OIPP_106082X_Tan Yee

School Of Engineering

Report on

Overseas Industrial Placement

Programme (OIPP) 2012-2013

by

Tan Yee (106082X)

at

JTEKT Corporation, Aichi, Japan

Tan Yee Page 2

Diploma in Digital & Precision Engineering

OIPP report for EGD326

Contents

1.Introduction ............................................................................................................................. 6

a. The Author/Student ............................................................................................................ 6

b. OIPP Overview .................................................................................................................. 7

2. Objectives .............................................................................................................................. 8

a. Learning Objectives ........................................................................................................... 8

b. Technical Project Objectives ............................................................................................. 9

3. Background .......................................................................................................................... 11

a. Overview of Pre-OIPP activities ...................................................................................... 11

a1. Understanding the Concept and Knowledge of Automated System (Robot) ............ 11

a2. Electrodes ................................................................................................................... 13

a3. Models for Jobs Sequencing ...................................................................................... 17

a4. Jobs Sequencing ......................................................................................................... 21

b. Description of Overseas Company and its Activities ...................................................... 24

4. Attachment Schedule ........................................................................................................... 26

a. Summary of Attachment Programme ............................................................................... 26

b. Gantt Chart indicating Milestones and Deliverables ....................................................... 28

5. Brief Description of Activities ............................................................................................. 30

a. Technical Description ...................................................................................................... 30

b. Areas of Work, Skills Needed, Skills Acquired .............................................................. 30

G Code NC Programming ................................................................................................ 30

CAD –Computer Aided Drawing (UG NX 7.5) .............................................................. 38

CNC Horizontal Machining ............................................................................................. 39

CAM – Computer Aided Manufacturing (UG NX 8.0, Vericut, Mill Plan 5 Axis, UHPC-

II)...................................................................................................................................... 39

c. Results/Activity Achieved ............................................................................................... 40

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Week 1 ............................................................................................................................. 40

Week 2 ............................................................................................................................. 43

Week 3 ............................................................................................................................. 46

6. Key Challenges faced and solutions proposed ..................................................................... 66

a. Technical Problems faced during attachment .................................................................. 66

b. Solutions Proposed and Outcome .................................................................................... 66

Appendix A .............................................................................................................................. 68

Objectives: ............................................................................................................................... 72

Hypothesis: .............................................................................................................................. 72

Theoretical Understanding/Background: ................................................................................. 72

Heat-resistant Alloy ............................................................................................................. 72

S48C (Carbon Steel) ............................................................................................................ 73

Ti6Al4V (Titanium Alloy) ................................................................................................... 73

Comparison of Technical Characteristics: ........................................................................... 74

Analysis of S48C and Ti6Al4V using Radar Chart: ............................................................ 75

Surface Roughness ............................................................................................................... 77

Tool Wear (Flank and Crater) .............................................................................................. 79

Task: ......................................................................................................................................... 80

Introduction .......................................................................................................................... 80

Cutting Condition................................................................................................................. 80

Cutting Test .......................................................................................................................... 81

NC Data ............................................................................................................................... 81

Equipments/Materials used: ................................................................................................. 82

Setup .................................................................................................................................... 82

Procedure ............................................................................................................................. 83

Pre-Cutting ....................................................................................................................... 83

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Cutting.............................................................................................................................. 84

Post-Cutting ..................................................................................................................... 85

Cutting Results: ........................................................................................................................ 86

Test Cut No 1 (Ti6Al4V condition 1) .................................................................................. 86

Test Cut No 2 (S48C condition 2) ....................................................................................... 86



Cutting Load Analysis: ............................................................................................................ 88

Graph.................................................................................................................................... 88

Discussion ............................................................................................................................ 88

Cutting Resistance Analysis: ................................................................................................... 90

Graph (Cutting Resistance Fx) ............................................................................................. 90

Discussion (Cutting Resistance Fx) ...................................................................................... 90

Graph (Cutting Resistance Fy)............................................................................................. 92

Discussion (Cutting Resistance Fy) ..................................................................................... 92

Graph (Cutting Resistance Fz) ............................................................................................. 93

Discussion (Cutting Resistance Fz) ..................................................................................... 93

Surface Roughness Observation and Analysis: ....................................................................... 94





Graph for Maximum Peak, Ry ............................................................................................. 95

Graph for Ten Point Mean Roughness, Rz .......................................................................... 95

Discussion ............................................................................................................................ 96

Tool Wear Observation and Analysis: ..................................................................................... 97

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Test Cut No 2 (S48C condition 2) ..................................................................................... 101

Test Cut No 3 (Ti6Al4V condition 2) ................................................................................ 105

Test Cut No 4 (S48C condition 1) ..................................................................................... 105

General Discussion ................................................................................................................ 110

Conclusion ............................................................................................................................. 111

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1.Introduction

a. The Author/Student

Tan Yee is a Malaysian student currently pursuing his tertiary studies in Nanyang

Polytechnic (NYP) for Diploma in Digital and Precision Engineering. He is from Malaysia,

born and raised in Kuching, the capital of the State of Sarawak. He picked up the major in

Precision Tooling and Component (PTC) as his elective. PTC specialization includes

modules such as Integrated CAD/CAM Technology and Product Innovation and Rapid

Prototyping. He is now in his final semester of studies and required to complete an industrial

attachment. The author is fortunate to be selected for Overseas Industrial Placement

Programme and attached to JTEKT Corporation in Aichi, Japan.

The author completed his primary and secondary studies in Kuching, Malaysia. He possesses

literacy for three languages – English, Chinese and Malay. Besides, the author also has strong

passion in Science and Mathematics. During the course of his studies in NYP, he acquired

engineering know-how in various areas by completing modules in Engineering Mathematics,

Engineering Mechanics, Aerospace Manufacturing Technology, Computer Programming,

Material Technology, Metrology and Quality Control, 3D Mould Design & Plastic Processes,

Microfabrication & Nanotechnology, Automation Systems, Mechanical & Fixture Design,

Manufacturing Information Systems, Conventional Machining Skills, CNC Machining Skills,

Computer-Aided Design (CAD), CAM programming, Shopfloor Monitoring & Control and

etc. During his first and second year, he also took German 1 and 2 for general studies and

further furnished it with Optional Elective (OE) 1 and 2 hence the author is able to read,

write, and converse in basic German.

The author would like to take this page to express his appreciation and gratefulness for this

once in a lifetime opportunity to take part in Overseas Industrial Placement Programme

(OIPP). He would like to thank Economic Development Board (EDM) and SPRING for

their sponsor along the course of this programme. He also likes to thank his family, friends,

lecturers, tutors, Personal Mentor (PEM) and supervisor for guiding him in his studies in

NYP and preparation for OIPP. Special mention to Miss Cheam Shuning (Supervisor), Mr.

Mark Lee, Mr. Zander Chang (PEM), Mr. Teoh Chye Huat, Mr. David Lim and Mr.

David Wong for making OIPP possible for the author.

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b. OIPP Overview

The Overseas Industrial Placement Programme is an advantageous programme which

gives the selected students the scarce opportunity to expose themselves to the real world

industry by applying the theoretical knowledge and practical skills they acquired from NYP

in some of the world’s top notch engineering giants.

This programme equips the students with hands on engineering experience where they will be

involved in the company’s industrial projects. The output can be delivered to the customers

or developed into a new technology which will subsequently be implemented in the company

or related industry. Students have the chance to immerse themselves in the intensive

industrial projects to learn and work with a group of senior engineers and professionals

giving them a better outlook on what to expect as an engineering graduate in the future.

During the course of internship, students also have the opportunity to determine their interest

in what engineering field they are going to pursue as they will swap in different departments

to take part in every stage of engineering process from initial planning to product realisation

to marketing as well as after sale service and maintenance.

By doing internship overseas, students tend to be more independent by performing and

managing daily chores like laundry, cooking and cleaning. Blending into new culture will

also impart students with broader and more globalised perspective as students develop social

skills to interact with people of different races and background. This is crucial as the quote

says “it takes two hands to clap”. An engineering student should not just equipped with

technical knowledge or skills as social interaction is equally important especially when it

comes to complete a task in a team.

During my stay in GF AgieCharmilles, I will be placed in the Wire Cut Electrical Discharge

Machining (WEDM) marketing department. Hence, I will be focusing on the Wire Cut EDM

machines regarding their purposes, applications and capabilities.

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2. Objectives

a. Learning Objectives

The learning objective for this Overseas Industrial Placement Programme attached to JTEKT

Corporation in Japan can generally be divided into four primary categories:

1. Technological Exposure

The prime objective was to allow the student to be exposed to the latest ultramodern

technology from the overseas company that the student had been assigned to. These

companies that were chosen for the students are top-notch companies that have been known

for their leading position in precision engineering industry for the 21st era, student was

expected to learn and master relevant knowledge and skills involving these technologies and

eventually bring them back to Singapore for good. This valuable exposure can be turned into

important intellectual asset to propel NYP and Singapore PE industry to next level.

2. Corporate Culture

Learning how to design an engineering solution in classroom by using formula is different

from how you do it in the industry where you have to find out customers’ needs and interact

with other engineers to achieve the best possible solution. The company might practice

special corporate habits or norms which contribute to their high reputable standing to be

chosen as the attachment company for the student. Student is expected to immerse in the rich

and unique corporate culture and to pick up the working ethics and how the co-workers

communicate and interact among themselves. This experience is nowhere to be found on

book except by walking into the culture itself.

3. Cultural Exposure

Japan is known to be advanced and innovative country. The way how they live their life is

reflected in their working ethics. For example how they organise their daily disposal to

different categories like plastic and PET, paper products, metal, glassware and burnable

products. This organised way of managing waste is mirrored in their working ethics where

most of the documents are arranged in such manner too. Bear in mind that this is only one

example. Experience, learn and adapt the local culture is particularly important as this enable

students to acquire intangible attributes like working in a team, self-discipline. With such

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good cultured absorbed, it will be useful to bring such attributes back to Nanyang

Polytechnic.

4. Self-Independence

This programme enables every student to solely live on their own while working overseas.

Not only do they have to manage their daily life with proper time management as well as

learning how to communicate with people from different countries with different

backgrounds, but also having to learn how to adapt oneself to a real working environment.

This allows the student to gain self-confidence and thus allowing oneself to express

individual ideas more effectively.

b. Technical Project Objectives

JTEKT Corporation is a well-known company for its industrial machines capable of

producing high quality products bundle with easy-to-use software to maximize time and cost

saving efficiency effectively to achieve the best for customers’ needs.

The project assigned for the student for his internship in JTEKT was to investigate and test

cut alloys and conclude the best cutting conditions. The comparison data and finalized results

will be concluded and stored in the company’s database for future cutting reference purpose.

As efficiency cutting is concerned for this project the objective lied on understanding features

and characteristics of several commonly used engineering alloys like carbon steel and

titanium alloy. The student was to carry research and study on the nature on the selected

materials and analyze them using the radar chart knowledge which the company has taught

the student. With this attainable analysis results students have to select the best cutting

conditions for cutting speed, feed per tooth, spindle speed, federate and type of cooling

channel. The student has to evaluate these cutting conditions based on study as well as

guidance from supervisor and other engineer in the working team. Student learnt how to input

the NC program into the machine, setting up machine and tool, zero set, simulate and operate

the milling process. The tool wear inspection and surface roughness measurement after the

cutting were as important as it determined if the cutting conditions selected were valid or vice

versa to conform to the objective for high efficiency cutting.

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Student also gained entry to work with actual industrial project to investigate efficiency

cutting for titanium castings. This finding will be sent as reference to Saudi Arabia customer

for which they will use the data to evaluate the capability of Toyoda machine to cut and

manufacture petroleum pump from titanium casting. The intensive involvement in this project

allowed student to be more familiarize with know-how on investigating and evaluating

efficiency cutting that aligned with the previous technical objective.

