to dress a CBN grinding wheel

at a lower peripheral speed and then to use it at high cutting speeds. This how-

ever is not possible due to the dimensional error arising as a result of the radial

expansion of the grinding wheel.

The ideal relationship between the peripheral speed of the dressing roll and that

of the grinding wheel should be in the region of 0.8. In this way we obtain a rough

wheel surface. This in turn gives good grinding performance and an acceptable

service life for the diamond dressing roll. The use of this dressing speed ratio at

high cutting speeds also requires dressing units with very high spindle speeds.

Surprising result

Now however there has been a surprising result from another experiment with

ceramic CBN wheels. When creep feed grinding hardened ball-bearing steel on the

Blohm AGNETA speed-stroke grinding machine, it was even possible to grind the

workpiece at a cut-

ting speed of 200

m/s and a very low

dressing speed ra-

tio of 0.4 without

causing it any ther-

mal damage. This

result requires fur-

ther verifi cation,

but does indicate

that there is poten-

tial regarding prac-

tical realization.

alloy at a cutting speed of 80 m/s. With

this process setting it was quite impos-

sible, irrespective of the grinding wheel

specifi cation, to produce an accepta-

ble surface on the workpiece. It was

extremely rough and wear on the grin-

ding wheel was extremely high. A mo-

dal analysis of the grinding machine

revealed that both the selected speed

of the dressing form roll and the speed

of the grinding wheel lay within the

range of resonance of the grinding ma-

chine. Because of the resonance of the

grinding machine itself, the dressing

roll produced a polygonal grinding

wheel. When grinding, the micro-facets

broke up and thus generated a high rate

of wear in the grinding wheels and a

poor surface to the workpiece. The so-

lution was to use a dressing speed of

80 m/s. This prevented the resonant

vibrations, and the grinding results

improved immediately.

Higher speed

In practice, ceramic-bonded CBN grin-

ding wheels are normally used at cut-

ting speeds of up to 150 m/s. Efforts

are being made, however, to increase

machining performance by a further

ABOUT THE SPEAKER

Johann Noichl is Manager, Application Technology and in charge of the test center in the precision grinding sector at the Aus-trian Tyrolit Schleifmittelwerke Swarovski KG. Trained as an electrical engineer at the HTL Innsbruck, he has worked since 1974 for TYROLIT in the trials, application technology and marketing sector

[1] Supported: A diamond plate dresses a ceramic-bonded corundum grinding wheel [2] Unsupported: Resonant vibrations from the grinding machine are transmitted

to the workpiece in the form of spiral chatter marks

L_Vortrag_I4_Noichl_E.indd 37 09.04.2009 17:28:40 Uhr

38 MOTION 01/09


cess. The principle of the technique consists of adding high-frequency (16–40 kHz)

oscillations at amplitudes of two to 30 μm in or transverse to the direction of infeed.

In this way, the use of ultrasonics has the effect of signifi cantly reducing feed power,

chip size, wear on the tools and heat generation, and it also improves the quality

of the surface. The ultrasonic oscillations reduce the friction between the chip and

the cutting face of the tool. This leads to thinner chips and thereby to a reduction

in the cutting force and an improved surface fi nish when grinding.

To investigate ultrasonic-assisted grinding, Professor Tawakoli and his team de-

Experiments carried out at the Center

of Competence for Abrasive Tech-

nologies and Precision Workmanship

(KSF) at Furtwangen University of Ap-

plied Sciences demonstrate that ultra-

sonic assistance can optimize processes

when cutting metal with geometrically

defi ned or with geometrically undefi ned

cutting edges. Compared with conven-

tional processes, ultrasonically-assisted

grinding and dressing is a hybrid pro-

Dressing with a static dressing tool and with a rotating form roll

Dressing plate

Single-point dressing diamond

Cup dresser Dressing roll

Ultrasonic-assisted dressing with static dressing tools Ultrasonic-assisted dressing with rotating dressing tools

Grinding wheel

Lec ture I I -1 | May 7, 20 09 | 9 .30

Grinding and dressing with ultrasonics

Additional high-frequency oscillations in the ultrasonic range during grinding and dressing reduce forces, temperature and the wear on tools – and enhance the surface fi nish.

Nature as an example: The

use of ultrasonic amplitudes

optimizes grinding processes

Comparison: Using a static dressing tool, ultrasonic assistance can be integrated relatively easily. Using a rotating dressing tool, as is the case with the form roll, it is

more complicated and calls for both know-how and more complex calculations and equipment

By Prof. Taghi Tawakoli

L_Vortrag_II1_Tawakoli_E.indd 38 09.04.2009 17:31:46 Uhr

39MOTION 01/09

Piezoceramic

converter Booster Sonotrode Workpiece

Dynamometer

face of the grain. However, this smooth surface does not have the ideal gripping

properties for creating chips. In ultrasonic-assisted grinding the grains are broken

into fi ne particles by the low-amplitude ultrasonic oscillations, but not smoothed

out. The small sharp fractures on the contact surface of the grain increase its cut-

ting performance in grinding and this led to 30 to 50 per cent reduction in the

grinding power required in the experiments. In comparison with conventional

dressing the additional high-frequency motion of the dressing tool against the

grinding wheel in the micrometer range is characteristic of ultrasonic assisted

machining. In general, it is relatively easy to integrate ultrasonic assistance with a

static dressing tool. By contrast, it is more complicated with a rotating dressing

tool, such as a form roll, calling for both know-how and more complex calculations

and equipment.

Advantages in grinding and dressing

Grinding power is reduced by 30 to 50 per cent

Improved surface fi nish, reduction of the Rz values by 30 to 50 per cent

The surface structure has a different appearance and a higher contact area ratio

Lower temperatures on the surface

Optimized chip formation process with shorter chips

Less wear to the dressing tools

Better profi le retention

Reduction in grinding power and temperatures

veloped an addressable workpiece

holder. The ultrasonic oscillation chain

consists of a piezoceramic converter, a

booster, a sonotrode and a special work-

piece clamping device (see picture

right). The ultrasonic generator converts

electric current into high-frequency

pulses, which are then converted by a

piezoceramic converter into mechan-

ical oscillations with an ultrasonic fre-

quency of 21 kHz. The sonic amplitude

is amplifi ed by the booster and then by

the sonotrode and is transmitted to the

workpiece, which is connected to the

sonotrode. The resultant oscillations of

the workpiece in the tool-holder reach

an amplitude of between ten and 30 μm

at a frequency of about 21 kHz.

Inspecting the grinding

In numerous inspections of work with a

variety of tools, grinding wheels and

stock, the research team compared

ultrasonic-assisted fl at grinding using

traditional corundum grinding wheels

with conventional fl at grinding. Burn

marks were produced in conventional

grinding. In contrast, the workpiece

ground with ultrasonic assistance dis-

played no sign of thermal damage. The

high-frequency interaction between the

active grains and the high acceleration

of the workpiece in ultrasonic-assisted

grinding simplifi es the material remov-

al process. Chips are more easily re-

moved because micro-cracks in the

contact zone between the grains and the

workpiece propagate more quickly as a

result of the impacts due to oscillation

and positively infl uence the next chip

formation. This reduces grinding forces

and frictional effects. There is less plas-

tic deformation in the contact zone. In

addition, the ultrasonic assistance has

a benefi cial effect on the fi nished sur-

face of the workpiece. It is fi ner and has

a higher contact area ratio.

The KSF researchers achieved similar

positive results with ultrasonically-as-

sisted dressing of conventional and CBN

grinding wheels. With conventional

dressing, the tool smooths out the sur-

ABOUT THE SPEAKER

Prof. Taghi Tawakoli is founder and head of the Center of Competence for Abrasive Technologies and Precision Workman-ship (KSF) at Furtwangen University of Applied Sciences. Prof. Tawakoli has over 130 published papers and six patents to his credit and has a laboratory ideally equipped for research in the areas of grinding technology, superfi nishing, mass fi nishing, cutting of hard materials and milling

Ultrasonic oscillation chain: Example of an experimental set-up

L_Vortrag_II1_Tawakoli_E.indd 39 09.04.2009 17:31:52 Uhr

40 MOTION 01/09


curacy. The implications are high procurement costs and long downtimes for

installation and set-up. A joint project between BLOHM JUNG and Georg-Simon-

Ohm University in Nuremberg comes up with a new approach on how accurate

grinding results can be achieved even with worn dressing tools by using mea-

surement control.

Correction of the tool radius

For contour controlled grinding wheel profi ling with diamonds, a CAD/CAM

system, such as the GRIPS 32 programming system, normally produces the NC

program for the desired grinding wheel profi le. The radius of the dressing tool

is taken into account by the so-called tool radius correction. For dressing sys-

tems with swiveling axis the pivoting angle of the dresser must also be observed

so that correct tool intervention is always guaranteed. If the dressing tool is

worn, the original diamond radius takes on an irregular and blunt shape. The

tool radius correction performed by the control unit which always uses the

ideal unworn diamond radius will lose its effectiveness, resulting in dressing

and processing errors. A dedicated tool correction facility in the NC program

takes tool wear into consideration and ensures that a consistently high level of

process quality is maintained. The direct advantages of this kind of wear com-

pensation are:

In profi le grinding, dressing tools

sharpen the grinding wheel and pro-

duce the desired grinding wheel pro-

fi le. Fixed and rotating diamond tools

are used for this process, particularly

for small lot sizes and reprofi ling of

grinding wheels. These tools are inte-

grated in dressing systems which can

feature up to three CNC axes. Dressing

systems which allow the dressing tool

to swivel around the center of the dia-

mond radius are of particular benefi t.

They enable complicated profi les to be

dressed by a single dressing tool with-

out colliding.

In time, the radius of the diamond cut-

ting edge will wear as a result of grin-

ding wheel dressing. It will lose its ge-

ometry. This geometry error transfers

to the grinding wheel and consequent-

ly to the workpiece. Only regular re-

placement of the dressing tool will

therefore guarantee high process ac-

Lec ture I I -2 | May 7, 20 09 | 10 .15

Compensating professionally

[1][1] [2][2]

[1] Pivoting angle: Requirements for intervention between dressing tool and grinding wheel (R tool radius, pivoting angle, pressure angle)

[2] Wear compensation: For contour-accurate dressing a correcting motion of the dressing tool on three axes (a, b, c) is required

Even worn dressing tools can accomplish accurate grinding tasks, as long as exactmeasuring of the tool cutting edge compensates tool errors directly. By Prof. Wilhelm Schröder

L_Vortrag_II2_Schro der_E.indd 40 09.04.2009 17:33:03 Uhr

41MOTION 01/09

aligned with the dressing contour. The effectiveness of the wear compensation

is increased and the potential of dressing systems with swivel axis is com-

pletely utilized.

Grinding experiments

The functionality of the compensation procedure has been proven by several

grinding experiments. To this end, a grinding wheel was profi led with a 2mm

radius whereby the worn diamond rotates from –30 degrees to +30 degrees.

Through this particular dressing movement the diamond cutting edge is mir-

rored onto the grinding wheel during the dressing process. At the same time,

the calculated wear compensation compensates for every error on the dressing

diamond. Checking the dressing results on a visual coordinate measuring ma-

chine shows that a contour accuracy within the tolerance range of ±2,5μm has

been achieved in spite of the diamond wear and the off-center diamond posi-

tion. If the same experiment is carried out without wear compensation, the

deviation clearly exceeds ±5μm.

