Machining hard Materials using iMachining

iMachining for Super Alloys & Hard Materials

Amod Onkar – SolidCAM Ltd.

Titanium

Inconel

Stainless Steel

Stellite

Hastelloy

Tungsten

Prehardened Tool Steel (>45 HRC)

Hard Materials & Difficult to Cut Materials

Chip thickness variation

High heat Stress

High tool wear

Edge build up

Low thermal conductivity

Deformation process changes during machining

Getting the right cutting conditions

Challenges in Machining Hard Materials

Machining Influencers

CNC Machine

Fixture

Cutting Tool

CoolantCAM toolpath

SolidCAM iMachining – Ultimate Solution for Hard Material Machining

Increased productivity due to shorter cycles –

time savings 70% and more!

Dramatically increased tool life

Unmatched hard material machining

Outstanding small tool performance

4-Axis and Mill-Turn iMachining

High programming productivity

Shortest learning curve in the Industry

iMachining – The revolution in CNC Machining

The unique Technology Wizard provides optimal feeds and

speeds, taking into account the toolpath, stock and tool

material as well as machine specifications.

iMachining Wizard + iMachiningToolpath =

The Ultimate Solution!

http://www.solidcam.com/imachining/imachining-technology-wizard/

Used both for 3D surfaced and prismatic parts.

Optimized machining of each Z-Step, using proven

iMachining 2D technology

Deep roughing uses the whole length of the flute,

shortening cycle time and increasing tool life

Rest material machining in small upward steps, optimized

for constant scallop height, further shortens cycle time

iMachining 3D – Utilizing Proven iMachining 2D & Technology Wizard Algorithms

Intelligent localized machining and optimal

ordering eliminates almost all long positioning

moves and retracts

A dynamically updated 3D stock model

eliminates air cutting

Tool path automatically adjusts to avoid contact

between the holder and updated stock

Combined with HSM Finish, iMachining 3D provides

a complete machining solution for 3D parts.

iMachining Two Components

>> More info

iMachiningToolpath + iMachining Wizard = The Ultimate Solution!

+

http://www.solidcam.com/imachining/imachining-overview/

With traditional fixed "step-over" offset tool path, the cutting tool "steps over" a fixed

amount to cut the next row of material - this creates areas where the tool is subjected to

heavy forces, especially in tight corners.

CNC operators had to slow down the cutting operations and take very shallow cuts to

minimize cutting tool breakage and wear in these high stress areas.

The slow speed of the cut and the shallow depth of the cutter, are set for the entire

process - so the impact of even just a few problematic areas could severely slow the entire

process down and cause high rates of tool wear.

This also greatly lessens cutter life as only a small percentage of the bottom of the cutter

is used during shallow cuts.

Standard Offset Tool paths

Controlled Step Overs (no over loading the tool)

Exact Stock Machining (no air cutting)

Smooth Tangent Tool Paths

(Smooth Machining)

iMachining’s Intelligent Tool Path

iMachining Features

Unique Toolpath Pattern

Optimum automatic Cutting Conditions

Constant Cutting Force

Vibration Control

iMachining - Solomon’s Theory

First definition of HSM was proposed by Carl Solomon in 1931

He assumed that at certain cutting speed which is approximately “5-10” times higher than conventional machining, the chip tool interference temperature will start to decrease

iMachining – Transition & HSM Range

High Speed Milling temperature balancing process

Temperature Rises

Transition to plastic phase

Cutting force reduced

Less energy expended

Less Heat Produced

Temperature goes down

This sensitive sequence maintains a stable cutting temperature, due to its negative feedback, and therefore maintains stable high speed cutting

The stable high speed cutting is very prone to disruption if any of the influencing factors changes for some reason e.g. the air stream is temporarily blocked – the temperature rises uncontrollably and the tool breaks

This sensitivity of the temperature balancing process demands that to avoid collapse of the high speed cutting, a number of parameters have to be strictly controlled at their nominal constant values

First, iMachining intelligent tool paths manage the cutting angle (section of tool engaged

with the stock material).