Besides efficiency cutting, student also learnt how to visualize and produce 3D modeling

based on drawings given. This activity has further furnished student’s basic CAD foundation

acquired from NYP. Student was also imparted with advanced CAM knowledge on how to

select cutting condition and simulate them prior to actual cutting for visualization and

troubleshooting purposes. The software used included the one student was familiar with

which was Unigraphics as well as Vericut and software solely developed by JTEKT – Mill

Plan 5 Axis and UHPC-II (Ultra High Precision Control). Unigraphics is mainly for

generating complicated NC code; Vericut for simulation purpose; Mill Plan 5 Axis to select

cutting parameters (include cutting speed, feed rate and spindle speed based on cutting

material, tool information and tolerance input); UHPC-II to improve machining performance

by improvise the NC cutting program which eventually reduce lead time and increase

precision.

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3. Background

a. Overview of Pre-OIPP activities

The student has completed a full term Final Year Project (FYP) prior to his departure for

OIPP. He was assigned to a title “Design and Development of Electrodes and Jobs

Sequencing for Automated Production Cell”. During the course of this project, the student

was attached to two supervisors – Miss Cheam Shuning and Mr Willis Chong. The project

commenced on 24 September 2012 and ended on 23 November 2012.

The tasks of this project can be divided into three sub categories:

1. Automated System

To understand the concept and knowledge of automated system (3R WorkMaster Linear)

to maximize the efficiency of production.

2. Electrodes Design

To study and review electrodes designs and create 2D drawings for machinist use.

3. Jobs Sequencing

Study and understand the concept of Automation, Production Systems, and Computer-

Integrated Manufacturing so as to provide simulation for jobs sequencing.

a1. Understanding the Concept and Knowledge of Automated System (Robot)

In the first phase of the project the student did research online and studied catalogue of the

robotic system for automated production cell. The robot used was 3R WorkMaster Linear.

It can be concluded that WorkMaster Linear is an automation concept that gives extreme

flexibility. By placing WorkMaster on rails, the changer unit can be made to serve a large

number of machines, and at the same time more space is created for magazines and

peripherals. It is an innovative solution offers by Agie Charmilles and 3R System to decrease

the use of labour at the same time maintain the accuracy and precision of transferring

machining commands from one cell to another. However the drawback being the exorbitant

startup cost which makes economic justification difficult for shop floor with tight budget.

WorkMaster Linear is made in such a way to maximize the efficiency for machining process

by utilizing a designed interface to exert automated command for the robot running on rail. It

can be customized to serve various machines at one time which very much depend on the

complexity of shop floor layout and manufacturing demand. Several designs of magazine are

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available. The basic variants are modular racks or rotating magazines, where the shelves are

matched to the pallet systems in System 3R’s wide range of products.

Typical fields of application are:

Milling – changing of workpiece and cutting tool

Grinding – changing of workpieces

Die–sinking EDM – changing of workpieces and electrode

Wire EDM – changing of workpieces

Technical Specification:

Transfer weight – pallet with workpiece 75 kg or 150 kg, electrodes 10 kg

X-, Z- and C-axes – AC servomotor

Linear axis – AC servomotor

Max stroke, X-axis, 1250 mm

Stroke, Z-axis – 1400 mm

Rotation, C-axis, 300 degrees

Linear axis motion – 4 to 20 metres

Power supply required: three-phase 400 V AC, 3.5 kVA

Air pressure required – 6±1 bar, 150 l/min

Interface - serial R232/422, M-function or parallel I/O

Option – ID system with/without automatic scanning

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Illustration 1: A WorkMaster Linear complete with modular magazine

a2. Electrodes

Electrical discharge machining is a machining method primarily used for hard metals or those

that would be very difficult to machine with traditional techniques. EDM typically works

with materials that are electrically conductive and can cut intricate contours or cavities in pre-

hardened steel without the need for heat treatment. EDM also applies for machining small

features which are hard to reach by conventional machining method like grinding.

Generally, the working concept of EDM can be seen as a series of breakdown and restoration

of the liquid dielectric in-between electrodes. Two metal parts will be submerged in this

insulating liquid are connected to a source which is switched on and off automatically

depending on the parameters set on the controller. When the current is passed on, an electric

tension is created between the two metal parts.

In order to start EDM, we need engineering drawing with clearly labeled dimensions, views

and details like spark gap, datum positions with relative to reference plane etc so the operator

or technician knows the parameters to machine out the electrode. To start the drafting, we

need to incorporate information in the drafting head like File Name, Mould No, Customer,

Drawn By, Logo, Raw Size, Spark Gap, Insert Name and so on.

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Illustration 8: Drafting Head

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Illustration 9: Drafting showing an example of electrodes in front, top, side and coloured 3D

isometric view.

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For the bottom view of the electrode, we have to specify the distance from respective

reference or datum plane.

X: Distance between the center of electrode to center of insert in y-axis.

Y: Distance from the base of insert to center of electrode parallel to x-axis

Z: Distance from the top of insert to first protruding flat surface of electrode (away from

chuck).

Illustration 10: Picture showing reference made correspond to X and Y axis.

X

Y

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Z

Illustration 11: Picture showing side view in reference to z planar.

a3. Models for Jobs Sequencing

In order to start animation for the sequencing of the automated production cell, we need to

have models representing the real unit in the cell. To model a unit, we need to take into

consideration which part should be made movable in order to allow motion during

simulation. Besides, some basic measurement should be done to keep the ratio of different

units in the cell to appear proportionate. Although precise numerical control is not involved

for the course of simulation, but animation should be rendered as closer as possible to the real

scenario.

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Illustration showing the assembly of an automated production cell:

Illustration 15 showing

1 Computer control unit

2 Carousel

3 EDM machine - F0 350 ms

4 Milling machine - Mikron HSM 500

5 Robot - 3R WorkMaster Linear

6 CMM (Coordinated Measuring Machine) machine - Wenzel LH65

Illustration 16: Computer Control Unit

This unit does not have any specific moveable part. Unit is rendered solely for illustration

purpose.

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Illustration 17: Carousel

Modeled accordingly to the level of tool/workpiece holder available. Make sure the part is

modeled in perfect circle so as when rotating it shows a symmetrical rotational motion.

Illustration 18: EDM machine - F0 350 ms

The machine is modeled such that the container of coolant is moveable (able to rise and

recess) and the header unit is movable to illustrate EDM process. Coolant must be able “flow

out” to represent the injection of coolant prior to the commencing of EDM process.

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Illustration 19: Milling machine - Mikron HSM 500

The sliding door of the machine must be able to open to facilitate the manual removal of tool

and workpiece. Tooling holder must be able to move forth and back during machining

process. For the computer unit, it should be made free to move front and back to give

machinist the best view into the transparent sliding door when operating the machine.

Illustration 20: Robot - 3R WorkMaster Linear

This unit must be made totally versatile in X, Y, Z axis as well rotational C axis. The robotic

arm should be able to extend and retract to reach for the tool and workpiece during the

process. Machine is rest on conveyer belt and is able to move back and forth.

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Illustration 21: CMM (Coordinated Measuring Machine) machine - Wenzel LH65

Probe must be made to move in X, Y, and Z axis to touch the workpiece for dimensional

a4. Jobs Sequencing

A series of command or executable program is needed to release jobs to the production cell in

sequence according to needs. In NYP, two software are used to run and maintain the

automated production cell – Workcenter and CellManager. Both of them are responsible of

translating desired job sequencing into the specific language for the robot. Robot will then

responds and transfer along the conveyor belt to carry out task. With the aid of the software,

robot will be able to coordinated and synced in the cell to ensure a smooth transition during

the production process.

Workcenter

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Illustration showing setup of Workcenter

Workcenter is responsible in the early preparation work. It is used to organize the list of

workpiece and tooling on the carousel. To make the organization job easier, every workpiece

or tool will be fitted to a chuck which comes with barcode identification. All workpieces and

tools have to be identified through the barcode and data is stored inside the workcenter

system. Administration of offset data is also done here. Any offset in the automated

production cell in reference to the default setting is also set here. For example, zero set of

placing the workpiece in milling machine must be offset accordingly to the height of the

chuck thickness.

CellManager

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CellManager will come in for execution after preparation. The software runs on graphical

interface which makes management easier. It has several colours and each representing a

state of each workpiece or tool. After each workpiece or tool is identified in Workcenter,

program to sequence each machining process is added to CellManager. CellManager can be

used to store various commands exported from different formats to support several machines.

It is responsible to control workpiece and electrode on the carousel and to transfer them to

respective machine according to the planned sequence. It has the flexibility to add job, stop

job and change priority.

Illustration

This is the jobs sequencing the student has simulated for this project. The sequence will start

with the 3R WorkMaster Linear move to the magazine to acquire the cutting tool then move

to the milling machine and fix the tool to tool holder automatically. The rear sliding door of

the machine will close as the robotic arm retract and cutting process will commence

(workpiece is preloaded in the machine). The robot will then move to the magazine the level

its arm to suitable height before it extends to reach and grab the EDM workpiece. Robot will

carry the chuck loaded with copper material and send it to EDM machine for sparking. While

waiting for the EDM process, robot will retrieve the milled workpiece from Mikron HSM

500 and transfer it to CMM for Quality Control (QC) check. One cycle of jobs sequencing is

thus completed.

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b. Description of Overseas Company and its Activities

Illustration: New integrated brand logo of JTEKT Corporation implemented on 1 January

2012

JTEKT Corporation TYO: 6473.T is a Japanese multibillion corporation founded on January

2006 upon the merger of two companies: Koyo Seiko Co. and Toyoda Machine Works.

JTEKT Corporation belongs to one of the Toyota Group subsidiaries. The corporation

focuses on wide range of engineering products and solutions, mainly Steering Systems,

Driveline Components, Machine tools, Home accessories, and Ball & Roller Bearings.

JTEKT Corporation is headquartered in Osaka, Japan and has 40,756 consolidated employees

to date.

The integrated brand logo is designed to express how the company’s three business brands

are positioned and to clarify their integration. Behind it lies the commitment of KOYO, a

manufacturer of bearings that facilitate industrial development, TOYODA, a manufacturer of

machine tools, and JETKT, a system supplier that also operates an automotive parts business,

to contribute to a rich and abundant society through reliable technical capabilities. The design

of the central lines forming the letter “T” is based on the ancient Greek word “Tekton”

meaning a person who possess superior technical skills, i.e., technology), from which the

name JTEKT is derived.

Before JTEKT Corporation was founded, Toyoda Machinery had set up an overseas office in

Singapore in 1992. 3 years later in 1995 Toyota Machinery set up another consolidated office

in Bangkok, Thailand as Toyoda Machinery S.E. Asia Co., Ltd. Toyoda Machinery lands its

footsteps in South East Asia aims at delivering high quality of Toyoda’s machines and

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services closer to global customers. The office in Bangkok is capable of holding about 300

spare parts in inventory for customers. The company also actively utilizes local employees by

giving training.

Below is a timeline showing Toyoda Machinery S.E. Asia Co., Ltd. Milestones:

1941 : Toyoda Machine Works, Ltd., founded in Japan

1955 : Technical tie-up for cylindrical grinder production formed first transfer

machine in Japan completed

1966 : Production of semicinductor pressure transducers begun

1968 : Production of machining centers begun

1972 : Sales of programmable controllers, TOYOPUC begun Production of

CNC/CBN cylindrical grinders begun

1992 : Toyoda Machine Works, Ltd., Singapore Representative Office established in

September 5

1995 : Toyoda Machine Works,Ltd., Bangkok Representative Office established in

September 6

1996 : Toyoda Machine Works(Thailand) Co., Ltd. Established in Thailand

(presently JTEKT Automotive Thailand Co.,Ltd.)

2000 : Basic agreement with Koyo Seiko Co., Ltd.Regarding electric power steering

joint development

2000 : Production of electric power steering begun

2002 : Toyoda Machinery S.E. Asia Co.,Ltd. Established in November 18

2005 : Koyo and Toyoda argeed to merge

2005 : TMSEA Jakata Representative Office established in October

2006 : JTEKT Corporation founded

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4. Attachment Schedule

a. Summary of Attachment Programme

Date Activities Supervisors

9th January 2013 Departed from Singapore Changi Airport. -

9th of January 2013

Arrived at Nagoya Airport, Japan.