Conclusion

Modern control technology facilitates continued use of diamond tools for highly

accurate grinding tasks, even

if they are worn. The service

life of the dressing tools is

therefore extended and at

the same time the grinding

process is stabilized by com-

pensating for the dressing

wear. As a consequence, us-

ers have been given access

to a hitherto untapped poten-

tial for cost reduction and

quality improvement.

Stabilization of process

control

Increase of process accuracy

Increased service life

Minimum downtime

Lowering of procurement costs

In order to be able to compensate the

wear of the dressing tool, the exact

geometry of the diamond cutting edge

must be known. For this purpose, the

dressing diamond is automatically

measured by a measuring probe. With

this reading, the actual shape of the

diamond cutting edge is calculated by

a mathematical process and the form

deviation is made available through the

control. The grinding wheel profi le is

only dressed accurately if the diamond

with its worn cutting edge is aligned

in such a way that grinding wheel and

diamond have a common tangent at

the desired intervention point. At the

same time, the radius deviation has to

be radially compensated on two linear

axes. Wear compensation therefore

requires a correcting motion by three

CNC axes. This shows the distinct ad-

vantage of dressing systems with

swivel axes. The swivelability enables

the worn dressing tool to be perfectly

ABOUT THE SPEAKER

Prof. Wilhelm Schröder is professor at the Georg-Simon-Ohm University in Nuremberg, where he is responsible for the fi elds of Engineering Mechanics, Machine Dynamics and Machine Elements in the Mechanical Engineering Faculty

Accurate dedication to contour: Innovative measuring of dressing diamonds reduces set-up times and increases accuracy

L_Vortrag_II2_Schro der_E.indd 41 09.04.2009 17:33:04 Uhr

42 MOTION 01/09


knowledge about the interactions between process and machine requires long

iteration loops when setting up new processes. Understanding the causes of vibra-

tion phenomena and the prediction of interactions help with the systematic im-

provement of manufacturing processes and machines and support effi cient and

effective design of the production process.

Modeling approach for pendulum and high-speed grinding

The approach chosen for the analysis and prediction of process-machine-inter-

actions in pendulum and high-speed grinding processes assembles the complete

model in two parts. On the one hand, we examine the process regarding the

forces generated during chip removal which are changing continuously. On the

other hand, the machine structure is reacting dynam-

ically to the stimulation. Initially, the models for pro-

cess and machine are built separately and are later

linked by suitable parameters. The key infl uencing

factors are identifi ed; generated forces are calculated

and transferred to a suitable machine model. This

model calculates the displacement of the grinding

wheel with the aid of the stored dynamic characteris-

tics of the machine. The positional deviation is then

transferred to the process model. The next calculation

step takes the modifi ed process conditions into con-

sideration when calculating the dynamic forces of the

process model.

High-speed grinding is characterized by high table

feed rates and low depth of cut, resulting in a large

number of overruns, frequent, very short run-in and

run-out periods and consequently a highly dynamic

performance of grinding forces. The run-in and run-

out periods must therefore be taken into account when

modeling. The transmission factors required for force

simulation are determined on the basis of experiment-

al test runs. In addition, different high-speed grinding

processes are carried out and generated forces, ac-

The German Research Foundation

(DFG) has launched a priority pro-

gram, with the aim of closing the know-

ledge gap regarding the infl uence on the

interaction between machine and proc-

ess. It focuses on the interactions at the

interface between structures and proc-

esses of technical systems. Within the

framework of the program, the WZL in

Aachen is also carrying out in-depth

research on innovative methods and

approaches for predicting the process-

machine-interactions in pendulum and

high-speed grinding processes. Missing

Linked: Key infl uencing factors are identifi ed, emerging forces are calculated

and transferred to a suitable machine model

Maschinensteifi gkeitMachine rigidity

Control cycles Grinding wheel

Machine model

Displacement

Cooling lubricant

Surface

Process parameters

Process model

Forces

Lec ture I I -3 | May 7, 20 09 | 11.0 0

Better understanding of grindingThe WZL (Laboratory for Machine Tools and Production Engineering) is taking part in a research program to predict the interactions between process and machine during grinding.By Dr Christoph Zeppenfeld

L_Vortrag_II3_Zeppenfeld_E.indd 42 09.04.2009 17:35:39 Uhr

43MOTION 01/09

chine characteristics in every operating point. The design of the model is based

on the machine’s CAD data. An FEM is generated through abstraction of machine

components and cross-linking the individual parts. The MBS machine model is

built by mapping of the feeding systems and is verifi ed by comparison with the

measured frequency of compliance operation of the machine. The machine

control reacts to positional deviation of the grinding spindle through induced

forces with a positional readjustment. In doing so, it also infl uences machine

dynamics signifi cantly. The model also takes this factor into consideration.

Conclusion and outlook

On the basis of the modeling method presented the dynamic performance of the

complete system of machine and process can be recorded and mapped over

longer travel distances. Looking at it from a holistic perspective can lead to a bet-

ter assessment of machining results, which can help to identify and avoid critical

processes prior to machining. Further research is still needed. One of the areas

we are currently

working on is fur-

ther detailing of the

models. We are also

expecting a marked

improvement in the

quality of prediction

with the implemen-

tation of additional

factors like cooling

lubricant and the

material to be pro-

cessed.

celeration and structure-borne sound

signals with a sample rate of 20 kHz are

recorded. The data obtained is evalu-

ated and stored in a simulation pro-

gram based in Matlab. Initial compari-

sons of the measured force paths

during run-in and run-out of the grin-

ding wheel using the assumptions

drawn up in the physical analytical

model show a good correlation be-

tween the simulated and measured

force path.

Machine models

Classic fi nite element models (FEM)

describe the behavior of machines in

only one operating point. High-speed

grinding involves long travel distances

with high speeds and accelerations. A

movable, fl exible multi-body simula-

tion model of the high-speed grinding

machine was therefore built for mod-

eling the machine. It is capable of cal-

culating the transmission of force from

movable bodies towards fi xed struc-

tural elements by division of force on

discrete nodes of the model. This ena-

bles the recording of the variable ma-

ABOUT THE SPEAKER

Christoph Zeppenfeld has been head of ‘Production Technology & License Support’ at MAN Diesel SE in Augsburg since January 2009. Until December 2008, he was manager of the Manufacturing Technology Research Area at the Laboratory for Machine Tools and Production Engineering at RWTH Aachen

Movable body

Linear guides

Workpiece table

Control loop z

Control loop y

Control loop x

Actual path New path

ILLUSTRATION OF MACHINE CONTROLMBS MODELSUB-ROUTINE FOR FLEXIBLE CONTACT FORCES

Linear drive with impulse decoupling

Contact forces

Components of the MBS machine model: The system calculates the transmission of force of movable bodies towards fi xed structural elements by division of force on

discrete nodes of the model

L_Vortrag_II3_Zeppenfeld_E.indd 43 09.04.2009 17:35:41 Uhr

44 MOTION 01/09

cosity of the medium and the operating pressure, which is between 3 and 180

bar depending on the application. The split is due to the difference between the

rotor thickness tolerance plus the number and the geometry of the vanes.

Demands on machines and tools

Vane pump and motor characteristics have a direct effect on effi cient process-

ing, as complying with lower component tolerances means more diffi cult, i.e.

more expensive manufacturing techniques. Christian Bauer GmbH + Co. KG of

Welzheim takes on the role of a consultant and specifi c requirements are care-

fully discussed with their customers. Following these discussions, the compo-

nent tolerances have to be increased occasionally.

For effi cient grinding of vane pumps and motors it is imperative that all deter-

mining production factors are examined in depth. It is also important that very

rigid machines are used where the natural frequency of machine and grinding

spindle is far outside the operating frequency range of the grinding process.

This holds true for all movable equipment. When choosing grinding tools, a

suitable abrasive layer must be selected depending on the workpiece and the

grinding material, with ducts for chip removal if necessary. In the past, Christian

Bauer has carried out much development work in order to increase part capac-

ity while at the same time maintaining better quality with regard to dimensions

Vane pumps and motors are dis-

placement devices. After intake,

the medium is enclosed in a defi ned

working chamber and is transported to

the consumer, i.e. piston, accumulator,

hydraulic motor or similar, on the pres-

sure side. During the entire working

stroke the vane is pushed against the

rotor ring by centrifugal force or a vane

ring. Theoretically, the pumped medi-

um cannot escape and the fl ow rate

stays almost constant across the adopt-

ed speed range. Adjusting the rotor ring

radially from zero eccentricity to max-

imum will vary the fl ow rate while keep-

ing the speed constant. This makes

vane pumps and motors clearly supe-

rior to other types of displacement ma-

chines. As rotors and vanes are moving

between two lateral cover panels and

are not allowed to touch, the result is

split fl ow. The fl ow loss is adversely

affected by the size of the split, the vis-

Lec ture I I - 4 | May 7, 20 09 | 11.45

Grinding of components for vane pumps

Manufacturing components for vane pumps and motors demands close machiningtolerances while keeping production costs low.By Dr August Kästner

L_Vortrag_II4_Ka stner_E.indd 44 09.04.2009 17:40:05 Uhr

45MOTION 01/09

Permanently high quality of grinding results

The machine’s response to temperature changes must be taken into considera-

tion if grinding results on a permanently high-quality level within the tolerance

range are to be expected. Appropriate technical equipment should be installed

for this purpose. Another important item is the measuring equipment for each

process step including calibration. Training staff to maintain an individual ob-

servations chart or CAQ system within the realms of operator self-inspection

is instrumental in the early recognition of process risks and intervention in the

machine control or initiating the dressing process if necessary.

Constant documentation of the susceptibility of wearing parts like drives, bear-

ings, bellows, electric sensors etc. is needed for preventative maintenance.

Early replacement of

these wearing parts dur-

ing quiet times will result

in effi cient manufacture

as much as multiple ma-

chine systems and run-

ning without break peri-

ods. Cleanliness and

tidiness, low stock levels,

short cycle times, elimin-

ating waste, constant im-

provements and reducing

set-up time complete the

picture.

and surface roughness and to extend

dressing intervals. The choice of cool-

ant and the supply jets which deliver

the coolant directly to the workpiece

can also signifi cantly affect the grin-

ding result. The question whether it

would be sensible to use oil or emul-

sion in the processes largely depends

on the number of grinding machines

available at the component manufac-

turer’s facility. Lastly, a long-term prof-

itability study will determine whether

a central or stand-alone solution and

whether oil or emulsion should be

used. Christian Bauer has decided on

a central supply of emulsion for all their

machines. This particular technology

has been technically perfected and

works with residual particle sizes of

fi ve to six microns. As a result, the com-

pany is able to handle all kinds of grin-

ding materials from high-speed steel,

100Cr6, sintered steel to other types of

hardened or unhardened steel, with

great success.

ABOUT THE SPEAKER

Dr August Kästner is Managing Director of Christian Bauer GmbH + Co. KG. The Welzheim-based company manufac-tures disc springs and precision parts for vane pumps and camshaft adjustment systems

and motors

Precision parts: Avoiding

fl ow losses in vane pumps

Coolant

Minimize time expenditure,share in the company’ssuccess, training

Work towards accurate manu-facture, dedica-ted measuring equipment

Reliable subcontractors

Minimize expenditure

Production/machines/

equipment/manufacture

Tools

Employees

Cost

of i

nspe

ctio

n/

Insp

ectio

n eq

uipm

ent

Material/unfi nished parts

Operational and

administrative costs

Customer

Product

Price

Introducing innovative concepts through contact with machine

manufacturers, tool manufacturers, research facilities

Well-rounded: Diverse criteria ensure the best products

L_Vortrag_II4_Ka stner_E.indd 45 09.04.2009 17:40:08 Uhr

46 MOTION 01/09


ciently rigid design it contributes to an improvement in roundness and cylindric-

ity and corrects any position errors. There is no need for a special feed attachment

as the machine axes transpose all tangential, radial and axial movements. The

design of the honing tool permits a split into two processing sides. Different

honing stone specifi cations can be used for a variety of processing steps, for

example, a honing stone with rough grain for rough machining on the fi rst process-

ing side and a fi ne grain stone for fi nishing on the second side.