When the cutting angle is properly controlled throughout the entire cut, the result

minimizes the forces on the tool, allowing the tool to cut much deeper without

excessive wear or breakage.

Deeper cuts, using all of the cutting tool length, require far fewer passes, greatly

reducing the cycle time of the part.

Also, since the entire cutting tool length is used, tools are no longer replaced with only

a small percentage of the bottom of the cutting tool used - Cutting Tool life dramatically

increases to many times that of a cutting tool used in a Traditional tool path.

Another major benefit is the ability to use small cutting tools, even for really hard

materials

iMachining Intelligent Tool path – Manage Cutting Angle

iMachining Intelligent Tool paths – Manage the Feed Rate

Second, iMachining Intelligent Tool Paths manage the "Feed Rate”

In iMachining, since the Cutting angle maybe constantly changing (morphing Spiral), the Feed Rate is adjusted in a manner that keeps a constant Chip Thickness.

This reduces or eliminates the uneven loading forces on the tool, that significantly reduce the life of the Cutting Tool - by having a constant and reduced load on the tool, tool life is greatly increased.

Cooling Cooling – Fluid or Air Cooling Design

Peripherals that influence HRSA Machining

Cutting Tool Cutting Tool – Sharp Corner/Chamfer/Corner Radius Tool Holding – Collet / HydroGrip / Power Chuck

Work Holding

Work Holding – Mechanical Vice / Hydraulic Vice/ Holding Fixture

Cooling plays a Pivotal role in machining

HRSA Materials

High pressure (>40 Bar) Fluid cooling must

be used for HSRA Materials

High pressure Air must be used for Steel (45

HRC & beyond)

Cooling

Ring Cooling Design for HRSA Materials

Use a cutting tool with maximum core

diameter (Reduces Deflection)

Use a cutting tool with Corner radius

(Sharp Corner increases chipping)

Use a Honed tool as it helps extend

tool life considerably

Cutting Tool

Tool Chipping Comparison

Courtesy – Sandvik Ltd.

Use of Hydrogrip / Shrink Fit / Power Chuck gives

following benefits

• Minimized runout which increases tool life

• Cutting Stability allowing for greater depth of cut

• High Clamping forces which prevent pull out of high helix cutters

Tool Holding

‘For every 10 microns in added run out the tool life reduces by 50%’!

When programming with the feed applied to the tool centre, the feed must be reduced when producing an internal radius or a circular motion (G2 or G3) if not using radius compensation.

This is done since the periphery has to travel further than the tool centre for the same angular rotation.

Slider at 100% means iMachining will maintain a constant Chip Thickness when cutting in corners.

Slider at 0% means iMachining will maintain a constant Feed rate between cutting G1 (Straight line) & Corner (G2)

Slider must be at 100% for Super Alloys

Feed Rate Control – Peripheral & Center

The following 3 images demonstrate the moat width with different tools in a slot of 25 mm Width

Effect of Moat Width

Slot Machined by 16 Dia End Mill Slot Machined by 12 Dia End Mill Slot Machined by 10 Dia End Mill

The toolpath with minimum movement while moating would wear the tool very fast

Machinability of a Material

Machinability is a term indicating how the work material responds to the cutting process. In the

most general case good machinability means that material is cut with good surface finish, long tool

life, low force and power requirements, and low cost.

Several definitions of Machinability is available, but in practice so called machinability index is often quoted

What is Machinability?

Km = V 60 / V 60R

Km = Machinability Index

V 60 = Cutting speed for the target material that ensures tool life of 60 minutesV 60R = Cutting speed of Reference material that ensures tool life of 60 minutes

Km > 1 machinability of the target material is better than that of the reference material, and vice versa.