Fetched by company representatives

Guided tour around company and

plants

Mr Uchida

10th – 11

th January

2013

Assigned to the Cutting Group

Machining & Process Development

Office

Training schedule planning

Lecture on basic know how of cutting

technology

Mr. Hiroyuki Nakano (Cutting

Group Office Manager)

Mr. Hisashi Ohtani (Cutting Group

Assist. Manager/Supervisor)

14th – 18

th January

2013

Lecture on safety guidance

Instruction and learning for NC

program

Setup and manual input NC program

to machining center

Mr Simuzawa

Miss Yamamoto

21th – 25

th January

2013

Provide radar chart for selecting

appropriate cutting conditions

Study the knowledge for selection of

tool and cutting condition as well as

JTEKT high speed processing

technique

Select cutting parameters for shoulder

mill for S48C and Ti6Al4V

Create NC program for test cut

Prepare and setup machining center

prior to cutting

Mr Hisashi Ohtani

Mr Toda

28th January – 1

st

February 2013

Test cut and collect different cutting

results based on selected condition Mr Hisashi Ohtani

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Report and analysis on cutting results

Study new cutting project by Saudi

Arabia’s customers (material study on

KHR45A, KHR45A (800°C),

KHR35CT, KHR35CT-HiSi and

SUS304)

4th – 8

th February

2013

Measure the surface roughness of the

milled surface of Ti6Al4V and S48C

Complete and finalize report for

cutting Ti6Al4V and S48C

Cut stainless steel cast KHR35CT

based on the given cutting conditions

Compile report on the cutting results

of stainless steel casting KHR35CT

Mr Hisashi Ohtani

27th – 31

st of

August 2012

Assigned to the Apprenticeship

Department. Mr. Stephen Huber

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b. Gantt Chart indicating Milestones and Deliverables

Final Year Project (Prior to departure)

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5. Brief Description of Activities

a. Technical Description

The student was assigned to a project title “Understanding the Feature of Titanium Alloy

and High Efficiency Cutting”. The project was commenced on 10th

January and ended on

25 February.

Intern also assigned to second task on cutting stainless steel cast to investigate the capability

of Toyoda machine to manufacture petroleum pump. This is a real industrial project by Saudi

Arabia customer. If test cuts statistics turn out optimistically, Saudi Arabia may purchase

machines from Toyoda.

Besides the main activities, students also involve in courses and activities to acquire

engineering knowledge. These include NC programming course, several lectures on cutting

knowledge (basic know-how of cutting, selection of cutting condition, tool selection and so

on), CAD and CAM practices.

b. Areas of Work, Skills Needed, Skills Acquired

G Code NC Programming

Student attended a two day “Machining Center Programming Course” and has successfully

completed with certificate awarded. The course has further furnished the student knowledge

on G code as well as general used M code. The lesson was coached by Miss Yamamoto from

Service Department. An instruction manual on programming was given two days before the

course and asked to glance through prior to lesson.

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Programming manual by JTEKT

Lesson was divided into 7 topics:

1. Machining Center Outline

2. Programming Outline

3. Programming Fundamentals

4. Fixed Cycles

5. G43/49 Tool Length Offset

6. G40/G41/G42 Cutter Radius Compensation

7. Subprograms

Machining Center Outline – Here the basic fundamentals of machines’ axis movement and

origin ideas were recapped – the X, Y, Z and rotational B axis. The axis movement for

standard specification is shown as table below:

Axis Axis movement Axis movement direction Origin (zero)

X

Longitudinal

movement of

column (viewed

from the spindle

head side)

Left toward (+) direction

Center

Right toward (-) direction

Y Vertical

movement of

Upward (+) direction (+) end

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spindle speed Downward (-) direction

Z

Cross wire

movement of

table

Advance (+) direction

(+) end

Retract (-) direction

B Table rotation

Clockwise (+) direction

------------

Counter-

clockwise (-) direction

The student also been taught on the machine specifications like federate (minimum and

maximum), spindle (minimum and maximum), weight, performance (accuracy,

repetability…), no. of tool holders and so on of Toyoda machines but mainly focus on FV

series.

Programming Outline – Before making a program for machining center, the student must

first understand why such program was needed. In the context, it defined that – “machining

center is a numerically controlled machine which can perform various types of machining on

more than one surface without having to uncap the workpiece. And it is equipped with

automatic tool change or automatic tool selection function.” So the programming the student

was doing aligned with the NC (numerical control) unit where automatic operation was

permissible without operator’s intervention. To achieve that, study the different language of

programming enable the student to outline a complete and working chain of codes. The

programming flow can be explained in the following steps:

Tan Yee Page 33



Programming Fundamentals – Command used to control an NC machine tool maybe

considered to be constituted as follows:

Device to move

Direction to move

Amount to move

How

Numerical value specified following address G defines the mode of operation in which the

block of commands is to be executed. G codes are classified into the following two

categories:

One-shot G code Modal G code

The programmed G code is

effective only in the

programmed block.

The programmed G code remains

active until another G code in the

same group is programmed.

Examples of commonly used G codes are:

G90 – absolute movement

G91 – incremental movement

G28 – Origin position

G30 – Automatic tool change

G02 – Clockwise circular interpolation

G03 – Counterclockwise circular interpolation

Determination of Cutting

Order

Determination of Cutting Conditions

Making process Sheet

Punching NC Type

Tan Yee Page 34



Apart from G codes, there are other codes we used in programming:

F code (Feedrate) – A rate of axis feed per minute is commanded by numerical value

specified following address F

S code (Spindle Function) – It is used to designate the desired spindle speed up to five

digits

M code (Miscellaneous Function) – Two-digit or three-digit numbers following M turn

on and off the contact points of the PLC (programmable logic controller) inside the NC

to execute the sequence of the spindle rotation and tool change.

Fixed Cycles – The fixed cycle allows a series of machining such as positioning, drilling,

boring, tapping to be executed by a block of commands. This not only simplifies

programming but also reduces total length of part program tape. The illustration shows the

fundamental axis movement in fixed cycle.

Axis movements:

1. Positioning by X and Y axes

2. Positioning of Z axis at R point level by rapid feed

3. Cutting feed

4. Predetermined operations at hole bottom (G04, M05, M04, etc…)

5. Return from the hole bottom to R point level (G00 or G01) … G99 mode return up to

initial point level (G00) … G98 mode

1

2

3

4

5

G98

Initial point (for positioning)

G99

R point level

(cutting starting level) Z point level (cutting end level)

Tan Yee Page 35



G43/49 Tool Length Offset - The tool length offset function is used for compensating the

length of the tool. Axis movement amount of Z axis is changed by the amount set as offset

data to position the tool tip point at the commanded coordinate point. Difference between the

reference length (program tool length) used when making a program and the actual tool

length (setting tool length) is set as the tool offset data and this amount is added to or

subtracted from the programmed Z axis movement amount. The picture below shows how to

insert tool length offset into the G code program.

G40/G41/G42 Cutter Radius Compensation – The cutter radius compensation function

creates tool paths offset from the programmed tool shape by the preset offset (compensation)

amount. Highly accurate side face cutting (outside and inside walls), true circle cutting, etc.

are possible with an end mill using this function. Usually, program made is assuming zero

Tan Yee Page 36



cutter radius and tool paths are created with the cutter radius, preset as the compensation

amount, offset from the programmed path.

In the illustration above, when cutting workpiece of shape (1) with a cutter whose radius is

(R), the path along with the cutter center should move must (2) be precisely offset from the

programmed shape (1) by radius (R). The function to create paths away from the

programmed shape by the preset amount is called “offset”.

Subprograms – Fixed sequences and patterns which will be used repeatedly can be stored in

memory as subprograms and called out from a main program to execute them when

necessary. When a program is made using the subprograms, program itself will be made

shorter and tape preparation time will be reduced considerably.

For the machine we were using, we used FANUC 16i, 18i format. The format goes by M98

P_ _ _ _ _ _ where the first three digit is number of repetitions, last three for subprogram no

and M99 at the end of subprogram to end the command.

Several practices were given to let student understand how to compose G code for machining

purposes. Pictures below show when the student was simulating the program to troubleshoot

for error.

Workpiece shape to be cut

z

(1) (2)

Tool center path

Center radius (R)

Tan Yee Page 37



The student took a test upon completion of the two day programming course with achieved

score of 94%. The test was to test student understanding for G code programming on how to

define position in reference to machine coordination, ability to troubleshoot error and make

appropriate correction, know how to calculate certain parameters like spindle speed and feed

rate. A certificate was then awarded after the test.

Pictures showing the test answering sheets.

Tan Yee Page 38



Certificate awarded

CAD –Computer Aided Drawing (UG NX 7.5)

The student was given a basic training on Computer Aided Drawing (CAD) by modeling

several models. From basic understanding like sketching to realization of 3D model using

functions like extrude to advanced features like Draft Angle and Revolve were intensively

involved.

Pictures showing the drawings for CAD practice.

Tan Yee Page 39



CNC Horizontal Machining

CNC machining is the main focus of this internship where most attention was given. Student

has an opportunity to hands-on on Toyoda horizontal milling machine model FH550SX. The

training and skills acquired throughout the 7 weeks on this machine were:

Able to input data into machine system by MDI (Manual Data Input)

Able to edit program on the machine

Zero set in reference to workpiece and machine position

Simulate cutting using Optional Block Skip mode and offset from the real cutting

position

Cut workpiece in Single Block Mode

CAM – Computer Aided Manufacturing (UG NX 8.0, Vericut, Mill Plan 5 Axis, UHPC-

II)

Student learnt how to do Computer Aided Manufacturing (CAM) by learning how to

calculate and input cutting parameters into data sheet prior to simulation. These cutting

conditions or parameters are very important as they will determine the best NC program to be

input in the machine for cutting. The software which the student hands-on include:

UG NX 8.0 (Unigraphics)

To input cutting parameters like spindle speed, feederate, finishing tolerance and

cutting method to create NC program for machining. Simulation is possible prior

exporting the program.

Vericut

NC program verification and machine tool motion simulation module. NC program

export from UG can be simulated using Vericut. NC program can be optimized to

shorten processing time, extend tool life, improved surface quality, checked the cut,

due to cut, to prevent machine collisions, over-travel and other errors. A real three-

dimensional solid display, you can measure the size of the cutting model, and can

save the cutting model for testing, follow-up machining processes.

Mill Plan 5 Axis

A CAM software developed by JTEKT. Able to auto calculate cutting conditions

based on selected parameters like intended finished surface roughness, biggest and

smallest cutting radius.

Tan Yee Page 40



UHPC- II (Ultra High Precision Control)

A built-in software that comes with every purchased JTEKT machine. State-of-art

technology capable to automatically analyze NC program and improve it to provide

better finished cutting surface. It can improve precision needs and reduce machining

time.

c. Results/Activity Achieved

Week 1

Upon our arrival on the first day, the student was brought to tour around the showroom,

machining center and the five main plants of JTEKT Corporation in Kariya-shi (City) of

Aichi Prefecture. Student was introduced to the machine which was going to be used later for

training as well as other machines by Toyoda.

Firstly, E500H a horizontal spindle machine capable of performing cutting in X, Y and Z

axis. In Toyoda this machine is basically used to manufacture cylinder block for automotive

engine part of Toyota vehicles.

0

100

200

Without UHPC UHPC

10 1 15

10

200

156

Cutting time, (h)

Total Machinning Time

Cutting

Creating NC Pogram

Program Design

225 Hour

167 Hour

Tan Yee Page 41



Toyoda E500H

Next to another machine named Lineam which is also a similar horizontal machine but the

production outputs are for aerospace components (SAM is one of the customers), agriculture,

gas & petroleum engine parts besides for vehicles. KH400J and FV1365S which are

horizontal and vertical machine respectively. FH1250SX is the biggest horizontal machining

center in Toyoda capable of travel up to 2200mm in X-axis and has tool magazine capacity

up to 330.

FH1250SX

Toyoda turning grinder G32 is a manual hydraulic grinder capable of performing GOP

(Grinder Outside Planar). GE4 is another similar grinding machine but based on CNC

(Computer Numerical Control) interface. Koyo has this interesting machine which the student

has not seen before which is KCL-50S a centerless grinder. The workpiece is sandwiched in

between two rotating grinder and thus there is not support in the center. This machine is

capable of grinding two features: Outside Diamter (OD) and flange. Next the two shaft

grinding machines – GF32M and GC20M. GF32M is a CNC machine capable of cutting

crank shaft at 2 axis (C and X axis) concurrently. According to supervisor, Toyoda accounts

Tan Yee Page 42



60% of global crank shaft production. The latter GC20M is a cam shaft grinding machine.