With combined turning-grinding-honing machines it is possible to process ro-

tational symmetrical workpieces from blank to fi nished component on one ma-

chine and in a single clamping. Depending on the required component quality,

combined machining can consist of turning and grinding, turning, grinding and

fi nish-honing, or turning, pre-honing and fi nish-honing.

The combined turning, grinding and honing process improves the surface qual-

Nowadays, the combined turning

and grinding process is the pre-

ferred method for internal cylindrical

machining of hardened components.

It combines the advantages of turning

with those of grinding, i.e. a high

achievable stock removal rate and high

flexibility while maintaining high pre-

cision and surface quality. Over the

past years, the ISF has explored two

further concepts for internal cylindrical

machining: extending the existing

combined machining process by a hon-

ing process and internal cylindrical

peel grinding.

Honing reduces production time

The basic advantages of honing are

reliability, high accuracy and excellent

surface structures. Furthermore, hon-

ing can reduce edge damage caused

by pre-machining, or even rectify it. In

addition, the process induces residual

compressive stress into the surface of

the component which extends the life

of the functional surfaces. Expanding

an existing turning and grinding ma-

chine with a honing facility thus offers

the possibility to reduce production

times and to react fl exibly to quality

requirements.

The honing tool developed specifi cally

for the combined turning-grinding-

honing machine is impressive due to

its simple design without additional at-

tachments for feed or measuring. It is

integral to the machine and in a suffi -

High material removal rate: Process kinematics and contact conditions in internal cylindrical peel grinding

Lec ture I I I -1 | May 7, 20 09 | 14 .0 0

Turning, grinding, honingThe Dortmund Institute of Machining Technology (ISF) examined innovative concepts forcombined machining and internal cylindrical peel grinding.By Prof. Klaus Weinert

Workpiece

Workpiece

axial feed rateworkpiece circumferential speedtotal radial grinding allowanceeffective infeedaxial feed rateeffective contact width

angle of scrubbing zonewidth of smoothing zonespecifi c material removal rategrinding wheel speedworkpiece speedworkpiece diameter

Grinding wheel Grinding wheel

PROCESS KINEMATICS CONTACT CONDITIONS

L_Vortrag_III1_Weinert_E.indd 46 09.04.2009 17:42:20 Uhr

47MOTION 01/09

[1][1] [2][2]

by dividing the grinding wheel into different functions, i.e. a cone-shaped

scrubbing zone for stock removal and a cylindrical finishing zone for perfecting

surface quality.

Contrary to grinding, hard turning is characterized by high fl exibility and high

material removal rates. A comparison with hard turning proves the advantages

of internal cylindrical peel grinding with regard to accuracy and effi ciency. While

internal cylindrical peel grinding uses an electroplated CBN grinding wheel and

grinding oil, the hard turning process is carried out dry with a CBN insert. Chip

formation and the circumferential speed of the grinding wheel have a consider-

able infl uence on the axial force in the process. Axial force in internal cylindrical

peel grinding is ten times as small as in turning while the amount of stock re-

moved stays the same. The high feed rates in turning also lead to higher surface

roughness compared with internal cylindrical peel grinding.

Constant striving for increasing productivity and fl exibility strengthen effi ciency

and competition of a manufacturing business. Demand continues to move towards

smaller lot sizes and an in-

creasing selection of op-

tions while product life cy-

cles are constantly being

reduced. To this end, hard-

fi ne machining is taking on

some of these processing

tasks. Thanks to new con-

cepts like the one described,

the effi ciency of production

processes will continue to

be increased in the future.

ities of the components with each pro-

cess step. The fi nal honing process

creates the surface structure typical for

honing. With the alternative turning-

honing-honing process chain this struc-

ture has already been achieved after

the fi rst honing operation. The struc-

ture shows greater surface roughness

though, which is reduced by fi nish hon-

ing. Both process combinations have a

positive infl uence on the component

shape and the cylindricity error ob-

tained was less than 2 μm in both ca-

ses. However, the turning-honing-hon-

ing process combination did not achieve

the same surface qualities as the turn-

ing-grinding-honing process chain.

Internal cylindrical peel grinding

Internal cylindrical peel grinding also

produces high material removal rates

whilst maintaining excellent surface

quality. In this process a specially

shaped grinding wheel moves along

the borehole by axial infeed. The

amount of stock to be removed is only

set once. This has been made possible

ABOUT THE SPEAKER

Prof. Klaus Weinert has been head of the Institute of Machining Technology (ISF) at the Technical University in Dortmund since 1992 and he is also a member of the research association for manufacturing technologies

Combined machining: [1] Three operations on one machine [2] Rigid honing tool with two processing sides

1st processing side

Turning Honing Grinding

2nd processing side

TWO PROCESSING SIDES

L_Vortrag_III1_Weinert_E.indd 47 09.04.2009 17:42:20 Uhr

New grinding spindles for very high speeds reduce the use of lubricants and increase durability.

250.000 min-1 for small bores

To operate effi ciently, a machine tool spindle must have the appropriate load capacity, rigidity and dynamic run-out. In order to guar-

antee these characteristics even for extremely high speeds, the GMN development department was

faced with extraordinary challenges. Breaking points are reached due to high centrifugal forces, a compact design has to ensure subcritical op-eration with suffi cient distance to the fi rst critical speed, high-precision hybrid bearings have to be designed specifi cally for the demands of high-speed spindles. These challenges were met with the help of current advances in motor technology

and the use of further developed GMN spindle ball bearings. It is now possible to effi ciently grind small

internal geometries with up to 250,000 min-1. The GMN

P rocessing small internal diameters with optimum cutting speeds re-

quires high rotational speeds. New GMN spindle ball bearings with very high speed characteristics permit 250,000 revolutions per minute, for in-stance, with comparatively high spin-dle rigidity and load capacity. Opti-mized lubrication of high-speed spindles offers great potential for in-creasing performance. Furthermore, on-demand minimal lubrication lowers oil consumption and increases service life. In future, integrated data loggers will monitor the condition of the spin-dle, store the operating parameters and guarantee high availability. GMN has a long track record of supplying a wide range of high-frequency spindles with speeds of up to 180,000 min-1. How-ever, around two-thirds of the spindles supplied for internal grinding operate with maximum speeds in the 30,000 to 90,000 min-1 range.

Lec ture I I I -2 | May 7, 20 09 | 14 .45

Intelligent spindles


48 MOTION 01/09

A lot of knowledge in a small space: Intelligent electronics store sensor signals, process them and report any

exceeding of critical values to the overall machine control

To operate effi ciently, a machcapa

antesp

f

abea

interna

By Dr Bernd Möller

Temperature

– bearings

– coil

– coolant

Speed

Tool clamping system

Vibration

SPIDER• Record data• Monitor spindle• Monitor process• Transfer measured data

SERIAL INTERFACE• RS232• RS485• CAN• PROFIBUS

Intelligent spindle unit

Sensors for

Maximum speed: GMN high-frequency

spindles achieve speeds of up to

180,000 min-1

L_Vortrag_III2_Mo ller_E.indd 48 09.04.2009 17:49:28 Uhr

grinding spindles used for this purpose have a comparatively large and rigid mounting – the speed characteristic n·dm amounts to up to 4.5·106 mm/min – and a powerful synchronous motor. Consequently, they are suitable not only for special applications at maxi-mum speeds but can also be used fl ex-ibly and effi ciently in a relatively large rotational-speed range.

Integrated lubrication module

These days, ball bearings with perma-nent grease lubrication or oil/air lubri-cation are predominantly used in main machine tool spindles. Yet both meth-ods have their disadvantages which can be overcome by an innovative micro-dosing system combined with appropriate lubrication strategies. Compared with today’s oil/air lubrica-tion method, a signifi cant reduction of the lubricant quantity necessary is to be achieved and the systematic per-formance limits of grease lubrication, i.e. limited usable life of grease at high speeds and temperatures, are to be exceeded. Minimizing lubricant quanti-ties makes ecological and economic sense. It facilitates the integration of an oil reservoir into the spindle and

Important criteria for investment decisions: Control of lubricant quantity depending

on demand

Synchronous motor: Flexible use of grinding spindles in relatively high rotational

speed ranges

ideally requires no more external components. The problems associated with waste oil disposal are also defused. Operating costs of machine tools can exceed acquisition costs several times over if calculated over a normal life cycle. These costs are therefore a decisive factor for many users when making investment decisions. An integrated lubricant cartridge means that high-maintenance ex-ternal components can be dispensed with. The lubricant reservoir only needs replacing at relatively long intervals. An almost instant dosage of lubricant ensures that the adjustment of the lubricant quantity matches demand based on exact measurements of the bearing. This increases the reliability and effi -ciency of the bearing and reduces the quantity of lubricant needed.

Third generation spindles for machine tool

Spindles are also becoming more and more intelligent. Miniaturized electron-ics which are integrated in the spindle store the sensor signals, process them and report any exceeding of critical values to the overall machine control system. Important operating data can be accessed during the entire running time of the spindle and can be analyzed with regard to optimizing the process, machine and spindle. In addition, the aim is to go for bearing condition mon-itoring and consequently early damage detection, based on these intelligent systems. Evaluating temperature sensors, position sensors and vibra-tion sensors will increase precision and productivity of the production process. Additional sensors, on the other hand, harbor the risk of reduc-ing the availability of the spindle sys-tem further, therefore, as few addi-tional sensors as possible should be employed and for the time being, a more intelligent analysis of available signals should be aimed for.

49MOTION 01/09

ABOUT THE SPEAKER

Dr Bernd Möller is head of the Engi-neering Spindle Technology division at GMN Paul Müller Industrie GmbH & Co. KG in Nuremberg

Dosage element

Speed

Speed

Lubrication control

Bearing monitor

Process forces

Spindle drive

Spindle cooling system

Observer

Mot

or h

eat

Bea

ring

tem

pera

ture

Stator temperature

Coolant temperature

Machine control

Spindle bearing

Quantity of

lubricant

Lubricating

fi lm estimated

Power lossG9L(s)

Spee

d [1

min

]

Cutting speed [m/s]

0 5 10 15 20 25 30 35 40 45

300.000

250.000

200.000

150.000

100.000

50.000

0

Grinding wheel – Ø [mm]

L_Vortrag_III2_Mo ller_E.indd 49 09.04.2009 17:49:35 Uhr

50 MOTION 01/09


ties are expected to comply with. Hirschvogel Umformtechnik GmbH in Denklingen

is the master factory for forming and Hirschvogel Komponenten GmbH in Schon-

gau is the master factory for machining. New components are developed in co-

operative partnership with the customer to optimize costs. The customer provides

the knowledge of the product and Hirschvogel provides manufacturing expertise.

The two can thus work together to develop the ideal components.

The QM-online quality management system can be used to generate test batch-

es through the company’s own SAP system. All the test machines are connected

to the system. When required, it is possible to export assessments, perform

analyses and even, using the data matrix or clear text, assign the appropriate test

data to each individual component. As a rule, this is done for components that

have a high added value.