The reference material for steels, AISI 1112 steel has an index of 1

Machining of this steel at cutting speed of 0.5 m/s gives tool life of 60 min

Therefore, V 60R = 0.5 m/s

The machinability index for SS 302 is Km = 0.23/0.5 = 0.46 (Tool life of 60 min for 302 SS is reached for cutting at 0.23 m/s)

The machinability index for AISI 1045 is Km = 0.36/0.5 = 0.72 (Tool life of 60 min for AISI 1045 is reached for cutting at 0.36 m/s)

So the machinability order would be:

AISI 1112 > AISI 1045 > 302 SS

Sample Calculation of Machinability

Improves tool life dramatically

Allows iMachining to decide on exact cutting conditions

Better Surface Quality

Reduces the chances of warpage

Improves overall process

Why is Machinability Important?

Physical properties of the work material

• The basic nature – brittleness or ductility etc.

• Microstructure

• Mechanical strength – fracture or yield

• Hardness

• Hot strength and hot hardness

• Work hardenability

• Thermal conductivity

• Chemical reactivity

• Stickiness / Self lubricity

Levels of the process parameters

Cutting tool - Material and Geometry

Machining environments (cutting fluid application, Work Holding etc.)

Factors Affecting Machinability in Real World Conditions

Sample Part – AISI 1045 Steel

Machine – Mazak FJV 10KW Spindle

Part Size – 100 X 75 X 50

Cutting Tool – Dia 12 End Mill (4 Flute , 45 Deg Helix)

Cutting Depth – 24 MM

Measuring the Machinability of a Material


Define a New Material with UTS taken from Test Chart

or from www.matweb.com

http://www.matweb.com/


Define a 2D iMachining toolpath at level 8 for

the geometry shown. Ensure to get Whole

Number ACP in order to prevent chatter

Note down the marked Values. Note that the

Power is shown as 5.2 KW for this Cut.


Calculate the TP & Generate the GCODE


Once the machining starts observe the

Spindle Load after 2 passes till the machining

ends.

Let’s assume the load was 60% which

translates to 6 KW on a 10 KW Spindle


As per the UTS of the Material we should have had

52% load on the spindle. 60% load means the

material is slightly tougher to machine.


Edit the material database and reduce the

machinability factor to about -16%



Edit the toolpath and enter the noted values

before the Machinability was modified. If we

get the power as 6 KW , We have exactly

determined the machinability of the material.

iMachining Forces on Spindle & Axis

iMachining Effect on Machine Tools

The iMachining Tool path, combined with optimum cutting

conditions provided by the Technology Wizard, ensure constant

load on the tool in any situation.

iMachining makes sure that the constant load on the tool will be

such that the spindle load will range from 4% to 17% of the

maximum possible spindle power load (depending on the LEVEL

of the slider in iMachining Wizard)

Hermle company concluded that with iMachining, the forces

acting on the their Spindle are the smallest of all CAM systems

using High Speed Machining.

Makino company also tested iMachining on its machines

(MAKINO A55 & A61) and reached similar conclusions

Cooperation of the University of Bohemia, Czech Republic

& SolidCAM focused especially on cutting force measurement

This University is equipped with several types of dynamometers:

Rotational cutting force dynamometer

Axial dynamometer for drilling operations

Work piece dynamometer

iMachining – Cutting Force Measurement

Designed for cutting force measurement of all types

of operations

Possible measured forces/directions:

• Components Fx, Fy, Fz

• Torque moment Mz

Position:

• Spindle

Rotating Dynamometer

Designed for cutting force measurement during

drilling and turning operations



• Torque moment Mz

Position:

• Machine table

Axial Dynamometer

Designed for cutting force measurement of all types

of operations



Position:

• Machine table

Work Piece Dynamometer

Data is transferred by shielded wire

PC is equipped by a measuring card

Every component is processed separately

Sampling: 10 000Hz

SW: LabVIEW

Data Measurement

Closed pocket with an island

Pocket depth 24mm

Material: Aluminium_100BHN (100HB)

End mill:

Diameter (D)= 8mm

Number of flutes = 3

Ap = 30mm (cutting length)

Ha° = 38°

iMachining level: 5 (Moderate)