Cam means the shaft is not cut to circle.

GF32M and GF20M

The author also visited the five main plants in JTEKT Corporation. The first plant was meant

for assembly of grinding and cutting machine as well for machining part center. Second plant

was for assembly and machining parts. Third and fourth are for automotive assembly. Fifth

also the last plant was for assembly of machining center. JTEKT corporation could produce

around 1220 machines annually, which can further breakdown into 360 grinding machines,

500 machining center and 360 cutting machines.

A lecture was given to the student on Thursday (10 Jan 2013) on the topic basic know how of

cutting. The author learnt about manufacturing methods like several forming processes –

press, forging, casting, rolling as well as removing stock methods like electrostatic discharge,

etching and cutting. He recapped what he has learnt in NYP for the definition of cutting and

grinding like the relationship between the cutting force applied and cutting angle. He also

revised several cutting parameters like spindle speed, cutting speed and feed rate. Making a

perfect cut is not just about the technical skill, proper selection of material for cutting tools is

equally crucial. In the context given, the author studied about properties of commonly use

cutting tools’ material. For example – steel, alloy steel, high speed steel, carbide, ceramic,

cermet, diamond, CBN (Cubic form of Born Nitride) and so on. Characteristic of the cutting

remaining (chips) can be used to determine the quality of cut, whether the cutting is well

done or vice versa. The pattern of the chips is also highly dependable on feed amount, cutting

angle and speed.

Tan Yee Page 43



Week 2

The student was given the task to study the properties and characteristics of two cutting

materials – titanium alloy, Ti6Al4V and carbon steel, S48C. A comparison table was made as

shown:

Ti6Al4V S48C

Composition

It has a chemical composition of 6%

aluminum, 4% vanadium, 0.25%

(maximum) iron, 0.2% (maximum)

oxygen, and the remainder titanium.

It has a chemical composition of 0.45-

0.51% carbon (maximum), 0.15-

0.35% of silicon, 0.60-0.90% of

manganese, up to 0.030% of

phosphorus and maximum 0.035% of

sulphur. The remaining will be iron.

Material Characteristics

Stronger than pure titanium

Good stiffness and thermal

properties

Excellent combination of

strength, corrosion resistance,

weld and fabricability

Used in application up to 400

degree C

Density of 4420kg/m3

Young’s modulus of 110GPa

Tensile strength 1000MPa

Hardness value (Vickers

hardness) of 349

Extension at 14%

Thermal conductivity of 6.7

W/m-K

Specific heat capacity of 0.5263

Malleable and ductile

Low tensile strength at 585 MPa

Hardness can be improved by

carburizing (heat treatment)

Density of 8000 kg/m3

Young’s modulus 210GPa

Hardness value (Vickers

hardness) of 170

Extension at 12%

Thermal conductivity of 51.9

W/m-K


Cutting Characteristics

Low cutting speeds

High feed rate

Generous amount of cutting fluids

Using sharp tools

Have rigid setup

Generally soft easier to machine

Prolong tool life with increasing

cutting speed

High feed rate

Less coolant required

Over rigid setup might dent

workpiece

Tan Yee Page 44



Student also attended a safety lecture on Tuesday by Mr Simuzawa from General Affair

department. There are five principles to follow strictly in company:

1. Value life

2. Stay healthy and safe

3. Keep others safe

4. Lead a happy family lifestyle

5. Eliminate unnecessary waste

In JTEKT, employees’ safety tops the priority of all agendas. The company wants to ensure

the welfare of every employee is guaranteed and thus rules and regulations are set to be

followed.

Prior to commencing of work, one has to thoroughly study about the work procedure. Work

procedure is designed in such a way to maximize the efficiency of machining center at the

same time maintaining the safety of operator. One also has to be alert at all time when

operating machine to lower or eliminate the risk of accident.

In JTEKT, there is a 6S practice:

1. Seiri (Organise)

2. Seiton (Arrange)

3. Seiketu (Hygiene)

4. Seiso (Cleaning)

5. Situke (Discipline)

6. Sikkari (Consistency)

6S practice will ensure a clean and neat workplace to work with which will eventually

improve production output and quality.

Safety suits in the company include hat, goggles, safety boots and mask. The combination of

different suits is to be put on during work depending on the nature of work place.

When encounter difficulties in work, it is advisable to troubleshoot. Troubleshooting starts by

terminating any immediate work and call for help from leader follow by his/her instructions.

Do not judge on your own if do not familiar with the situation. Doing so might further

jeopardize the situation.

There are two types of safety plates in the company:

Tan Yee Page 45



Working

When this plate is hung on the machine, it means the plate owner is operating the machine.

Do not interrupt the machine and make sure the power is always on.

Trial Run

Whenever we see this plate it signifies that the machine is on dry run or simulating the actual

cutting where further fine-tuning is required. Others are not permissible to interfere with the

machine unless inform the operating office otherwise.

When transferring workpiece or load from one point to another we are only allowed to carry

maximum weight up to 20 kg. To maximum the efficiency of transferring load, use light

container. When cart is used, push instead of pull as pushing allows one to see the goods in

front of you and thus can observe the load on the cart.

Safety work culture in JTEKT is quite different from the working ethic in Singapore. For

example, we cannot insert our hands into pocket when at work. This is to ensure we can react

according when accident happens, for instance if we fell down we can extend our hands to

render support. We are also not allowed to use cell phone when walking. If wants to make or

answering call, stop walking and do so.

The student recapped what he have learnt in NYP and learned new NC commands for making

program for FANUC vertical machine FV series. His lesson was coached by Miss Yamamoto

from Service Department. Instruction manual on programming was given one week prior to

lesson and student was asked to glance thru the contents.

Programming manual by JTEKT

Tan Yee Page 46



Lesson was divided into 7 topics:

8. Machining Center Outline

9. Programming Outline

10. Programming Fundamentals

11. Fixed Cycles

12. G43/49 Tool Length Offset

13. G40/G41/G42 Cutter Radius Compensation

14. Subprograms

Please refer to G Code NC Programming on details.

Week 3

This week the student learnt to draw a radar chart to compare the properties of two materials.

Based on the comparison made, he could easily select the appropriate cutting condition for

the raw material selected .

First of all, values for required properties as shown below needed to be jot down:

Calculation was made based on the selected parameters:

Hardness : 349/170 = 2.05

Tensile strength : 1000/585 = 1.71

Extension : 14/12 = 1.17

Properties Ti6Al4V S48C

Hardness (Vickers hardness,

HV) 349 170

Tensile strength (MPa) 1000 585

Extension (%) 14 12

Density, ρ (kg/m3) 4420 8000

Thermal conductivity, K

(W/m-k) 6.7 51.9

Specific heat, C (J//kg.K) 0.5263 0.4860

Heat characteristic value (K

ρC)^-0.5 8.01x10

-3 2.23x10

-3

Tan Yee Page 47



Heat characteristic value : 8.01x10-3

/2.23x10-3

= 3.59

Radar chart was plotted based on the calculate values:

Student attended lecture on tool and cutting condition selection as well as JTEKT high speed

processing technique taught by his supervisor Mr Hisashi Ohtani. The learning outcome:

Tool Selection – There are few parameters to look into when selecting tools.

1. Tool Shank

We used “Round Bar Deflection” to detect the deflection amount which will incur on

tool with the formulae:

Where P : Load, L : Length, D : Diameter and E : Young Modulus

So to decrease the deflection or to increase tool rigidity we will increase the young modulus

of selected tool. For example, we will select carbide over steel as carbide has better young

modulus at 72000kg/mm2 compared to steel which only has 21000kg/mm

2.

Besides, diameter of the tool shank is also crucial in deciding cutting condition. We have one

formula which is Length/Diameter to determine the suitable material for tool shank. If L/D is

bigger than 3 it means it will be difficult to initiate cutting whereas below means the cutting

will be easier. So usually diameter under 30 we will use carbide; for diameter over 30 we will

usually select iron-based shank as carbide is expensive for oversized tool shank.

0

1

2

3

4hardness

tensile strength

extension

heatcharacteristic

value

Radar Chart for S48C and Ti6Al4V

S48C

Ti6Al4V

Tan Yee Page 48



2. Optimum Tool Radius

For the most effective removal of material, mold/material corner, r must be equal or

close to tool radius, R. To calculate the amount of material removed from selected

cutting radius, formula as below is used:

√

Where is stock to remove, f is edge feed, R is tool radius and r is corner radius

3. Cutting Resistance at the Corner

Usually we will encounter cutting resistance especially when cutting at the corner, we

can reduce the resistance by increase the feed rate.

4. Number of Edge (Teeth) in Contact

It is important that the number of edge is constant during cutting. If the number of edge

in contact is not constant, vibration might incur and thus affecting the accuracy of

cutting.

Tool center

locus

Tool Acute-angled

corner

Tan Yee Page 49



5. Tool Shape and Number of Edge

The number of edge in contact with cutting surface must always be constant to reduce

vibration.

6. Tool Nature

It is important to select the right material for tooling to meet different cutting condition.

Tool which is made of better hardness and capable of withstand deflective and chipping

resistance is more preferred. However selection of tool material must be aligned with the

budget available thus economical justification plays a crucial role.

After selecting the correct tool, the tool must be handled with care to prolong its tool life.

This is equally important as how the tool is selected. During machine operation, tool may

encounter extreme conditions such as frictional heat, cutting resistance, machine vibration

and so on. In order to counter these negative effects, certain cutting parameters need to be

Not in

contact

Optimised

Tan Yee Page 50



adjusted in order to prolong the tool life. For example to tune down the cutting speed, shorter

cutting distance, adequate use of coolant.

Selection of Cutting Condition – This includes all the adjustable cutting parameters prior to

cutting process. Better surface finishing can be achieved with optimal cutting condition.

These parameters include spindle spinning rate, feed speed, feed amount and pick speed.

1. Spindle spinning rate

It is very much dependable on the limit of the machine feature. Advisable maximum

spindle speed input is up to 80% of the maximum. The same applies to the cutting tool,

ie the maximum spindle rate which the tool can take.

2. Feed speed, feed amount, pick speed

Material and cutting process type – roughing or finishing. It can also affect the asperity

of the finished surface.

Besides adjustable cutting parameters, chatter vibration is also one of the complications to

look into seriously. Chatter is defined to correspond to the relative movement between the

workpiece and the cutting tool. The vibrations result in waves on the machined surface. There

are mainly two causes for chatter to happen:

1. Forced vibrations are mainly generated by intermittent cutting (inherent to milling) due

to power disturbance, runout, or vibrations from outside the machine.

2. Self-generated vibrations are related to the fact that the actual chip thickness depends

also on the relative position between tool and workpiece during the previous tooth

passage. Thus increasing vibrations may appear up to levels (phase shifting) which can

seriously degrade the machined surface quality.

The picture below shows how chatter is formed.

Tan Yee Page 51



It is difficult to analyse and justify the perfect cutting condition by manual calculations thus

use of CAE software Cut Pro can overcome the shortcomings of human prone manual

calculation error and greatly improve the cutting condition. Cut Pro can render several cutting

inputs based on the generated stable limit diagram:

1. Cutting speed

2. Feed speed

3. Finishing cut (based on asperity to achieve)

4. Rough cut (based on machine and cutting tool maximum cutting feed and pick feed)

JTEKT High Speed Processing Technique – High speed machining has become the

standard for today’s machining as it combines the high accuracy, shorter time and lower cost

for precision industry. There are three elements to achieve high speed with high efficiency

cutting:

1. Machine – must be able to handle extreme cutting condition at the same time

maintaining the stringent machining tolerance and accuracy. Features to meet those

requirements include high rigidity spindle, high speed and high acceleration feed, high

speed and accuracy control.

2. Processing technique – Sufficient knowledge to select the correct tool and holder for

workpiece as well as technical skill to fix them up correctly.

3. CAD/CAM – Able to generate NC data for high speed cutting.

4.