Increasing standard machine capacity

Machine planning is a particular challenge for an automotive supplier. The key data

for a new project and the capacity for series production must already be in place six

months before the start of production. Hirschvogel usually receives an order for 80

to 100 per cent of the customer’s requirement with a non-binding quantity estimate.

This can then vary by another ±15 per cent. These imponderables can only be con-

Every year some 200,000 tonnes of

massive formed components leave

the Hirschvogel Automotive Group’s

factories. The automotive supplier, from

Denklingen in Bavaria, Germany, has an

international presence, with sales of-

fi ces in the USA, China, Brazil and India.

Three thousand employees generate a

turnover of more than 500 million euros.

This makes Hirschvogel one of the lar-

gest suppliers in this sector. The com-

ponents are produced by forging, cold

forming, warm forming and combined

processes and weigh between 0.1 and

25 kilograms each. Hirschvogel has suc-

cessively broadened its production ex-

pertise to include machining with heat

treatment and now supplies components

ready to be installed directly on the cus-

tomers’ assembly lines.

The company’s core business is the

large series production of extremely

complex formed components. It sup-

plies the fi ve product groups, namely

transmission, chassis, drive train, injec-

tion and engine. Hirschvogel can offer

its customers throughout the world, who

include virtually all original equipment

manufacturers (OEM) plus fi rst and

second-tier suppliers, a uniform quality

standard and identical technologies.

‘Master factory functions’ specify the

standards that all the production facili-

Lec ture I I I -3 | May 7, 20 09 | 15 .30

One concept for every siteThe Hirschvogel Automo-tive Group uses a standard machine concept in all its production facilities through-out the world.By Harro Wörner

A bundle of power: Many vehicles on

the road have components formed by

Hirschvogel Automotive Group

L_Vortrag_III3_Wo rner_E.indd 50 09.04.2009 17:50:44 Uhr

51MOTION 01/09

[1][1] [2][2] [3][3]

[4][4]

[5][5]

Grinding and measuring

For grinding, Hirschvogel uses ma-

chines from a variety of manufacturers

in its internal module. The process that

is needed in each case, for example

centerless cylindrical or non-round

grinding or a combination process, de-

termines the machine that is chosen

for it. Even though the grinding ma-

chines are supplied with the appropri-

ate technology for in-process measure-

ment or for measuring component

alignment, Hirschvogel uses addition-

al forms of analysis and test methods

to determine depth of roughness, twist

and the properties of peripheral areas

in the workpiece, and also uses vibra-

tion analysis. The latter has proven

worthwhile, particularly in the grinding

of roller bearing seats.

Hirschvogel requires the future gen-

eration of grinding machines to offer

a considerably higher

potential for cost reduc-

tion. The machines have

to be able to offer much

greater versatility of use

and the ratio of basic

machines to type-spe-

cifi c investment must be

better, as the batch sizes

and service life of the

products are also in-

creasingly subject to

change.

trolled by having a scalable production

system on the modular principle. Hirsch-

vogel has opted for a standard machine

concept that can produce goods at com-

petitive prices with appropriate automa-

tion. The decision regarding the best

technology for the job is taken during the

course of the project. The machine is cho-

sen and equipped from standard mod-

ules. This enables Hirschvogel to produce

samples by hand that are close to their

series production counterparts. The re-

quired capacity must be installed before

production begins. It is only by this means

that the desired Run@Rate and process

acceptance can be confi gured with the

customer. Capacity is increased by com-

missioning duplicate machines and using

the corresponding automation.

Automation concept

The automation concept is developed

from the value stream planning in each

case. Hirschvogel usually uses stacking

cells or circulating conveyors. The reason

for this is that although direct linking is

usually best for a value stream, it is not

necessarily the most cost-effective solu-

tion in respect of capacity, as the quan-

titative data provided by the customer is

not binding and can vary between zero

and a hundred per cent. Only the cost

calculation at the end of the project

shows whether the automation concept

was actually able to optimize the costs.

ABOUT THE SPEAKER

Harro Wörner Harro Wörner is CEO of Hirschvogel Kompo-nenten GmbH in Schongau. Since 2002, he has been responsible for the global production network for the machining of formed compo-nents within the Hirschvogel Automotive Group

Hirschvogel supplies components for five different groups of products: [1] Chassis [2] Drive train [3] Transmis-

sion [4] Engine [5] Diesel/Gasoline injection

L_Vortrag_III3_Wo rner_E.indd 51 09.04.2009 17:50:45 Uhr

52 MOTION 01/09


Synthetic resin bonding materials are soft grinding universal binders with

phenolic resin and polyimide resin binding agents

Galvanic bonds hold the abrasive in a single-layer coat, the thickness

of which is roughly that of the average grain size used. Tools with this

type of bond cannot be dressed

Metallic sintered bonds are highly wear-resistant

On all grinding tools, the abrasive

material used and how it is bond-

ed are of prime importance. Composi-

tions vary depending on the applica-

tion. Conventional abrasives such as

aluminum oxide (Al2O3) or silicon car-

bide (SiC) are bonded in ceramic or

synthetic resin materials. Super-abra-

sive materials such as CBN or diamond

are additionally secured in metal bond-

ing materials. The type of bonding ma-

terial used and its internal structure

largely determine the grinding and

dressing behavior.

Ceramic bonded CBN grinding

wheels are mainly used in series

and high-volume production. Their

high metal removal rates and

surface characteristics mean that

they are well suited to high-speed

grinding. Dressing is simple

Lec ture I I I - 4 | May 7, 20 09 | 16 .15

Great potential savings

Diagonal grinding with super-abrasive CBN wheels is not dependent on geometry. The process reduces grinding time by up to 80 per cent.

Al2O

3: Abrasives such as

aluminum oxide infl uence

grinding and dressing behavior

TRENDS IN GRINDING TECHNOLOGY

By Udo Mertens

MARKET DEMANDS IN E.G. THE AUTOMOTIVE SECTOR

Lower noise emissions

Lower CO2-emissions

More powerful engines

Lower consumption

Greater reliability

Longer service intervals

Lower purchase prices

L_Vortrag_III4_Mertens_E.indd 52 15.04.2009 14:03:25 Uhr

53MOTION 01/09

to be machined in a single operation. Two grinding processes run simultane-

ously with differing process kinematics. The advantages are:

A shorter grinding feed traverse saves time

Shorter contact length at the fl at shoulder minimizes the

risk of thermal damage

Reduced loads on the edge of the abrasive coating

Even so, there are disadvantages associated with the angular position and the

geometry of the workpiece. A large area of abrasive coating is needed for grinding

the fl at shoulder. Since it does not make economic sense to reprofi le super-abra-

sive grinding wheels, a change of workpiece to one with a different profi le means

that the CBN tool has to be changed as well. This involves a longer idle time. In

addition, CBN grinding wheels with wildly differing geometries have to be kept in

stock – an additional cost factor. This is where diagonal grinding offers great sav-

ings potential. The axis of the workpiece is parallel to that of the grinding spindle.

The angular infeed is achieved by simultaneous movement in the radial and axial

directions. Thus the same tool can be used to grind virtually all geometries on the

circumference and the fl at

shoulder without the need

to change the geometry of

the coating. This is par-

ticularly advantageous for

short runs. Studies by

Saint-Gobain have shown

that the processing time

with diagonal grinding can

be up to 80 per cent short-

er than that required for

straight infeed grinding.

Conventional grinding tools are made

entirely of abrasive material. CBN and

diamond grinding wheels, on the other

hand, have a relatively thin coating of

abrasive that is bonded to a carrier ma-

terial. The choice of this material de-

pends on, among other things, the

grinding job and the conditions of use.

In addition to good thermal conductiv-

ity and vibration damping it must pos-

sess suffi cient mechanical strength.

The following materials are available:

Aluminum

Steel

Synthetic resin, with or

without metal fi llers

Ceramic

Composites

Examples: Camshaft bearings

To date the use of galvanically bonded

CBN grinding wheels for plunge-cut

rough grinding of the bearing points on

a GGG camshaft in a centerless grin-

ding machine has required a support

bushing, seven grinding wheels and

four spacer rings. It is not economi-

cally feasible to dress the single layer

coating of these grinding wheels with-

in a few micrometers. Saint-Gobain

Diamantwerkzeuge GmbH & Co. KG has

therefore developed a grinding tool

with a single carrier material which is

far more durable. All the areas of the

abrasive coating are machined without

re-clamping and there is no need to

dress the profi les. These are more eco-

nomical because they have a longer

tool life and they cost considerably less

to manufacture.

Examples: Crankshaft ends

In practice, shaft ends are machined by

external cylindrical angular infeed

grinding or infeed grinding with a

straight cut. In external cylindrical an-

gular infeed grinding the grinding spin-

dle and workpiece axis are set at a de-

fi ned angle with respect to each other.

The angular position enables high fl at

shoulders and circumferential surfaces

Advantage of angular infeed grinding: Circumference and fl at shoulder are machined simultaneously

ABOUT THE SPEAKER

Udo Mertens is responsible for product management and product development for ceramic bonded CBN and diamond tools at Saint-Gobain Diamantwerkzeuge GmbH & Co. KG

Straight infeed grinding

Angular infeed grinding

GRINDING SHAFT ENDS

L_Vortrag_III4_Mertens_E.indd 53 15.04.2009 14:03:33 Uhr

54 MOTION 01/09


Economic rise and fall

There always have been economic downturns, and there always will be. If a

company depends on a single business sector for its customers, it’s also going

to experience the ups and downs of this sector itself. This is why it is essential

for tool grinding companies to address a wider audience and serve different

sectors. Generally, tool grinding companies have two decisive advantages:

The machine tool mechanic is trained both for the

initial manufacture and for subsequent sharpening

of cutting and machining tools

CNC tool grinding machines are used for sharpening as

well as for the manufacture of various tools in different numbers

In this way, a range of different orders can be secured, accepted and processed

and the growing market for special tools can be serviced. Most of the major tool

manufacturers are not suitably equipped for manufacturing these special tools in

penny numbers. This gives the tool grinding operators a major advantage. Never-

When resharpening a metalwork-

ing tool, the toolmaker has to

decide anew every time whether the

costs of sharpening will exceed the

costs of replacement by a correspond-

ing new tool. Take classic twist drills,

for example, these days, companies

set their own diameter limits below

which sharpening is no longer eco-

nomical. These limits also depend on

the level of automation of the grinding

centers. No matter what the kinematics

are behind the CNC tool grinding ma-

chine: with fi ve CNC axes, almost all

rotationally symmetrical machining

tools can be ground. Here, apart from

the machine’s automatic handling

system, the fl exibility of the clamping

system has a major infl uence on the

economy of the grinding machine’s

operation.

The variety of parts stocked by tool

grinding companies is extensive. One

customer order includes a number of

different drill-bits or mixed types of

tools, on another occasion it includes

a large number of identical special

tools. Given this extreme variation in

orders, quick decisions and skill are

demanded of the cutting tool maker. In

addition there is the maintenance of

short delivery schedules of a week to

a maximum of a fortnight to be consid-

ered – one of the strengths of these

companies. But this is exactly where

the danger lies: with no orders coming

in, the turnover drops immediately.