Sample Part

Conventional Pocketing Strategy – Cutting Force

Classical pocketing

Feeds and speeds set according to the cutting tool manufacturer’s catalogue

Ap = 4mmAe = 7,2mmfz = 0,09mm

Yellow: Approach Green: Machining

iMachining – Cutting Force

Yellow: Approach Green: Machining

Feeds and speeds:

According to SolidCAM -

iMachining database

vc = 283 m/min (11250 rpm)

vf = 4507 mm/min (fz = 0,13

mm/tooth)

Test Objective - High Speed Machining of Titanium and SS By Using SolidCAM

iMachining generated Program with Kennametal Harvi 2 ER

D12 and D16 x R3 end mill.

Grade – KCSM15 Z-6.

Test Material - Stainless Steel & Titanium Blocks supplied by Major

Aerospace Company.

Machining - Periphery and Pocket machining.

Machine - Mazak FJV200 (12000 RPM ,Spindle Power 15KW Continuous)

Stainless Steel P660 & Titanium TiAl6V4 Trials - Kennametal

Stainless Steel P660 - Trials

Stock Size – 250 X 200 X 60

Roughing

1.Cutter : Dia 16R3 bull nose

DOC: 23mm

Vc= 171 ( RPM 3395)

Fz/tooth = 0.143 at level 4.

Finishing


DOC: 23mm

Vc= 205 ( RPM 4070)


Adapter –Shrink fit

withHSK63A backend

Cycle time – 3min 36sec

SS – Periphery Milling

Roughing


DOC: 23mm

Vc= 171 ( RPM 3395)


Finishing


DOC: 23mm

Vc= 205 ( RPM 4070)


Adapter –Shrink fit withHSK63A backend


SS – Pocket Machining

Titanium Machining Toolpath

STOCK SIZE - 200 X 175 X 50

Roughing


DOC: 20mm

Vc= 83 ( RPM 1857)

Fz/tooth = 0.143 at level 4 of SolidCAM



Titanium – Periphery Machining

Roughing


DOC: 20mm

Vc= 83 ( RPM 1857)

Fz/tooth = 0.143 at level 4 of SolidCAM



Spindle Load – 20%

Titanium Pocket #1 Machining

Roughing

1.Cutter : Dia 12R0.8 bull nose

DOC: 17 mm

Vc= 113 ( RPM 2997)


Finishing

2.Cutter : Dia 12 R0.8 bull nose

Vc= 83 ( RPM 4070)


Adapter –HP Chuck withHSK63A backend


Titanium Pocket #2 Machining

20 X Magnification

Tool wear – D12 on Titanium

Upto 0.1 mm Wear Observed on all Cutting Edges

iMachining Success

Customer: NIV Haritot

.

Material: Titanium

The customer had 75 pieces to produce

Standard cutting time:17 min / Piece

iMachining 2D = 3.5 minutes / Piece

Saving by iMachining : 80% saving

Total time saving for 75 parts : 16 hr 52 min

Component : Aerospace component

Material : Inconel 718

Machine : Hurco VMX50

Tools used : Dia 16 Chatter Free End Mills

Operation : iMachining 3D roughing

End Mill used : Chatter free end mill (Iscar Make)

Dia of End mill : 16

Ap : 33 mm

Ae : 0.3 – 1.49

Vc : 81 m/min (Iscar – 45 m/min)

Feed/ tooth : 0.101

Tool Life : 86 Mins (Iscar Estimate – 26 mins)

iMachining - Inconel

iMachining Success Stories

Burns Machinery - US

Material – Inconel 625

Machining Time savings – 75%

Tool Life - > 300%


Kline Oil Field Equipment - US

Material – Inconel 625

Machining Time savings – 86%

Tool Life - > 500%


Roku Roku - Japan

Material – Tungsten Carbide (90 HRC)

Competitor CAM – 42 hours (9 Tools)

iMachining - 54 Minutes (1 Tool)

Thank You !!

Date post:	18-Dec-2021
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Machining hard Materials using iMachining

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