Several study and research have been done to analyse and decide the best cutting condition

for milling both carbon steel (S48C) and titanium alloy (Ti6Al4V). The tool to be used will

be endmill diameter 10mm by SANDVIK Coromant codename R21624-10050-EAK22P.

Firstly, we used the radar chart to decide the cutting speed. The comparison ratio made on the

chart is used to determine the cutting speed for carbon steel and titanium alloy. Our study on

the cutting speed range for carbon steel and titanium alloy were 150-250m/min and 50-

100m/min respectively. Based on the radar chart for heat characteristic value the ratio was

3.59. We obtained cutting speed of 60 and 200 for both titanium alloy and carbon steel which

the ratio was 3.33 and this value appeared to be the nearest to the ratio on radar chart. We

have also chosen cutting stroke of 10mm and 0.05mm/tooth for feed. We then calculated

spindle speed and feed speed based on these values.

Tan Yee Page 52



Formula to calculate spindle speed and feed speed:

After calculating all the values, we came out with the following table:

no material

cutting

speed

(m/min)

cutting

stroke

(mm)

feed

(mm/

tooth)

spindle

speed

(min-1

)

feed speed

(mm/min)

cooling

channel

1 Ti6Al4V 60 10 0.05 2000 400 coolant

2 S48C 200 10 0.05 6000 1200 dry

The NC program generated by student was for one way shoulder mill utilizing down cut.

After amendment the final program was as shown below:

G91 G28 Z0

G90 G54 G00 X75.0 Y0

S1910 (titanium, or S5093 for carbon steel)

G43 Z100 H01 (H1, tool length = 150.554 mm)

M03

G01 Z5.0

Z-10.0 F382.0 (OR F1018.0)

X-5.0

G00 Z100.0

M5

G91 G28 Z0

M30

There were a lot to prepare and get ready before cutting especially on the cutter and offsetting

values. These steps could be explained as follows:

1. Measure the dimension of raw material and fix it onto the vice

2. Fix a force sensitive sensor for measuring force impact on the workpiece (not necessary

in every machining setup, only for evaluation purpose)

Spindle speed, S = V ÷ π ÷ D x 1000

V = cutting speed

π = the circular constant

D = diameter

Feed speed, F = S x f x N

S = spindle speed

f = feed per tooth

N = number of flutes

*flute = 2 based on SANDVIK

catalogue

Tan Yee Page 53



3. Check the correct dimension (diameter) of the tool

4. Check the correct tool shank used

5. Check the diameter of probe for offset and relative reference purpose

6. Fix the probe to the machine and double check the dimension of the work piece

7. Input the appropriate offset value

8. Use visual device to observe and capture the surface image of the cutter (for tool wear

inspection)

9. Remove the probe and replace with cutting tool

10. Input the tool shank height offset value in Z-direction

11. Input the NC program

12. Perform an overall dry run

13. Troubleshoot if necessary

The machine which the student used was FH550SX where ATC (automatic tool change) is

not available. Air cut is also not available on this machine thus dry cut was chosen and

coolant was used when cutting titanium alloy.

Week 4

The student started his test cut based on the cutting knowledge acquired and cutting condition

selected. The student set up the tool and zero set prior to the actual cut. By working in a team

with his supervisor Mr Ohtani, engineer Mr Toda and his partner Mr Teo Hao Yang the

cutting process was deemed to be smooth and successful. The student also helped to inspect

tool wear and all results were recorded. For details on the cutting outcome, please refer to full

report at Appendix A.

New project was assigned this week as the cutting department received cutting test asking

from Saudi Arabia. The task was to test cut on stainless cast to justify the capability of

Toyoda machine in cutting hard-to-cut alloy. If successful Saudi Arabia customers might

purchase machine from the company so this was an important project for student. It was also

the first time student involved in international industrial project. The student studied the

characteristics of the alloy

Week 5

The surface of the milled workpiece was measured to assess its surface roughness correspond

to the selected cutting conditions. This was equally important compared to the measure of

Tan Yee Page 54



tool wear after each cutting as surface finishing could be demanding to meet stringent

requirement by customer or industrial needs. To measure the asperity of the finished surface,

there are a few procedures to follow:

1. Master set the mechanical stylus with a surface master plate

2. Approach the stylus to the intended surface (ensure that the arm supporting

stylus is parallel to the surface)

3. Push the “start” button to start measuring

4. The values for Z, Ra, Ry and Rz are recorded.

5. Steps 2 to 4 are repeated for the following surface.

The illustration above shows the concept of mechanical stylus system to acquire

surface roughness data on the specimen.

For more details on the surface roughness measured and results analysis, please refer to

Surface Roughness Observation and Analysis in Appendix A.

Student also started cutting on KHR35CT based on selected cutting speed of 60, 90 and 120

m/min. The values are used for reference to calculate spindle speed and feed rate. There are

few steps to follow prior to actual cut.

1. Input NC data (program can be referred to attachment)

2. Tool is installed to the holder and the height is checked using tool presetter.

3. Tool height offset value is input to the machine.

4. Zero set the coordinates of workpiece corresponds to machine home coordinates.

Tan Yee Page 55



5. Probe is used to zero set in Z direction.

6. Dry run is simulated to check the program. (modification is made if simulated

cutting is not desired.)

7. Cutting is started by input the values of cutting stroke (Z) and diameter (J#100)

intended to cut.

8. After cut, the tool is removed for tool wear inspection.

9. Value for tool wear is recorded and observation image is saved.

10. The tool is installed into the machine for the following cut.

11. Steps 7 to 10 are repeated after every cut.

For more details on the results for KHR35CT test cut, please refer to Appendix B. The

cutting setup has been explained above so no cutting procedure was explained in the report.

The report only contained cutting results and explanation.

1 2

3

*since the outer diameter of the workpiece is rough (black area) thus the center

point of the diameter is set in reference to the inner diameter.

1. X direction is first measured to get the center point. (red)

2. Y direction is then measured based on X center point to get the center point

as well. (orange)

3. X direction is measured again based on the center point of Y. (yellow)

4. The center point of the second X measurement will be the center used to

zero set the position of the workpiece.

Tan Yee Page 56



Week 6

Student has been assigned to do a practice on CAM for cylinder block. Prior to this activity

he was given a list of formula of JTEKT from his supervisor on how to obtain the cutting

conditions (cutting speed, feed-per-tooth, spindle speed, feed rate) based on the cutting

process – roughing, semi-finishing or finishing.

The table below shows the cutting conditions he has calculated for the CAM exercise:

Extension

(mm) L/D

Cutting speed

(m/min)

Feed-per-

tooth

(mm)

Spindle speed

(rpm)

Feed rate

(mm/min)

75 2.5 350 0.15 3714 1115

75 6.25 130 0.07 3448 483

75 12.5 60 0.03 3183 191

75 6.25 130 0.07 3448 483

75 6.25 150 0.30 7958 4775

No File_name Process

Tool

Dia

(mm) Flutes Shape

1 Cavity mill Roughing 30 2 End mill

2 Corner

rough Semi-finish 12 2 Ball mill

3 Corner

rough 2 Semi-finish 6 2 Ball mill

4 Z level

profile Semi-finish 12 2 Ball mill

5 Fixed

contour Finishing 1 2 Ball mill

6 Flowcut-

vet-tool Finishing 4 2 Ball mill

Tan Yee Page 57



80 20 80 0.17 6366 2164

Offset

(mm)

Cutting Amount (mm)

Z-Axis

0.1 0.15

0.1 0.08

0.1 0.06

0.1 0.08

0 0.30

0 0.17

The formula involved in calculating cutting depth and feed-per-tooth for finishing:

Alternative values such as cutting speed and feed rate can be read from the graphs in “JTEKT

Cutting Condition Selection Guidebook”. (However graph cannot be attached here due to

confidentiality.)

Student also learnt how to do Computer Aided Manufacturing (CAM) by learning how to

calculate and input cutting parameters into data sheet prior to simulation. These cutting

conditions or parameters are very important as they will determine the best NC program to be

input in the machine for cutting. The software which the student hands-on include:

UG NX 8.0 (Unigraphics)

Vericut

Mill Plan 5 Axis

√

where:

hf: theoretical surface roughness

R: tool radius

Pf: cutting depth

f: feed-per-tooth

Tan Yee Page 58



UHPC- II (Ultra High Precision Control)

For details on CAM knowledge acquired, please refer to CAM – Computer Aided

Manufacturing.

The student has joined Kondou (an engineer in the company) san to observe how to check for

machine’s vibration. Knowing machine’s vibration is important as it might be the hidden

cause to machine inaccuracy if not known or noticed. Vibration could also be the culprit to

chatter as well. The brief procedures to setup the vibration testing unit FFT (Fast Fourier

Transform) analyzer are as follow:

1. FFT is turned on and hooked to the necessary connections (PC, transducer and

hammer)

2. The necessary software is booted

3. Transducer is attached to spindle (or workpiece, tool 1, tool 2)

4. Hammer is used to hit the spindle in X direction

5. Based on the FT graph, result is recorded for KHz, dB for vibration in X (higher

peaks on graph are selected)

6. Steps 4 to 5 are repeated for Y and Z direction

7. Steps 3 to 6 are repeated for workpiece, tool no 1 and tool no 2

After the test, research was done to understand the working principle of hammering and how

to analyze machine vibration according to Fast Fourier Transform (FFT). The FFT is a

computerized mathematical algorithm for transforming vibration signals from the time

domain (time waveform) into the frequency domain. The Fourier Transform, a plot of

vibration amplitude vs frequency, is especially useful for frequency analysis which is the

analytical method most often used for fault recognition in operational machines. Machines

can be examined during regular operation, start-up and run down or during tests and

experiments. This analysis can be performed without interrupting the normal operation of

the machine. FFT’s are helpful in diagnosing faults associated with unbalance,

misalignment, eccentric components and damaged bearings, shafts, gears or motor electrical

faults. The data is used to predict faults and impending failures. Non-linear trends (sharp

increases in vibration levels or bearing condition levels) generally are an indication of

impending problems. This warning enables the maintenance department to schedule the

necessary repairs before an unexpected failure occurs, causing downtime and lost

productivity. A trend analysis (overall vibration measurements, bearing condition

Tan Yee Page 59



measurements, FFT’s and BCS’s (bearing condition spectrums)) is implemented from time to

time (as required) following a complete initial analysis as a baseline. Reporting is easily

customized to suit the customer’s needs and may be presented either in hard copy or

electronically, or both.

Both the vibration results and graph for Fourier transform is not attached here due to

confidentiality. Examples showing a typical FFT graph and the way to analyze it will be

explained.

Understanding Time and Frequency Analysis:

Structural vibration can be measured by electronic sensors that convert vibration motion into

electrical signals. By analyzing the electrical signals, you can learn about the nature of the

vibration. Signal analysis is generally divided into time and frequency domains; each domain

provides a different view and insight into the nature of the vibration.

Time domain analysis starts by analyzing the signal as a function of time. An oscilloscope,

data acquisition device, or signal analyzer can be used to acquire the signal. In our test an

electrical signal transducer is used to check for vibration in the machine spindle, workpiece

and tool holder. The following illustration shows an example for vibration on structure (such

as a single- story building) that responds to an impact with a vibration that is measured at

point A and plotted versus time. The dashed lines indicate the motion of the structure as it

vibrates about its equilibrium point.

The plot of vibration versus time provides information that helps characterize the behavior of

the structure. It behavior can be characterized by measuring the maximum vibration (or peak)

level, or finding the period, (time between zero crossings), or estimating the decay rate (the

amount of time for the envelope to decay to near zero). These parameters are the typical

results of time domain analysis.

Tan Yee Page 60



Frequency analysis also provides valuable information about structural vibration. Any time

history signal can be transformed into the frequency domain. The most common

mathematical technique for transforming time signals into the frequency domain is called the

Fourier Transform. Fourier Transform theory says that any periodic signal can be represented

by a series of pure sine tones. Following figure shows how a square wave can be constructed

by adding up a series of sine waves; each of the sine waves has a frequency that is a multiple

of the frequency of the square wave. The amplitude and phase of each sine tone must be

carefully chosen to get just the right waveform shape.