Advantageous: An order is completed as a rule within a week, but in any case in a maximum of 14 days

Lec ture IV-1 | May 8 , 20 09 | 9 .30

The cutting edge industry: tool grindingIn tool grinding, quick decisions and skill are demanded of cutting tool makers, so that short delivery schedules can be maintained.By Prof. Wilfried Saxler

Receipt of order Delivery date Sales

3–10 working days

ONE STRENGTH OF THE TOOL GRINDING COMPANY IS THE SHORT DELIVERY TIME

Time

L_Vortrag_IV1_Saxler_E.indd 54 09.04.2009 17:54:11 Uhr

55MOTION 01/09

also improves fl exibility and enables crisis situations to be overcome more

easily. Grinding shops are an ideal size for this. They are generally small com-

panies with an average of fi ve employees. A good quarter of them have between

six and fi fteen staff. If a company has a large number of customers, naturally

expenditure on sales and distribution work, logistics and therefore also for ac-

counting rises. But the risk that turnover is suddenly going to plunge is consid-

erably less. Well prepared, the

companies which have provided

for conditions like those men-

tioned above will be able to handle

the diffi cult economic situation.

And any company which has so

far not faced this subject now has

the opportunity to do so. Make

your company fi t for the next eco-

nomic boom – now. Because it’s

on its way...!

theless, the conditions for manufactur-

ing and sharpening a tool are very dif-

ferent (see table).

React fl exibly

The conditions and fi elds of activity

outlined above thus presuppose fl ex-

ibility in every respect. A business can

only be regarded as fl exible if

it can handle differing technical

enquiries on types of tools

it is quick to react to customer

enquiries

in addition to sharpening tools, it

manufactures special tools

it can adjust its tool grinding

machines quickly to perform new

tasks

is a master of grinding technology

it can handle large production runs,

and in particular small runs

For this it will require a large range of

parts, short processing and delivery

times, improved staff productivity,

shorter idle times and a suitably adjust-

able level of automation.

All these criteria can only be achieved

with highly-qualifi ed personnel. Coop-

eration with other grinding companies

Well prepared: Tool grinders are mainly small

companies with between two and five employees

Reassuring: If a company has plenty of customers,

there is less risk that business will suddenly collapse

THE CONDITIONS FOR MANUFACTURING AND SHARPENING TOOLS

Sharpening Manufacturing

Stock material Worn tool (from the customer) Blank (purchased)

Tool drawings Generally not present or required Not available Must be derived and created from the workpiece drawing

Preparations Visual check, cleaning if necessary Shaft preparation Determine amount of wear for grinding stock Dimensioning on measuring machine

Possible edge fracture at the end of the shaft

Clamping accuracy (circular runout)

Dependent on previous history (cannot be infl uenced)

Dependent on blank (can be infl uenced)

Programming expenditure Dependent on geometry Dependent on geometry Control possibility using simulation

Defi ning the position of the tool in the grinding machine

Complicated tool probing operations necessary for helix angel, rotation position, unclamped length, long tooth detection etc. Only detection of the unclamped length necessary Resetting the open-face or cutting face without infl uencing the tool function

Specifi cations according to drawing

Grinding from the solid block

ABOUT THE SPEAKER

Prof. Wilfried Saxler is Managing Director of the Fachverband Deutscher Präzisions-Werkzeug-schleifer (German Precision Tool-grinders Trade Association)

6 to 15 staff27%

over 15 staff 5%

1-man-opera-tions7%

Sales /business risk

Logistic /accountancy expenditure and ancillary costs

2 to 5 staff 61%

SIZE CLASSIFICATIONS OF GERMAN TOOL

GRINDING COMPANIES

AN INCREASE IN CUSTOMER NUMBERS OFFERS

BETTER SECURITY IN TIMES OF ECONOMIC

FLUCTUATIONS

Number of customers

L_Vortrag_IV1_Saxler_E.indd 55 09.04.2009 17:54:12 Uhr

56 MOTION 01/09


Lec ture IV-2 | May 8 , 20 09 | 10 .15

Many axes ensure success

which in turn results in effi cient manufacture of high accuracies whilst maintain-

ing complex geometries.

Innovative high-performance drills

Among the machining processes drilling is an important one because of its 40-per-

cent share of production time. In addition, solid drilling when processing pilot holes

as a fi rst process step is a determining factor in the achievable fi nal quality. Con-

sequently, innovative high-performance drills like the MAPAL MEGA Quadro-Drill

or the MEGA-Deep-Drill have to guarantee high cutting values and have to provide

excellent results for roundness, straightness and diameter tolerance. That is why

MAPAL is using modern multi-axis grinding machines with the appropriate software

in its production processes. Only these machines are capable of processing the

specifi c geometries which are

responsible for chip formation

and cutting behavior of the drill

in a single clamping.

Apart from the margins which

are situated directly behind the

cutting edges, the MEGA Quad-

ro-Drill and the MEGA Deep

Drill have two additional guid-

ing margins which have con-

stant contact with the wall of the

hole created while drilling. As a

result, roundness and straight-

ness of the hole produced are

considerably improved. The

specifi c geometry also opti-

mizes self-centering and brings

advantages when exiting drill

holes at an angle. Due to the ad-

ditional support, the drill oper-

ates very quietly even with in-

creased cutting rates for steel

and cast materials. The deep-

New, specially developed tools are

often an important infl uence on the

success of a product because high-

performance tools help to transform

machine effi ciency into high-quality

products. Grinding in particular plays a

central role in the effi cient manufacture

of innovative tools. Highest precision

– reliable and guaranteed to be repro-

ducible – is virtually a basic require-

ment. The multi-axis design of the

grinding machine furthermore ensures

the complete machining of high-per-

formance tools in a single clamping,

MAPAL high-performance drilling tools

Without multi-axis precision grinding machines there would be no modern high-performance tools. MAPAL Dr. Kress KG is relying on this technological advantage.By Dr Dieter Kress

4 cutting edges for twice the feed rate

4 margins for better drilling quality

Drilling and reaming – one operation

Deep hole drilling up to 30×D

MAPAL GIGA-Drill

MAPAL MEGA Quadro-Drill

MAPAL MEGA Drill-Reamer

MAPAL MEGA Deep-Drill

L_Vortrag_IV2_Kress_E.indd 56 09.04.2009 17:59:26 Uhr

57MOTION 01/09

quire around 20 per cent less torque than conventional twist drills with feed rates

remaining the same. This means that the cutting speeds for cutting steel with up

to 200 m/min can be doubled with tool life travel remaining the same.

Modern reamers

Modern multi-fl ute reamers signifi cantly reduce processing times for precision

drilling through high cutting speeds and very high feed rates. MAPAL sets new

standards in this area with its high-performance reamers. In order to guarantee

utmost precision in the μm range on all levels of the high-performance reamers,

the complete cutting geometry including all angles of the entire tool has to be

fi nished in one clamping following the cylindrical grinding process. Only multi-

axis grinders with measuring systems and in-process dressing facilities can solve

this task effi ciently. The same applies to PcBN reamers or cutters employed in

machining cast materials or in hard machining. When grinding PcBN, oscillating

axes as well as compensation of wheel wear should be preset, in order to avoid

clogging and scoring of the grinding wheels.

The new MAPAL reamers are equipped with PcBN cutting edges even in the di-

ameter ranges of less than 6 millimeters. In this instance, PcBN is applied to the

front face and reproduc-

es the entire cutting ge-

ometry, resulting in big

advantages of tool life

compared with conven-

tional carbide reamers.

When hard machining a

hole with Ø 2.4 H7,

MAPAL managed to in-

crease the output of a

carbide reamer from

around 50 holes to over

1,300 holes with the

PcBN reamer.

hole drill has specifi c fl ute geometries

and fl ute angles which provide good chip

clearance. Chips roll up tightly without

jamming and are removed safely even

from great drilling depths thanks to high-

ly polished surfaces.

The MAPAL MEGA drill-reamer com-

bines drilling and reaming in a single

operation. The process combines dou-

ble-edged drill geometry with up to six

reaming margins for fi nish machining

the bore. The reaming margins protrude

radially by a few hundredths of a mil-

limeter above the drilling margins, re-

sulting in a defi ned reaming allowance.

In contrast, the drilling margins are in

front of the reaming margins along the

axis. Universally designed for use with

steel, cast iron and aluminum, the MEGA

drill-reamer has an excellent self-center-

ing ability and is an extremely effi cient

tool for pinhole drilling.

The latest development in MAPAL’s

solid carbide range is the MEGA Speed

drill. With its innovative face geometry,

it guarantees safe chip control, reduced

feed force and excellent self-centering

ability. As the guidance lands are no

longer arranged on opposite sides, the

drill can no longer get jammed in the

hole. Measurements show that due to

reduced friction MEGA Speed-Drills re-

ABOUT THE SPEAKER

Dr Dieter Kress is managing director of MAPAL Dr. Kress KG. The company specializes in precision tools for metal working; it is the headquar-ters of the MAPAL group which employs more than 3,000 staff in 20 different countries

View of the MAPAL production facility: Multi-axis grinding technology for high-performance tools Utmost precision: MAPAL high-performance drilling tools

L_Vortrag_IV2_Kress_E.indd 57 09.04.2009 17:59:26 Uhr

58 MOTION 01/09

Lec ture IV-3 | May 8 , 20 09 | 11.0 0

More power for microchip removal


The Institute for Machine Tools and Factory Management (IWF) at the TU Berlin exam-ined characteristic phenomena of microchip removal with the aim of developing new potentials for micro end milling cutters.By Christoph Hübert

milling tool ‘ploughs’ across the workpiece and reduces its surface quality. At

the Institute of Machine Tools and Factory Management (IWF) at the Technical

University Berlin, these characteristic phenomena have produced several ap-

proaches for developing new potentials for micro chip removal.

Tool geometry

Macro-range tools cannot be scaled down randomly into the micro range (tool

diameter < three millimeters). Geometric scaling produces unfavorable chip

formation mechanisms, resulting in an increase in process forces which in turn

leads to premature tool wear. A wide range of tools from earlier micro end mill-

ing cutters are not involved in chip formation. Furthermore, these tools show

a noticeable discrepancy between the effective tool length which has been

prepared with cutting edges and the axial depth of cut.

New approaches in tool construction were able to eliminate these weak points.

In micro milling, cutting edge round-

ing is of similar size to the chip thick-

ness. Therefore, variations of cutting

edge rounding due to geometric de-

viation of the tool or the coating affect

the process results more than in mac-

roscopic chip removal.

Micro milling tools are fl exible due to

their small shank diameter. They warp

elastically during the process resulting

in erratic variations in chip thickness

which can lead to premature tool fail-

ure if exposed to extreme stress. If the

minimum chip thickness is undercut,

neither shear plane formation nor chip

removal takes place; instead, plastic

strain of the workpiece occurs. The

Not involved in chip formation: Subdivision of the cutting area of traditional peripheral face milling cutters

Area of most common tool failure

Area where mainly frictional force is effective

Zone where the stock removal process takes place

Tool 6-Iz = 3ap = 0,1 mm

500 μm

L_Vortrag_IV3_Hu bert_E.indd 58 09.04.2009 18:00:59 Uhr

59MOTION 01/09

Reference structures with varying machining results: Hardened powder metallurgy steel (1.2379, 54 HRC)

and brass (CuZn39Pb3) have proved to be a suitable sample material. Fluted microstructures for deep

milling and simple surfaces for the fi nishing process are used as reference structures

at their disposal as well as the

HELICHECK PLUS measuring sys-

tem developed by WALTER which

includes high-resolution cutting

edge measuring sensors. The

measurement of process force is

an established and significant pa-

rameter in the characterization of

process behavior for procedures

involving the geometrically unde-

fined cutting edge. The IWF uti-

lizes the evaluation of internal

drive signals of linear direct drives

of the main thrust axes in order to

maintain a database for the ef-

fects of varying process param-

eters and grinding tool specifica-

tions for typical tool grinding

operations, in spite of existing

limitations of data collection.

Apart from the geometric charac-

teristics, the process parameters

of the grinding operation infl uence

the rigidity of the micro tools and

also, indirectly, the process reliab-

ility of the chip removal process.

The IWF investigated the quantifi -

cation of this relationship. First,

the effect of cylindrical grinding of

carbide on the rigidity was analyzed. With micro tools, the machining of the

diameter takes up most of the chip volume and the machining time at the cutting

edge and the transaction piece. Secondly, the effect of the cutting edge on the

rigidity of solid carbide tools was studied. The grinding operation determines

the edge-holding property and the rigidity of the tool through shape and qual-

ity of the cutting edge and the underlying edge.

Use of micro cutting tools

Currently, the IWF is studying the high-precision milling process in terms of

its effects on the structure of machine tools. Apart from a better understand-

ing of the process/machine tool behavior, the objectives are the development

and application of a forecast model for predicting these interactions and to

establish a basis for:

manufacturing microstructures

while observing tight

tolerances and high surface

requirements and

guidelines for design and

confi guration of the

machine tool structure in

terms of optimization of

design and topology

Parameterization of the tool geometry,

for example, enables automatic gen-

eration of different geometry charac-

teristics and the use of the finite ele-

ments method for optimizing tools

according to demand. This makes the

manufacture of milling tools with vary-

ing diameters and geometric charac-

teristics much simpler as the geomet-

ric data can be entered directly into

the machine tool used for manufac-

ture. Workpiece-dependent optimiza-

tion can now be carried out quickly

and simply by varying the geometric

characteristics.

Manufacture

The manufacture of solid carbide

shank tools with diameters < three mil-

limeters requires state-of-the-art ma-

chine technology for both tool grin-

ding and tool measuring. The IWF has

a Schütte 5-axis tool grinding center

ABOUT THE SPEAKER

Christoph Hübert is chief engineer at the Institute for Machine Tools and Factory Management at the Technical University Berlin

Detail: fl ute base

Overall view

Detail: fl ute base

Overall view

Detail: fl ute base

Overall view

L_Vortrag_IV3_Hu bert_E.indd 59 09.04.2009 18:00:59 Uhr

60 MOTION 01/09

Lec ture IV- 4 | May 8 , 20 09 | 11.45

Metrology ensures profi tability


Tight tolerances and improved accuracy in tool manufacture: Fully automated precisionmetrology for the setting and monitoring of grinding machines and processes that is located close to production improves precision and productivity.By Oliver Wenke

ticularly for sensitive materials or very small dimensions. High-specifi cation measu-

ring devices, such as the HELICHECK series of measuring machines from WALTER,

work quickly, are non-destructive and have uniformly high reproducibility with no

operator intervention. All the relevant tool parameters can be measured. Optical

measurement permits the extremely rapid, almost simultaneous, recording of a

very large number of measuring points. Special measuring and evaluation pro-

cesses even allow measurements to be recorded over 360 degrees. They thus

record the actual shell profi le of the workpiece and transmit the measurements to

the process control, which makes appropriate corrections to the subsequent ma-

chining process where necessary. This reduces scrap and minimizes the time spent

on traditional fi nal inspection. Optical measurement is supported by powerful im-

age processing and an easily operated measurement control system. Special edge

detection processes, together with optimized illumination and image enhancement

software (see Figure 1, right) mean that even high-gloss polished surfaces, coat-

ings or matt surfaces can be measured without diffi culty.

The ‘Closed Loop’ solution

Absolute dimensional accuracy is critical for the performance of a shaping tool

and the result that it produces (see image left). The very tight workpiece tolerance,

sometimes less than +/- 3 μm, requires production and inspection processes to be

precisely matched. In the case of the HELICHECK, the measurement

program is based on the grinding program and can be pre-

pared offl ine in advance. This saves the need for time-

consuming programming. Automatic correction is done

by DXF comparison of the theoretical and actual con-

tours. The corrections are calculated automatically

and adopted by the grinding machine. This results in

‘good’ tools within the required tolerance and a stable

production process. Given a suitable automation solution

such as a loading robot, this can be a completely unattended process. In this

way, tight tolerances can be reliably and cost-effectively kept under control. With

an optical solution, a virtually unlimited variety of objects can be measured. Even

These days, reducing costs and in-

creasing productivity is part of the

daily grind of manufacturing. To stay

competitive, tool production processes

must continually overcome new chal-

lenges where quality, versatility and

costs are concerned. Increased costs can

only rarely be passed on to the custom-

er in the form of higher prices. Costs can

only be reduced by continually optimiz-

ing production and increasing productiv-

ity. For innovative toolmakers and

regrinders, this means very greatly

shortened cycles for new products or

services. This process can be success-

fully mastered with smooth coordination

of the experience of skilled tool develop-

ers with the most up-to date manufactur-

ing technology and suitable metrology.

Contactless optical measuring tech-

niques play an important part here, par-

Absolute dimensional accuracy: Crucial for the

performance of a shaping tool and its results

L_Vortrag_IV4_Wenke_E.indd 60 09.04.2009 18:02:39 Uhr

61MOTION 01/09

[1][1]

[2][2] [3][3]

cess. The size of the radii and the resulting sensitivity of the cutting edge require

special measuring procedures. The development of the cutting edge rounding

sensor (see Figure 3 above) opens up the possibility of accurately measuring μm-

fi ne face and contour cutting edge roundness on metal removing tools. This new

option can be used to determine the entire microgeometry of a cutting edge and

all the other profi les on microcomponents. The combination of a number of cam-

eras simplifi es orientation on the tool and thus contributes to accurate, compre-

hensible and reproducible determination of the measuring point. This is also pos-

sible even if the tool has been unclamped in the meantime. There is no need for

time-consuming manual pre-positioning. The measuring process lasts less than a

minute, with the actual measuring time being a mere 15 to 20 seconds. The rest of

the time is needed for the sensor to approach the component being measured. The

relationship with the other sensors ensures that measurements are absolute. In

addition to the radius, width and form of the cutting edge the system also deter-

mines its exact position on the tool.

Summary

The WALTER HELICHECK is a com-

plete system for all measuring tasks.

Tool grinders benefi t from cost-

effi ciently monitored production

and can therefore react quickly and

reliably to their customers’ wishes.

For both one-person businesses

and large companies, the potential

savings are enormous and continue

to rise as the variety of tools in-

creases.

shafts and diamond dressing rolls can

be measured without the need for ad-

ditional setting-up time. The optional

lighting table extends the potential ap-

plications to the measurement of non-

rotationally symmetrical forms such as

profi le sheets or indexable inserts. With

standard tools too, the measure-grind-

measure control circuit has a benefi cial

effect on tool optimization. It contributes

to improvements in cutting behavior,

tool performance and tool life.

Faster and more economical

If the geometry of the cutting edges is

optimized, the effect on machining char-

acteristics is highly benefi cial. Excellent

edge stability, fewer fractures and long-

er tool life make for improved machining

quality and quiet running at high metal

removal rates. The trend is towards

lesser rounding of edges and some

asymmetrical radii. Another reason why

the cutting edge radius was previously

generated in a rather random way was

because it was diffi cult to measure the

result precisely and draw conclusions

that could be incorporated into the pro-

ABOUT THE SPEAKER

Oliver Wenke is Headof the Measuring Technology Develop-ment Center at Walter Maschinenbau GmbH in Garbsen near Hanover, Germany

Advances: [1] Before-and-after results of the HELICHECK image enhancement system [2] Using optimally measured wheel sets on the HELICHECK, the fi rst tool is

usually already within the standard tolerance [3] The cutting edge rounding sensor enables accurate measurement of surface and contour cutting edge roundness

on metal-removing tools with μm precision

L_Vortrag_IV4_Wenke_E.indd 61 09.04.2009 18:02:39 Uhr

62 MOTION 01/09


Lec ture V-1 | May 8 , 20 09 | 14 .0 0

Process optimization using simulation

tolerance. The microgeometry is defi ned by the geometry of the grains and their

arrangement. In the case of engineered grinding tools, where it is assumed that

the grains are in defi ned positions, their actual locations are defi ned by the un-

certainty of the positioning process. The coolant and the chips occupy the clear

spaces between the grains. The stochastic tool model is fully defi ned in three

The use of empirical methods with

high-performance cutting tools is

not just time-consuming and expen-

sive, it is complicated by the fact that

many infl uencing factors come into

play simultaneously, making it very

diffi cult to assign the observed effects

and derive rules for them. In contrast,

analytical and digital tools and process

models can provide scientifi cally based

fi ndings.

Modeling

The simulation model for single-layer

abrasive coatings of diamond or CBN

grains consists of a stochastic model

of the tool, a kinematic model of the

process, a material removal model and

a failure and wear model. It enables the

number of active grains, their cutting

surfaces, and the resulting forces, ru-

gosity and service life to be defi ned

and the probability of their survival

under given conditions of use to be

evaluated. It is based on a simplifi ed

description of elementary events, ob-

tained from tests on individual grains

and simplifi ed for the purposes of nu-

merical treatment.

Stochastic model

The modeling for the tool incorporates

its macrogeometric and microgeomet-

ric properties. The macrogeometry is

described using the nominal geometry

of the grinding tool and the associated

Abrasive tool materials: Simulation models at the Swiss Federal Institute of Technology (ETH) in Zurich enable the number of active grains, their cutting surfaces, and the resulting forces, rugosity and service life to be defi ned.

KINEMATIC MODEL

Grinding speed Tool advance speed Workpiece speed

MATERIAL REMOVAL MODEL

Tool-workpiece interaction Rigidities Plasticity

MODEL OF COOLING

SYSTEM

Pressure, quantity Coolant

MODEL OF INDIVIDUAL GRAIN

Kienzle model Clamping forces Hardness

THERMAL MODEL

Temperature rise Thermal conduction

WEAR MODEL

Blunting of grains Grain fracture Jagged grains Clogging of interstices

Cutting data

Coolant fl ow Forces on the grains

Tool geometry

Tool/workpiece temperature

Change in tool

topologyWear

Failure

Proportion of active grains

Workpiece rugosity, chip space

Cutting area of grains

STOCHASTIC TOOL MODEL

Grain morphology Grain pattern Pattern accuracy Size and orientation of grains

Scientifi cally based: A view of the simulation model

By Prof. Konrad Wegener

L_Vortrag_V1_Wegener_E.indd 62 15.04.2009 14:06:42 Uhr

63MOTION 01/09

er hand there must be suffi cient clear space for the

chip that is removed to collect temporarily in the tool.

If overload occurs a greater or lesser proportion of

the grain can break off, or even be completely torn

out of the bonding material. This is taken into account

in the model by load thresholds for the various types

of change in grain geometry. Allowance can thus be

made for macroscopic effects such as clogging, scor-

ing and blunting of the grinding tool.

Behavior of individual grains

In practical cutting with individual grains it is possible

to determine the specifi c cutting force according to

Kienzle from the correlation of the measured process

forces and the scoring that is formed in the workpiece.

The orientation of the grain with respect to the direction

of cut must be noted. The load threshold at which the

grain fractures can be found by increasing the depth of

penetration into the workpiece.