In the figure, the third graph shows the amplitude of each of the sine tones. There are three

sine tones in the first plot, and they are represented by three peaks in the third plot. The

frequency of each tone is represented by the location of each peak on the frequency

coordinate in the horizontal axis. The amplitude of each sine tone is represented by the height

of each peak on the vertical axis. This third plot can be interpreted as the Fourier Transform

of the square wave. In structural analysis, usually time waveforms are measured and their

Fourier Transforms computed. The Fast Fourier Transform (FFT) is a computationally

Tan Yee Page 61



optimized version of the Fourier Transform. The third plot also shows the measurement of

the square wave with a signal analyzer that computes its Fast Fourier Transform.

Understanding Decibel dB Scale:

Vibration data is often displayed in a logarithmic scale called the Decibel (dB) scale. This

scale is useful because vibration levels can vary from very small to very large values. When

plotting the full data range on most scales, the small signals become virtually invisible. The

dB scale solves this problem because it compresses large numbers and expands small

numbers. A dB value can be computed from a linear value by the equation:

)

Where

Xref is a reference number that depends on the type of measurement. Comparing the motion

of a mass to the motion of the base, base measurement is used as the reference in the

denominator and the mass as the measurement in the numerator.

In the dB scale, if the numerator and denominator are equal, the level is zero dB. A level of

+6 dB means the numerator is about a factor of two times the reference value and +20 dB

means the numerator is a factor of 10 times the reference. The following two graphs show an

FFT in linear scale on the top and dB scale on the bottom. Notice that the peak near 200 Hz is

nearly indistinguishable on the linear scale, but very pronounced with the dB scale.

Tan Yee Page 62



Root Cause Analysis and Remedy:

Usually there is a standard that comes with every machine which has the permissible

vibration limits before it is deemed to be faulty and starting to give in problem. The vibration

flowchart below shows how to diagnose vibration result and appropriate corrective action or

remedy. Benign vibrations are characteristic of regular operation of a machine doing what it is

supposed to do. The amplitudes will vary from machine to machine and are a measure of the quality

of manufacturing and load condition. The presence of these benign vibrations at “normal” levels

provides a comfortable feeling that the machine is still alive. A change above normal levels not

explained by a corresponding load change is reason for investigation, but not alarm.

Tan Yee Page 63



Machine vibration has several categories of causes that are discovered sometimes after repair,

but it is useful now to review them to gain more confidence in the diagnosis. The major

categories are –

• Design defects - are mostly structural related with active resonances built-in because

of improper sizing and proportioning of the parts. Statically, the structure is alright but

is dynamically weak. This is not discovered until the machine is energized and

brought up to speed. This is more common than it should be, but designers are not

well equipped to predict or test for natural frequencies. In addition, the owners’

foundation or base has a significant effect on natural frequencies, which the designer

has little control over. Hence, resonances are best detected during startup testing and

corrected on-site with strategic stiffeners added.

• Manufacturing defects - are built-in during the casting, machining, heat-treating, and

assembly processes. They are latent defects that may show up in the first 24-hours of

running, or they may not be obvious during the run-in period, rather appearing years

later. The machine does not survive to a normal life expectancy. Vibration may or

may not be present. An example is residual stresses in a shaft that gradually distorts

the shaft over a period of years. Manufacturing defects are difficult to control,

impossible to predict, and elusive to fix. The best strategy to deal with both design

Tan Yee Page 64



defects and manufacturing defects is to insist on startup vibration testing with limits of

acceptability in accordance with standard for vibration limits.

• Operational stresses - can develop due to material buildup or erosion that changes

the balance condition, or thermal expansion that changes component alignment. Both

of these cause high dynamic loads at the bearings which lead to accelerated wear out.

These defects are easily detected with periodic vibration measurements and there are

well established methods to correct them on site.

• Aging - can only be detected with long term vibration monitoring. The two dominant

aging effects are residual stress relaxation and softening of structural joints. The

residual stresses left behind in machine components will always relieve themselves

over time. This process is accelerated at higher temperature. Shafts, being long and

slender components, are particularly vulnerable to bowing. The symptoms are an

increase in RPM (revolution per minute) balance condition and beating up of the

bearings. Bearing replacements do not restore the original smooth running condition,

and mass balancing is unsuccessful, until the shaft is replaced.

The second test cut on titanium alloy using end mill of tool diameter 80mm. The procedures

for setup were basically the same as the previous test cut on titanium except the tool which

has thus gained in size. The tool used was indexable end mill by OSG Japan. The NC data for

this cutting was:

N01

G90 G00 G54 X160. Y-150. S312

G43 Z100. H01

Z-50.

M03

M08

G01 Y-35. F125.

G01 X-50.

G00 Y-50.

G00 G90 Z100.

Variable such as

spindle speed,

cutting depth,

cutting width and

feed rate change

Tan Yee Page 65



Cutting results are currently still in process and will be shown in coming report.

Tan Yee Page 66



6. Key Challenges faced and solutions proposed

a. Technical Problems faced during attachment

The student faced a few technical difficulties when doing cutting his test projects

collaborated with the company’s core projects. These technical challenges were some minor

which could be solved with ease but some were intractable and required some time and study

to troubleshoot and solve the problems. The technical problems which the student faced were:

1. Deciding Cutting Speed for Carbon Steel and Titanium Alloy was a challenging

task for the student as the student did not have strong background in material study

thus study needed to study from several material catalogues and did online research

on the material characteristics. Value for cutting speed was the most crucial value for

the test cut as subsequent cutting parameters like spindle speed, feed rate were all

derived based on cutting speed. Incorrect or inappropriate cutting speed might result

in experiment failure.

2. The Inconsistency of Cutting Resistance recorded during the fifth cut when cutting

carbon steel. Theoretically this should not be happening as the cutting depth incurred

was far below the cutting limits. Chatter was suspected and troubleshooting was

carried out to inspect the real cause.

3. Severe Tool Wear was inspected when milling carbon steel or titanium alloy at

elevated cutting speed. Technical study was carried out to study the solution for

lowering cutting resistance that may incur and eventually improve the capability of

the machine. The aim of these findings was to provide lower cutting parameters

(cutting speed and feed speed in reference to cutting depth and width) to mill titanium

alloy which makes cutting heat resistant alloy possible on normal specs machine.

(usually high specs machine is required for cutting hard heat resistant alloy)

b. Solutions Proposed and Outcome

1. Deciding Cutting Speed for Carbon Steel and Titanium Alloy

Student utilized the “Radar Chart” knowledge acquired from the cutting lecture to

decide the cutting speed. He searched thru the internet to look for each material

technical specification before plotting out radar chart. The findings for technical

specification and description can be referred to Appendix A: Comparison of

Technical Characteristics. Important values like Vickers Hardness, extension, tensile

strength and heat characteristic value were used to plot radar chart using carbon steel

Tan Yee Page 67



as baseline and titanium to compare against it. Radar chart can be found at Appendix

A: Analysis of S48C and Ti6Al4V using Radar Chart. As cutting heat induced is

proportional to cutting speed so cutting speed for carbon steel and titanium alloy will

be based on the ratio of heat characteristic value on radar chart. Cutting speed for

S48C was selected to be 200m/min (reference). The ratio for heat characteristic value

for the two materials is 3 (please refer to radar chart below highlight in yellow).

With the cutting speed of carbon steel and heat characteristic value ratio of 3, cutting

speed for titanium will be: 200m/min / 3 = 66m/min ~ 60m/min (approximate)

*divide instead of multiply by 3 as the heat characteristic value for titanium is 3 times of

carbon steel so the cutting speed has to be lesser.

Selected cutting condition can be found at Appendix A: Cutting Condition.

2. The Inconsistency of Cutting Resistance

Theoretically speaking the cutting resistance should increase following the depth of

cut but during the test cut there was unexpected observation.

0

1

2

3

4hardness

tensilestrength

extension

heatcharacteristi

c value


S48C

Ti6Al4V

http://www.google.co.jp/url?sa=t&rct=j&q=cutting%20speed%20for%20s48c&source=web&cd=4&cad=rja&ved=0CDoQFjAD&url=http%3A%2F%2Fwww.tungaloy.co.jp%2Fcommon%2Fproducts%2Fpdf%2F354.pdf&ei=XM8dUZaaG4ualQX6s4GgAg&usg=AFQjCNGVm1jLxP_1VXy2u-j3x4HrthmjqA

Tan Yee Page 68



Appendix A

Tan Yee Page 69



Report on

Understanding the Feature of Titanium Alloy

and High Efficiency Cutting

By:

Tan Yee

Supervisor:

Mr Hisashi Ohtani

Project commenced:

14 Jan 2013

Tan Yee Page 70



Contents

Objectives: ............................................................................... Error! Bookmark not defined.

Hypothesis: .............................................................................. Error! Bookmark not defined.

Theoretical Understanding/Background: ................................. Error! Bookmark not defined.

Heat-resistant Alloy ............................................................. Error! Bookmark not defined.

S48C (Carbon Steel) ............................................................ Error! Bookmark not defined.

Ti6Al4V (Titanium Alloy) ................................................... Error! Bookmark not defined.

Comparison of Technical Characteristics: ........................... Error! Bookmark not defined.

Analysis of S48C and Ti6Al4V using Radar Chart: ............ Error! Bookmark not defined.

Surface Roughness ............................................................... Error! Bookmark not defined.

Tool Wear (Flank and Crater) .............................................. Error! Bookmark not defined.

Task: ......................................................................................... Error! Bookmark not defined.

Introduction .......................................................................... Error! Bookmark not defined.

Cutting Condition................................................................. Error! Bookmark not defined.

Cutting Test .......................................................................... Error! Bookmark not defined.

NC Data ............................................................................... Error! Bookmark not defined.

Equipments/Materials used: ................................................. Error! Bookmark not defined.

Setup .................................................................................... Error! Bookmark not defined.

Procedure ............................................................................. Error! Bookmark not defined.

Pre-Cutting ....................................................................... Error! Bookmark not defined.

Cutting.............................................................................. Error! Bookmark not defined.

Post-Cutting ..................................................................... Error! Bookmark not defined.

Cutting Results: ........................................................................ Error! Bookmark not defined.

Test Cut No 1 (Ti6Al4V condition 1) .................................. Error! Bookmark not defined.

Test Cut No 2 (S48C condition 2) ....................................... Error! Bookmark not defined.


Tan Yee Page 71




Cutting Load Analysis: ............................................................ Error! Bookmark not defined.

Graph.................................................................................... Error! Bookmark not defined.

Discussion ............................................................................ Error! Bookmark not defined.

Cutting Resistance Analysis: ................................................... Error! Bookmark not defined.

Graph (Cutting Resistance Fx) ............................................. Error! Bookmark not defined.

Discussion (Cutting Resistance Fx) ...................................... Error! Bookmark not defined.

Graph (Cutting Resistance Fy)............................................. Error! Bookmark not defined.

Discussion (Cutting Resistance Fy) ..................................... Error! Bookmark not defined.

Graph (Cutting Resistance Fz) ............................................. Error! Bookmark not defined.

Discussion (Cutting Resistance Fz) ..................................... Error! Bookmark not defined.

Surface Roughness Observation and Analysis: ....................... Error! Bookmark not defined.





Graph for Maximum Peak, Ry ............................................. Error! Bookmark not defined.

Graph for Ten Point Mean Roughness, Rz .......................... Error! Bookmark not defined.

Discussion ............................................................................ Error! Bookmark not defined.

Tool Wear Observation and Analysis: ..................................... Error! Bookmark not defined.





General Discussion .................................................................. Error! Bookmark not defined.

Conclusion ............................................................................... Error! Bookmark not defined.

Tan Yee Page 72



Objectives: 1. To study and understand the characteristics of selected heat-resistant alloy – Carbon

Steel S48C and Titanium Alloy Ti6Al4V

2. To compare and select the best cutting condition for milling heat-resistant alloy using

endmill ( 10)

Hypothesis:

1. Faster cutting speed will be used for cutting carbon steel whereas slower speed

applies to titanium alloy. This is due to the nature of the material where carbon steel

is softer and titanium alloy harder.