Practical grinding tests have shown that an increase

in the specifi c metal removal rate has an effect on the

rugosity of the workpiece. This is because a higher

load on the active individual grains changes the sur-

face topology of the grinding wheel, depending on

the grain fracture behavior, and therefore changes

the distribution of active grains. Appropriate consideration of grain wear there-

fore has a critical infl uence on the quality of the rugosity that is calculated in

the simulation. At high cutting volumes in particular, the difference between

the numerical simulation and the measurement is greater when there is no wear

criterion. In the simulation model used, the active cutting surface of the grain

is used as the wear criterion. The critical cutting area at which the grain profi le

changes is correct when the measured number of fractured grains on the tool

and the workpiece rugosity are the same as the calculated values.

The change in grinding wheel topology can also be seen in the distribution of

the cutting surfaces of the grains. On tools that have not been ground there are

a few grains that have a large cutting area and these have a considerable infl u-

ence on rugosity.

Summary

The model enables

process and tool data

to be harmonized.

The interaction of

different simple models

and parameter studies

improves our under-

standing of the process

The effects of separate

parameters on complex

processes can be

unambiguously

investigated

cylindrical coordinates by the following

parameters, arranged in order of prob-

ability: grain size, grain shape, grain

orientation and positional deviations.

Material removal

The material removal model reduces

the complex elastoplastic processes

on the grain to the geometric interac-

tion of the abrasive grains with the

workpiece. This enables the new work-

piece surface that is created and its

rugosity to be determined in the mate-

rial removal simulation. Using Kien-

zle’s cutting force model we obtain the

force acting on each individual grain

and, by summation of this for all the

active grains, the process force acting

on the workpiece.

Failure and wear

When designing or selecting a grinding

tool the cutting and movement kine-

matics of the machining process must

be taken into account. On the one hand,

the individual grains must not be me-

chanically overloaded, but on the oth-

ABOUT THE SPEAKER

Prof. Konrad Wegener is CEO of the Swiss company Inspire AG für mechatronische Produk-tionssysteme und Fertigungstechnik and also Head of the Institute of Machine Tools and Manufacturing at the Swiss Federal Institute of Technology in Zurich

Idealized geometry: Grain morphology of diamond and CBN

THEORETICAL CRYSTAL MORPHOLOGY OF

SYNTHETIC DIAMOND

THEORETICAL CRYSTAL MORPHOLOGY OF CBN

Cube/octahedron

Octahedron/tetrahedron

Simulated grain morphology

Simulated grain morphology

Diamond PDA989

CBN ABN800

L_Vortrag_V1_Wegener_E.indd 63 15.04.2009 14:06:42 Uhr

64 MOTION 01/09

Lec ture V-2 | May 8 , 20 09 | 14 .45

Economic hard fi nishing


Shorter product cycles, niche products and site relocations require a high degree of standardiza-tion in plant procurement and plant reusability. This needs to be taken into account in the hard fi nishing of precision components.By Dr Frank Fiebelkorn

quired, for example contour editors designed for the workshop, interfaces for

importing contour data, simulations or the store of in-house knowledge and

skills. In addition to all this, the overall control system guarantees the integration

Optimization of future fi nishing

processes requires an overall view

of the appropriate machine concepts

plus the ability to use advanced manu-

facturing technology. To achieve the

ideal synthesis of high productivity and

versatility, two strategies stand out:

complete machining and combined

processing.

Using a modular machine structure it

is possible to pursue a consistent pol-

icy of complete machining. Often, it is

only by clamping the workpiece once

and for all that the required quality pa-

rameters in respect of surface fi nish

and accuracy of form and position can

be guaranteed. It is the only way to re-

duce throughput times. The machine

systems used in this way bring the func-

tions of a number of special machines

together on just one platform. The most

up-to-date programming and control

modules also contribute to the ability

to machine even non-round profi les or

threads completely without re-clamp-

ing the workpiece (see Figure 1).

Effi cient software modules

The comprehensive StuderGRIND pro-

gramming system is an example of this

type of modern grinding software. Its

modules support the machine operator

in a process-oriented manner and con-

sequently minimize the work prepara-

tion of component manufacture. The

operator can use the functions as re-

Vast potential: The

prototype system for EDM

dressing

L_Vortrag_V2_Fiebelkorn_E.indd 64 09.04.2009 18:07:56 Uhr

65MOTION 01/09

[1] Using specific grinding processes to increase productivity [2] Grain projection after dressing by EDM [3] Combined processes lead to economies in production

Combined processes

Another strategy for increasing productivity is to combine hard fi nishing pro-

cesses on a single machine. This enables the grinding process to meet the high

accuracy specifi cations for close tolerance with guaranteed process capability

and highly specifi ed surface fi nishes. Hard turning scores highly because of the

great versatility of its geometrically defi ned cutting edge. The combination of

the two processes offers the ability to select the most effi cient machining tech-

nique to suit the task in hand.

Combined hard turning and grinding has now established a place for itself for

the manufacture of gears in the chuck, for universal use and for the series

manufacture of precision components that need to be machined between cen-

ters or in a chuck.

Minimizing changeover times

The potential user can therefore choose between a number of ideal process

strategies for machining precision components. In each case, minimizing the

time spent changing over is a particular feature, particularly when batch sizes

are small. Toolholders, for instance, can be machined between driven centers

(see photo 3). It is therefore possible to start by turning both sides of the whole

contour including the tool changer fl ange, and then, without re-clamping, ac-

curately grinding the cones and fl at mountings with great process reliability

using measurement control systems. STUDER has been able to optimize the

internal machining of workpiece-specifi c toolholder bores equally well with

other types of holder with HSK interfaces. The process-specifi c steps of pre-

drilling and fi nish grinding of the bore have led to excellent bore quality param-

eters with deviations of 0.3 μm for roundness, 0.2 μm for straightness, 0.6 μm

for cylindricity and a mere 1.5 μm

for dimensional accuracy.

The philosophy outlined here of

combined hard fi nishing (grinding

and turning) expands the decision

matrix of production planners for

future production processes. It not

only enables hard turning to be

combined with grinding; it includes

milling with driven tools, hard

reaming and honing.

of the operator interface of external

modules such as sensor system pack-

ages, measurement control or handling

systems from third-party suppliers. The

signifi cance of these person-machine

interfaces for programming, setting up

and managing fi nish machining pro-

cesses is increasing all the time.

Productive carbide

machining

Alongside the various traditional meth-

ods, the technology of high speed grin-

ding for carbides and ceramic with

changing form elements on the work-

piece has distinct productivity benefi ts.

The diamond grinding wheels that are

used for this purpose generally have

ceramic or metal-based bonds. The dis-

advantage to be set against their high

wear resistance, however, is that of

dressing. It is very time-consuming and

expensive to profi le and sharpen these

tools, particularly if they have special

contour lines on the abrasive coating.

In cooperation with project partners,

STUDER has therefore initiated a re-

search project to develop a new profi l-

ing and sharpening process using spark

erosion (EDM – Electro Discharge Ma-

chining, see left-hand photo). Initial

studies and process tests have shown

positive potential for profi ling ability

and the creation of suffi cient grain pro-

jection for subsequent grinding (see

photo 2). Further studies will follow,

with a view to industrial application.

ABOUT THE SPEAKER

Dr Frank Fiebelkorn is Head of Product Development, Research and Technology at Fritz Studer AG in Thun, Switzerland

[1][1] [2][2] [3][3]

L_Vortrag_V2_Fiebelkorn_E.indd 65 09.04.2009 18:07:57 Uhr

66 MOTION 01/09


Double face grinding of transverse sides

In double face grinding of transverse sides, the infeed movement is made up of

two components performed by different machine elements: the grinding speed

and infeed speed running lengthways to the workpiece. The overlap-

ping of the infeed movements is responsible for the good

grinding results and evenness of tool loading. Most impor-

tant input parameters in double face grinding of transverse

sides with planetary kinematics are the grinding speed and

the grinding normal force in an axial direction. An increase

in the average grinding speed improves workpiece depth

pattern and surface, while an increase in grinding normal

force in an axial direction increases the depth of grain cut.

This has a negative effect on the surface quality. A decisive

part was played by selection of a suitable lubricant. This

made possible an increase in the metal removal rate by a

factor of three. Including automatic feeding and discharge of

the workpieces, there was an improvement in productivity over-

all of 200 per cent, while all the required tolerances for mass

High-performance ceramic material

has many outstanding properties:

it is very hard and very light, and is

highly resistant to wear, pressure and

heat. Consequently, this material can

be used in conditions where steel or

plastic would not work. In manufactur-

ing technical ceramics it is in particular

fi nishing, using product-specifi c grind-

ing and polishing processes, which

represents a decisive time and cost fac-

tor. Precision production grinding will

be described using four different grin-

ding processes:

Double face grinding of transverse

sides with planetary kinematics

Angular plunge-cut grinding with

centerless technology

Centerless grinding of pump rollers

Cylindrical grinding of ceramic

materials

Lec ture V-3 | May 8 , 20 09 | 15 .30

The fi nal polishIn precision grinding of hard and brittle high-performance ceramics under production conditions, everything depends on the design being suitable for ceramics.

Between centers: Grinding media being

ground on the KRONOS S

50 per cent less production time: Using a three-stage process in angular plunge-cut grinding, the

CeramTec specialists avoid inaccuracies

By Dr Carsten Russner

L_Vortrag_V3_Russner_E.indd 66 09.04.2009 18:12:19 Uhr

67MOTION 01/09

Cylindrical grinding

CeramTec today grinds ceramic insulators for the CFC zirconium oxide high-

performance brake in an HSG process on STUDER S32 machines at a grinding

speed of 125 m/s.

Here too, ceramic-bonded grinding wheels are used. The stock removal rate is

over eight mm³/mms and the G-ratio is better than 1,000. The tolerances achieved

in the diameter in ceramic mass production are less than six μm.

Hard grinding costs and accuracies

In general, the saying ‘the more accurate, the more costly’ does not apply. It

depends much more on a design suitable for ceramics, and the opportunities

these designs offer for hard grinding. Thus centerless plunge-cut grinding is to

be preferred to grinding between centers as in this way an intricate stage of

workpiece clamping is dispensed with. Admittedly this is at the expense of the

achievable tolerances, specially

in coaxial work. It may be as-

sumed that fast automation con-

cepts, higher grinding speeds

and higher grinding normal forc-

es will increase productivity by

a factor of ten. In the manufac-

ture of workpieces with toler-

ances in the μ range, new dress-

ing strategies will certainly play

a decisive role.

production were achieved. The trend is

away from grinding wheels with ex-

treme diameters in excess of 1,200 mm

and towards higher grinding speeds.

Angular plunge-cut grinding

Grinding media of Si3N4 are ground on

KRONOS S machines from MIKROSA.

On these machines, the previous

processing between centers can be sub-

stantially reduced. The grinding tool is

a diamond grinding wheel, while the

dressing roll is a newly-developed dia-

mond form roll from Messrs. Saint-

Gobain Winter. Neither of these has any

problem in maintaining the required tol-

erances. It is a major challenge however

to profi le the grinding wheel: wear of the

dressing roll cannot be measured. This

means that the CNC program miscalcu-

lates the corrections. This then results

in inaccuracies, and to avoid these, the

specialists from CeramTec AG divided

the process up into three stages:

Pregrinding the curved surface

Grinding the face and the

curved surface

Finishing grinding of the

curved surface

In this way, not only was a cmk-factor

of 3.86 achieved for the curved surface,

process time was reduced by 50 per

cent as well.

Centerless grinding

Extreme demands are made of pump

rolls in respect of their stress gradient.