2. Cutting condition for carbon steel will not be appropriate for titanium alloy as this

may accelerate tool wear and induce stress on machine. The vice versa also applies.

Theoretical Understanding/Background:

Heat-resistant Alloy

Are alloys that have high creep resistance and strength at high temperature. The great heat

resistance of alloys is determined by two basic physical factors: the strength of interatomic

bonds in the alloy and the alloy’s structure.

The structure necessary for high strength is usually produced by heat treatment that leads to

heterogenization of the microstructure—most often precipitation hardening. In this case, the

strengthening is caused mainly by the appearance within the alloy of evenly distributed very

small particles of chemical compounds (intermetallides, carbides, and other compounds) and

by the microscopic distortions of the crystal lattice of the alloy base generated by the

presence of the particles. The corresponding structure of heat-resistant alloys retards the

formation and movement of dislocations and also increases the number of bonds between

atoms, which simultaneously participate in the resistance to deformation. On the other hand, a

large number of interatomic bonds makes possible the retention of the required structure for

long periods at high temperature.

Tan Yee Page 73



Heat-resistant alloys are classified according to their base, which may be nickel, iron,

titanium, beryllium, and other metals. Classification according to the base gives a

representation of the range of working temperatures, which is 0.4–0.8 of the melting point of

the base, depending on the load applied and the duration of its application.

Reference: http://encyclopedia2.thefreedictionary.com/Heat-resistant+Alloys

S48C (Carbon Steel)

Is known as mild steel, also called plain-carbon steel, is the most common form of steel

because its price is relatively low while it provides material properties that are acceptable for

many applications, more so than iron. Low carbon steel contains approximately 0.05–0.15%

carbon and mild steel contains 0.16–0.29% carbon, making it malleable and ductile. Mild

steel has a relatively low tensile strength and malleable.

Reference: http://en.wikipedia.org/wiki/Carbon_steel

Ti6Al4V (Titanium Alloy)

Also known as Ti6Al4V, Ti-6Al-4V or Ti 6-4, is the most commonly used alloy. It has a

chemical composition of 6% aluminium, 4% vanadium, 0.25% (maximum) iron, 0.2%

(maximum) oxygen, and the remainder titanium. It is significantly stronger than

commercially pure titanium while having the same stiffness and thermal properties. Among

its many advantages, it is heat treatable. This grade is an excellent combination of strength,

corrosion resistance, weld and fabricability.

Reference: http://en.wikipedia.org/wiki/Titanium_alloy

Tan Yee Page 74



Comparison of Technical Characteristics:

Ti6Al4V S48C

Composition

It has a chemical composition of 6%

aluminum, 4% vanadium, 0.25%

(maximum) iron, 0.2% (maximum)

oxygen, and the remainder titanium.

It has a chemical composition of 0.45-

0.51% carbon (maximum), 0.15-0.35% of

silicon, 0.60-0.90% of manganese, up to

0.030% of phosphorus and maximum

0.035% of sulphur. The remaining will be

iron.

Material Characteristics

Stronger than pure titanium

Good stiffness and thermal

properties

Excellent combination of strength,

corrosion resistance, weld and

fabricability

Used in application up to 400 degree

C

Density of 4420kg/m3

Young’s modulus of 110GPa

Tensile strength 1000MPa

Hardness value (Vickers hardness)

of 349

Extension at 14%

Thermal conductivity of 6.7 W/m-K


Malleable and ductile

Low tensile strength at 585 MPa

Hardness can be improved by

carburizing (heat treatment)

Density of 8000 kg/m3

Young’s modulus 210GPa

Hardness value (Vickers hardness) of

170

Extension at 12%

Thermal conductivity of 51.9 W/m-K


Cutting Characteristics

Low cutting speeds

High feed rate

Generous amount of cutting fluids

Using sharp tools

Have rigid setup

Generally soft easier to machine

Prolong tool life with increasing

cutting speed

High feed rate

Less coolant required

Over rigid setup might dent

workpiece

Tan Yee Page 75



Analysis of S48C and Ti6Al4V using Radar Chart:

Properties Ti6Al4V S48C

Hardness (Vickers hardness,

HV) 349 170

Tensile strength (MPa) 1000 585

Extension (%) 14 12

Density, ρ (kg/m3) 4420 8000

Thermal conductivity, K

(W/m-k) 6.7 51.9

Specific heat, C (J//kg.K) 0.5263 0.4860

Heat characteristic value (K

ρC)^-0.5 8.01x10

-3 2.23x10

-3

Tan Yee Page 76



Calculation was made based on the selected parameters:

Hardness : 349/170 = 2.05

Tensile strength : 1000/585 = 1.71

Extension : 14/12 = 1.17

Heat characteristic value : 8.01x10-3

/2.23x10-3

= 3.59

Radar chart was plotted based on the calculated values:

0

1

2

3

4hardness

tensile strength

extension

heatcharacteristic

value


S48C

Ti6Al4V

Cutting temperature

Cutting resistance

Tan Yee Page 77



Surface Roughness

Surface roughness, often shortened to roughness, is a measure of the texture of a surface. It is

quantified by the vertical deviations of a real surface from its ideal form. If these deviations

are large, the surface is rough; if they are small the surface is smooth. Roughness is typically

considered to be the high frequency, short wavelength component of a measured surface.

Surface metrology is the study of surface geometry, also called surface texture or surface

roughness. The approach is to measure and analyze the surface texture in order to be able to

understand how the texture is influenced by its history, (e.g., manufacture, wear, fracture) and

how it influences its behavior (e.g., adhesion, gloss, friction).

In surface metrology context, several terminologies are used to analyse the roughness

behaviour. They are mainly:

Arithmetical Mean Roughness (Ra)

A section of standard length is sampled from the mean line on the roughness chart. The mean

line is laid on a Cartesian coordinate system wherein the mean line runs in the direction of the

x-axis and magnification is the y-axis.The value obtained with the formula on the right is

expressed in micrometer (μm)when y=f(x).

Tan Yee Page 78



Maximum Peak (Ry)

A section of standard length is sampled from the mean line on the roughness chart. The

distance between the peaks and valleys of the sampled line is measured in the y direction.

The value is expressed in micrometer(µm)

Ten Point Mean Roughness

A section of standard length is sampled from the mean line on the roughness chart. The

distance between the peaks and valleys of the sampled line is measured in the y direction.

Then, the average peak is obtained among 5 tallest peaks(Yp) , as is the average valley

between 5 lowest valleys(Yv) . The sum of these two values is expressed in micrometer (µm).

Tan Yee Page 79



Reference: http://en.wikipedia.org/wiki/Surface_roughness

http://www.phase2plus.com/surfaceroughnesstesters/profile-parameters.htm

Tool Wear (Flank and Crater)

Tool wear describes the gradual failure of cutting tools due to regular operation. It is a term

often associated with tipped tools, tool bits, or drill bits that are used with machine tools.

Types of wear include:

Flank wear in which the portion of the tool in contact with the finished part erodes.

Can be described using the Tool Life Expectancy equation.

Crater wear in which contact with chips erodes the rake face. This is somewhat

normal for tool wear, and does not seriously degrade the use of a tool until it becomes

serious enough to cause a cutting edge failure.

Reference: http://en.wikipedia.org/wiki/Tool_wear

Tan Yee Page 80



Task:

Introduction

The intern task was to test cut two workpieces of different materials – mild carbon steel

codename S48C and titanium alloy codename Ti6Al4V. Intern has to calculate and select the

best cutting condition for the two different materials based on the characteristic of tool and

capability of machine.

Cutting Condition

After doing study from SANDVIK catalogue and internet, supervisor and intern have decided

to choose 60 and 200 as cutting speed (m/min) for Ti6Al4V and S48C respectively. Cutting

stroke was set to be 10mm whereas feed per tooth was 0.05mm. The intern calculated spindle

speed and feed rate based on formula shown below:

After calculation and finalisation, cutting condition is as shown in the table below:

no material

cutting

speed

(m/min)

cutting

stroke

(mm)

feed

(mm/

tooth)

spindle

speed

(min-1

)

feed speed

(mm/min)

cooling

medium

Ti6Al4V 60 10 0.05 1910 382

coolant

S48C 200 10 0.05 6366 1273 dry

Feed speed, F = S x f x N

S = spindle speed

f = feed per tooth

N = number of flutes

*flute = 2 based on SANDVIK

catalogue

Spindle speed, S = V ÷ π ÷ D x 1000

V = cutting speed

π = the circular constant

D = diameter

Tan Yee Page 81



Cutting Test

NC Data

For condition For condition

G91 G28 Z0

M11

G54 G90 G00 B0

M10

G90 G54 G00 X75.0 Y-5.0

S1910

G43 Z100.0 H01

M3

G00 Z5.0

G01 Z-10.0 F382.0

X-5.0

G00 Z100.0

M5

M9

G91 G28 Z0

M30

G91 G28 Z0

M11

G54 G90 G00 B0

M10

G90 G54 G00 X75.0 Y-5.0

S5093

G43 Z100.0 H01

M3

M8

G00 Z5.0

G01 Z-10.0 F1018

X-5.0

G00 Z100.0

M5

M9

G91 G28 Z0

M30

*Highlight shows where the difference is. (M8 stands for coolant on)

Test No Material Cutting Condition

1 Ti6Al4V

2 S48C

3 Ti6Al4V

4 S48C

Tan Yee Page 82



*For condition , spindle speed and feedrate are reduced to 80% of the original calculation

due to machine limitation.

Equipments/Materials used:

Machine model : FH550SX Horizontal Machining Center

Work material : S48C, Ti6Al4V (100 x 100mm)

Metrology needs : Dial indicator (flatness and roundness), digital microscope (OMRON

Vision for tool wear inspection), tool presetter (tool height, probe

height)

Tool Changer : BIG tool shank holder and nut tightener/releaser

Detector : Force sensitive sensor consists of amplifier, a graph visualizer, and

PC loaded with FANUC SERVO GUIDE

Coordination : Probe

Setup

Holder

Work material

(Ti6Al4V, S48C) Vice

Cutting power

gauge

Locating angle plate

test jig

Tool Spindle

Tan Yee Page 83



Procedure

Pre-Cutting

1. The selected cutter of diameter 10mm is installed into the tool shank with the aid of

holder and nut tightener/releaser. The shank is first put into the holder then is loosen by

releaser (followed anti-clockwise rotation) to install the cutter. The cutter can only

protrude out 3cm from the locking flat surface (a ruler is used for this measurement).

2. The height of the tool and probe is measured using tool presetter. The tool presetter is

master set prior to measurement using master tool of height 150.055mm. After master

set, the height of the tool is inserted to measure its height. The value is recorded for tool

length offset value for the machine later.

3. The values for the length of probe is recorded using the same tool presetter..

4. Workpiece is fixed on to the fixture.

5. Dial indicator is used to determine the flatness of the workpiece. Two flatness values are

obtained. First in X direction and then in Y direction.

Tan Yee Page 84



6. If the flatness is out of tolerance (>0.1µm), corrective action is taken (do a rough face

mill to get a parallel surface).

7. Cutter is fixed into the chuck and the roundness is checked using dial indicator. Dial

indicator is fixed to the flat surface of vice with magnetic induced base. The probe is

then approached to touch and check the highest point on the flute of the cutter. This is

done by rotating the tool shank to check for the highest point. The difference in the

highest and lowest points of the rotating flutes is calculated.

8. If roundness value is off tolerance (>0.1µm), contact points for installing the cutter into

the chuck will be reversed.

9. Coordinate position of the machine relative to the workpiece is checked using probe.

Probe is brought to approach the right side of the workpiece in X direction. The value is

then recorded. The probe is retracted and brought the bottom side of the workpiece in Y

direction. The probe is then approaching and touching the surface until a red light is

seen. Relative value is recorded. Both X and Y values are recorded and minus of 3mm

(to compensate the radius of probe of diameter 6mm).