The roll must fall logarithmically from

the center to the faces by 1.7 μm in or-

der to avoid extreme peaks of stress. If

it is required to achieve these gradients

in honing work, the preceding center-

less grinding with ceramic-bonded dia-

mond grinding wheels must lie within

a range of ± 0.002 μm. These toleran-

ces can only be achieved by grinding

in a clamp and the use of ceramic-bond-

ed grinding wheels dressed in the ma-

chine. Here, the dressing is of major

importance.

ABOUT THE SPEAKER

Dr Carsten Russner is Manager Innovation – Business Development in the business sector Systems Technology at CeramTec AG with a focus on product development

[3][3]

[1][1] [2][2]

The CeramTec product variety: [1] Seals made of various high-performance ceramics [2] Wear parts, ground

with a diamond grinding wheel [3] Various special components

L_Vortrag_V3_Russner_E.indd 67 09.04.2009 18:12:20 Uhr

Gauging and control for grinding machines

Leading...

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...results from the perfect combination

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L_Vortrag_V4_Graf_E.indd 68 09.04.2009 18:18:38 Uhr

69MOTION 01/09

Aluminum oxide

Aluminum oxide is made from melted bauxite, the basic material in the produc-

tion of aluminum. It is characterized by its white color and in particular by its

hardness and splintering ability. The purity grade lies between 98.5 and 99.5 per

cent. In order to increase the tenacity of aluminum oxide, chromium oxide in

quantities of 0.2 per cent (pink aluminum oxide) or up to 5 per cent (ruby red

aluminum oxide) is added to the melt.

Single crystal aluminum oxide

Single crystal aluminum oxide which is somewhat tougher and therefore splinters

differently to aluminum oxide is produced in a special process. Grinding wheels

made from single crystal aluminum oxide can achieve a very long service life if

used in suitable applications. But the main use of single crystal aluminum oxide is

as support grain and fi ller grain in CBN grinding wheels.

Sintered aluminum oxide

In the early Nineties, a process was developed to manufacture the smallest pure

corundum grains with an average diameter of between 0.0002 and 0.0025 mil-

limeters and to sinter them into blocks. The result was sintered aluminum oxide.

During a controlled sintering process only the grain boundaries of the nano-

Today, users of grinding machines

have a wide choice of abrasive ma-

terials at their disposal. Each of these –

whether aluminum oxide, sintered alumi-

num oxide, CBN or diamond – has a wide

variety of variants. They all have their own

specifi c uses and the crucial problem is

selecting the ideal grinding medium for

each task. Lot sizes, surface quality, fi re

prevention and dressing tool wear play

an important part in this decision.

Grinding media

The following abrasive types are mainly

used today:

Aluminum oxide and single crystal

aluminum oxide

Sintered aluminum oxide

CBN (cubic boron nitriole)

These varieties of corundum are classed

as conventional grinding media; they are

mainly used as a ceramic bond in preci-

sion grinding operations.

Lec ture V- 4 | May 8 , 20 09 | 16 .15

The ideal grinding mediumWhen choosing the best possi-ble grinding medium for a spe-cifi c application there are many parameters to be considered.

Ideal: The right

grinding medium

results in top product

quality

By Walter Graf


70 MOTION 01/09

GEF_10Jahre_210x287_UK_RZ.indd 1 27.02.2009 10:41:18 Uhr

amount of bond will allow higher

grinding performance. Sintered alu-

minum oxide is primarily used in

high- performance creep feed grin-

ding of diffi cult-to- grind materials

like Inconel. The disadvantage of ex-

truded corundum is that dressing

tool wear is particularly high.

CBN

The superabrasive grinding medium

CBN comes in many varieties. It is

available ceramically bonded, resin-

bonded, galvanically bonded and

metal bonded in monocrystalline or

microcrystalline versions, whereby

the monocrystalline version consists

of larger crystallites which break up

more coarsely with excellent, sharp

cutting edges. Microcrystalline CBN

behaves similar to sintered alumi-

num oxide. The crystallites are small-

er and only split under higher pressure. Today, the monocrystalline version is

predominant and ceramic and galvanic bonds have taken over.

Galvanically bonded CBN

Galvanically bonded CBN grinding wheels have a major advantage. They do not

require dressing, yet they achieve highly accurate profi les and surface qualities.

These results are guaranteed by the crushing process where the cutting edges

are fractured to size with a high-precision carbide roller. Regardless of bonding

variety or specifi cation, CBN grinding wheels should only be used on a high-

performance machine. Racing tires do not turn a medium sized vehicle into a

fast Formula One car.

When choosing the right grinding medium the

following issues should be clarifi ed:

1. CBN: yes or no?

2. Is the machine powerful enough?

3. Does it have a rotating dresser? If not, is the use of galvanically bonded CBN

grinding wheels to be considered?

4. Is the cutting speed above 35

m/s? (High Q’w values can only

be reached at ≥ 80 m/s.)

5. Is grinding oil an option? If yes,

does the machine have a

CO2-fi re extinguishing system?

Ultimately, there is not one ideal

abrasive but only the best possi-

ble abrasive for each particular

grinding task and economic re-

quirement.

sized grains are melted while the small

single grain remains as such. In theory,

this results in one billion grinding par-

ticles with an average crystallite size

of 0.0005 millimeter (0,5 μm). Sintered

aluminum oxide is available in four types

with different characteristics and per-

formance potentials:

Cubitron 321 (3M) for universal

applications

Cerpass 560 (Saint-Gobain) for

high grinding pressures

Cerpass DGE (Saint-Gobain) for

fl imsy, unstable workpieces

Cerpass TGE (Saint-Gobain) for

creep feed grinding, for Inconel etc.

The blocky grain shape of Cerpass 560

is particularly suited to grinding op-

erations with high grinding pressures,

such as pendulum surface grinding.

Cerpass DGE with its tapered grain

structure, on the other hand, is better

suited to grinding fl imsy, unstable parts

and internal grinding where rigidity is

limited due to the grinding quills. Rod-

shaped Cerpass TGE is in fact an ex-

truded grain. This grain shape allows

a very small amount of bond, as the

grain shape is building up a reinforced

wheel structure. With a high concentra-

tion of sintered aluminum oxide a small


ABOUT THE SPEAKER

Walter Graf is Chief Marketing Offi cer of the Winterthur Technology Group in Winterthur, Switzerland

Established: [1 + 2] Crushing of galvanized CBN

grinding wheel [3] Firm, medium and high toughness

of CBN grains

Sintered aluminum oxide: Cerpass 560 (Saint-Gobain)

for high grinding pressures and all grinding operations

Uncrushed

Steel base

Spread of grain sizes

[1][1]

3]3]

Crushed

Steel base

Spread of grain sizes

[2][2]


Maximum machine availability: with CNCs from Fanuc GEOur CNCs are the most reliable controls in the world: because statistics have demonstrated that the fi rst failure may not happen till 10 years have passed. This will save expensive services and reduce the TCO (Total Cost of Ownership) to a minimum. Your benefi t: highest reliability for maximum availability.

Just one of our strengths.

10 Years Production0 Failures100 % Availability

Fanuc GE CNC Europe S.A.Zone Industrielle / L-6468 EchternachTel.: (+352) 72 79 79 1 / Fax: (+352) 72 79 79 510 [email protected] / www.fanucge.com

Fanuc GE CNC UK Ltd. / 15 Basset Court - Loake Close Grange Park / UK-Northampton NN4 5EZTel.: (+44) 1604 7441 30 / Fax: (+44) 1604 7441 [email protected] / www.fanucge.co.uk

CNC CONTROLS DRIVE SYSTEMS LASER SYSTEMS SERVICE

GEF_10Jahre_210x287_UK_RZ.indd 1 27.02.2009 10:41:18 UhrL_Vortrag_V4_Graf_E.indd 71 09.04.2009 18:18:44 Uhr

Studer Mikrosa GmbH

Saarländer Straße 2004179 Leipzig, GermanyTel: +49-341-4971-0, fax: [email protected], www.mikrosa.com

Studer Schaudt GmbH

Hedelfi nger Straße 13770329 Stuttgart, GermanyTel: +49-711-4014-0, fax: [email protected], www.schaudt.com

Fritz Studer AG

3602 Thun, SwitzerlandTel: +41-33-439-1111, fax: [email protected], www.studer.com

Walter Maschinenbau GmbH

Jopestraße 5 72072 Tübingen, GermanyTel: +49-7071-9393-0, fax: [email protected], www.walter-machines.com

Körber Schleifring Asia-Pacifi c PTE. Ltd.

25 International Business Park#01-53/56 German CentreSingapore 609916Tel: +65-6562-8101, fax: [email protected]

Körber Schleifring Machinery Shanghai Co. Ltd.

Beijing Branch Offi ce

Room 10-04, CITIC Bldg. 19, Jian Guo Men Wai Da Jie Beijing 100004, ChinaTel: +86-10-6595-9934, fax: [email protected]

Schleifring Brasil Ltda.

Av. XV de Agosto, 5.060Sorocaba, Brazil, CEP: 18085-290Tel: +55-15-322457-26, fax: [email protected]

Körber Schleifring France

2 bis, Avenue du Président François Mitterrand91385 Chilly-Mazarin, Cedex, FranceTel: +33-1-697921-21, fax: [email protected]

Körber Schleifring Italia Srl

Via G. Garibaldi, 11822073 Fino Mornasco (CO), ItalyTel: +39-031-926-262, fax: [email protected]

Körber Schleifring GmbH – India Branch Offi ce

No. 99, Spencer Road, First Floor, Frazer TownBangalore 560 005, IndiaTel: +91-80-412504-25, fax: [email protected]

United Grinding Technologies, Inc.

5160 Lad Land Drive Fredericksburg, Virginia 22407, USATel: +1-540-898-3700, fax: +1-540-898-2811

United Grinding Technologies, Inc.

510 Earl Boulevard Miamisburg, Ohio 45342, USATel: +1-937-859-1975, fax: [email protected]

Körber Schleifring UK Ltd.

B13 Holly Farm Business Park, HonileyKenilworth, Warwickshire, Great BritainCV8 1NPTel: +44-1926-4850-47, fax: [email protected]@walter-ag.com

Körber Schleifring

Machinery (Shanghai) Co., Ltd.

No. 1128, Taishun Rd, Anting TownShanghai Jiading 201814, ChinaTel: +86-21-39587333, fax: [email protected]

Schleifring Service AG

Thunstrasse 153612 Thun, SwitzerlandTel: +41-33-439-1212, fax: [email protected]

Schleifring Service GmbH

Hedelfi nger Straße 13770329 Stuttgart, GermanyTel: +49-711-4014-100, fax: [email protected]

Körber Schleifring GmbH

Nagelsweg 33–35

20097 Hamburg

Germany

Tel: +49-40-21107-03

Fax: +49-40-21107-13

[email protected]

www.schleifring.net

Blohm Jung GmbH

Kurt-A.-Körber-Chaussee 63–7121033 Hamburg, GermanyTel: +49-40-7250-02, fax: [email protected], www.blohmjung.com

Jahnstraße 80–82 73037 Göppingen, GermanyTel: +49-716-1612-0, fax: [email protected], www.blohmjung.com

Combitec AG

Lengnaustrasse 12, 2504 Biel, SwitzerlandTel: +41-32-344-0450, fax: +41-32-341-0671 [email protected], www.combitec.ch

Ewag AG

Industriestrasse 4, 4554 Etziken, SwitzerlandTel: +41-32-61331-31, fax: [email protected], www.ewag.com

Mägerle AG Maschinenfabrik

Allmendstrasse 50, 8320 Fehraltorf, SwitzerlandTel: +41-43-3556-600, fax: [email protected], www.maegerle.com


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