10. Offset values and tool height value are input into the NC system accordingly.

11. Force sensitive sensing system is set up.

Cutting

12. NC program is input and a dry run is performed.

13. Necessary adjustment is made if the result of dry run is not up to satisfaction. (if the

cutting path is not what we wanted, NC program is revised)

14. Y value is set accordingly to the intended cut depth.

15. Workpiece is cut (feedrate is set to 100%).

16. Tool is removed after cutting and sent for inspection.

17. Graph on the sensing unit is analysed and all necessary info and values are recorded.

Tan Yee Page 85



Post-Cutting

18. Tool is inspected using digital microscope.

19. Inspected values for tool wear on flank and crater are recorded.

20. Snapshots for both the flank and crater are saved for further analysis.

21. Workpiece is also checked for surface roughness and values for Z, Ra, Ry and Rz are

recorded.

*Steps 1 to 13 are repeated after changing to another new cutting condition:

a) Cutting Ti6Al4V using cutting condition

b) Cutting S48C using cutting condition

c) Cutting Ti6Al4V using cutting condition

d) Cutting S48C using cutting condition

*Steps 14 to 21 are repeated following every incremental made after the previous cut of the

same cutting condition.

Tan Yee Page 86



Cutting Results:

Test Cut No 1 (Ti6Al4V condition 1)

Test Cut No 2 (S48C condition 2)

Material Cutting

No

Cutting

Depth, Ae

(mm)

Cutting

Load

(%)

Cutting Resistance (N)

Fx Fy Fz

Titanium

Alloy

(Ti6Al4V)

1 0.1 0.1 85.8 78.6 35.8

2 0.5 0.3 171.4 185.8 92.8

3 1.0 0.7 271.4 307.2 150.0

4 2.0 1.4 342.8 492.8 242.8

5 3.0 2.0 371.4 657.2 328.6

6 4.0 2.7 378.6 807.2 421.4

7 5.0 3.2 350.0 942.8 507.2

8 6.0 4.1 328.6 1092.8 600.0

9 7.0 4.7 250.0 1200.0 685.8

10 8.0 5.5 385.8 1342.8 764.2

11 9.0 5.9 542.8 1564.2 942.8

Material Cutting

No

Cutting

Depth, Ae

(mm)

Cutting

Load

(%)


Fx Fy Fz

Carbon steel

(S48C)

1 0.1 0.3 100.0 50.0 39.4

2 0.5 1.1 203.6 125.0 107.1

3 1.0 2.1 307.0 196.4 125.0

4 2.0 5.8 371.4 507.2 271.4

5 3.0 Chatter was suspected. However it was later been

diagnosed as human error, values were suspended.

6 4.0 7.8 407.2 685.8 285.8

7 5.0 10.1 357.2 814.2 321.4

8 6.0 11.8 314.2 1000.0 428.6

9 7.0 13.8 235.8 1150.0 521.4

10 8.0 15.7 242.8 1264.2 564.2

11 9.0 17.5 421.4 1350.0 635.8

Tan Yee Page 87





Material Cutting

No

Cutting

Depth, Ae

(mm)

Cutting

Load

(%)


Fx Fy Fz

Titanium

Alloy

(Ti6Al4V)

1 0.1 0.5 67.8 60.8 57.2

Tool was severely worn and torn at first cut so no further relevant value is

recorded. Further explanation is made at “Discussion”.

Material Cutting

No

Cutting

Depth, Ae

(mm)

Cutting

Load

(%)


Fx Fy Fz

Carbon steel

(S48C)

1 0.1 0.1 125.0 75.0 42.8

2 0.5 0.4 250.0 196.4 82.2

3 1.0 0.8 428.6 350.0 114.2

4 2.0 1.6 521.4 557.2 185.8

5 3.0 2.4 521.4 742.8 235.8

6 4.0 3.1 542.8 942.8 300.0

7 5.0 3.9 528.6 1100.0 342.8

8 6.0 4.7 442.8 1200.0 371.4

9 7.0 5.4 328.6 1328.6 428.6

10 8.0 6.2 300.0 1442.8 471.4

11 9.0 7.0 342.8 1485.8 542.8

Tan Yee Page 88



Cutting Load Analysis:

Graph

Discussion

The cutting load of titanium alloy in test cut 1 increases over length and this is explainable as

more flutes are engaged with increasing cutting length. In other word, the radial depth of cut

is increased. It is the depth of the tool along its radius in the workpiece as it makes a cut. If

the radial depth of cut is less than the tool radius, the tool is only partially engaged and is

making a peripheral cut. If the radial depth of cut is equal to the tool diameter, the cutting tool

is fully engaged and thus cutting load is fully transferred to the workpiece (considering no

loss of energy).

For test cut 2 which is cutting carbon steel at higher feedrate, more cutting load is needed

compared to other test cuts. When feedrate is increased, the instantaneous chip thickness is

increased, and forces are increased. Radial and axial depths of cut affect the width and length

of the contact area, respectively. That is, when the radial and axial depth of cut are increased,

the contact area is increased, and the forces become larger. An abnormal drop in cutting load

0

2

4

6

8

10

12

14

16

18

20

0.1 0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Cutting Load, %

Length of Cut, mm

Comparison of Relationship between Length of Cut and Cutting Load for 4 Cutting Test

Test Cut 1

Test Cut 2

Test Cut 3

Test Cut 4

Tan Yee Page 89



is observed at cutting length of 3mm, this is predictable as human error was occurred at the

point of cutting where the feedrate was accidentally adjusted to slower rate.

Severe tool wear is observed at both the flank and crater for test cut 3 after the first cut.

Despite the length of cut of just 0.1mm but the cutting load needed correspond to the other 3

test cuts for the same length is the highest which is 0.5% compared to 0.1%, 0.3% and 0.1%

for test cut 1, 2 and 4. Based on the radar chart plotted earlier the hardness ratio of titanium

alloy is 2 times than of carbon steel. Thus cutting load under the same cutting condition and

length should see a hike in cutting load of about the same ratio. If we do theoretical

calculation based on the same cutting condition on cutting carbon steel which shows a cutting

load of 0.3%, the cutting load for titanium should be 0.6% (0.3% x 2). However from the test

result obtained it is 0.5%. The 0.1% difference might be due to energy and heat loss when the

load is transferred from the spindling spindle to the sensing unit.

Slightly more cutting load is needed to cut carbon steel using the titanium alloy condition. As

carbon steel is a softer material by applying a slower cutting speed of titanium alloy more

drag and friction resistance are encountered and this explain the graph of test cut 4 when

compared to test cut 1. If compare test cut 4 with test cut 2 which are both same cutting

carbon steel but under different cutting conditions, graph 4 shows a smaller cutting load

because the lower cutting speed and feedrate is directly proportional to the cutting load.

Tan Yee Page 90



Cutting Resistance Analysis:

Graph (Cutting Resistance Fx)

Discussion (Cutting Resistance Fx)

A common trend can be seen from the graph above which is the graph started to go

downwards from cutting length 4mm and eventually bounce up again from 7mm onwards. At

cutting length of 5mm it is believed that two teeth of the cutter (because cutter diameter is

10mm) are engaged with the workpiece at the instantaneous cut. Assuming that the cutter

moves in one direction, two teeth will engage the workpiece perpendicular to each other. By

resolving the cutting force into X and Y directions, we can see that both X directions cut in at

opposite directions thus offsetting each other resulting in lower cutting resistance. Refer to

the illustration below

0.00

100.00

200.00

300.00

400.00

500.00

600.00

0.1 0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Cutting Resistance Fx ,

N

Depth of Cut, mm

Comparison of Relationship between Depth of Cut and Cutting Resistance Fx

for 4 Cutting Test

Test Cut 1

Test Cut 2

Test Cut 3

Test Cut 4

Tan Yee Page 91



The illustration on the right shows when cutting depth is equal or less than 4, one tooth is

engaged and thus the cutting resistance in X direction will be the resultant cutting resistance.

When cutting depth is equal or more than 5, two teeth are engaged and resulting in two

opposite cutting resistance in X direction which will then offset each other resulting in

smaller cutting resistance.

From cutting length of 7mm onwards, at least 3 teeth are expected to engage during

instantaneous cut so the offsetting value is thus smaller resulting in bigger cutting resistance.

Cutting

depth

≤ 4

Cutting

direction

Fx1

Cutting

depth

≥5

Cutting

direction

Fx1

Fx2

+Fx1 - Fx2 < Fx1

Tan Yee Page 92



Graph (Cutting Resistance Fy)

Discussion (Cutting Resistance Fy)

Cutting resistance for direction y is predictable as it shows an upward trend following the

increase in cutting depth. As cutting depth increases, the resistance also increments as more

force is required to overcome the chip off for workpiece.

0.0

200.0

400.0

600.0

800.0

1000.0

1200.0

1400.0

1600.0

1800.0

0.1 0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Cutting Resistance Fy ,

N

Depth of Cut, mm

Comparison of Relationship between Depth of Cut and Cutting Resistance Fy

for 4 Cutting Test

Test Cut 1

Test Cut 2

Test Cut 3

Test Cut 4

Tan Yee Page 93



Graph (Cutting Resistance Fz)

Discussion (Cutting Resistance Fz)

The upward trend of this graph is also quite predictable as the work table will move in –Z

direction towards the cutter as depth of cut increases. This phenomenon is explainable as

what happened in graph Fy where cutting resistance follows the depth of cut.

0.00

100.00

200.00

300.00

400.00

500.00

600.00

700.00

800.00

900.00

1000.00

0.1 0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Cutting Resistance Fz ,

N

Depth of Cut, mm

Comparison of Relationship between Depth of Cut and Cutting Resistance Fz

for 4 Cutting Test

Test Cut 1

Test Cut 2

Test Cut 3

Test Cut 4

Tan Yee Page 94



Surface Roughness Observation and Analysis:


Material Cutting

Length, mm

Surface Roughness Value, μm

Z Ra Ry Rz

Titanium Alloy

(Ti6Al4V)

3.0 -43.6 3.03 2.37 0.63

4.0 -42.6 2.74 2.18 0.55

5.0 -42.2 1.94 1.55 0.34

6.0 -47 2.63 1.89 0.44

7.0 -43.2 1.72 0.36 2.36

8.0 -47.3 2.24 0.6 3.26

9.0 -88.7 22.1 18.4 5.1


Material Cutting

Length, mm


Z Ra Ry Rz

Carbon Steel

(S48C)

3.0 -61.9 2.31 1.68 0.35

4.0 -59 2.33 1.72 0.31

5.0 -58.4 2.95 2.1 0.39

6.0 -59.3 2.62 2.01 0.42

7.0 -61.1 4.32 2.76 0.66

8.0 -59.4 3.56 2.27 0.51

9.0 -62.7 8.1 6.6 1.6


Material Cutting

Length, mm


Z Ra Ry Rz

Titanium Alloy

(Ti6Al4V) 3.0 -97.2 1.4 1.0 0.3


Material Cutting

Length, mm


Z Ra Ry Rz

Carbon Steel

(S48C)

3.0 -62.2 2.36 1.89 0.44

4.0 -60.8 2.93 2.09 0.42

5.0 -60.4 6.97 5.43 0.94

6.0 -61.7 3.57 2.53 0.62

7.0 -62.1 4.8 3.25 0.81

8.0 -61.1 4.77 2.78 0.66

9.0 -78.3 3.2 2.4 0.6

Tan Yee Page 95



Graph for Maximum Peak, Ry

Graph for Ten Point Mean Roughness, Rz

0

2

4

6

8

10

12

14

16

18

20

3 4 5 6 7 8 9

Surface Roughness,

Ry, μm

Length of Cut, mm

Comparison of Relationship between Length of Cut and Maximum Peak, Ry

for 4 Cutting Test

Test Cut 1

Test Cut 2

Test Cut 3

Test Cut 4

0

1

2

3

4

5

6

3 4 5 6 7 8 9

Ten Point Mean Roughness,

Rz, μm

Length of Cut, mm

Comparison of Relationship between Length of Cut and Ten Point Mean Roughness,

Rz for 4 Cutting Test

Test Cut 1

Test Cut 2

Test Cut 3

Test Cut 4

Tan Yee Page 96



Discussion

Titanium alloy under cutting condition 1 for test cut 1 has the roughest surface among all

tests. The hard to cut nature of titanium alloy has contributed to this poor finish as more drag

and friction are expected during the milling operation. This surface can be further improved

by using a harder tool, machine of better stability or input the full calculated spindle speed

and feedrate for cutting (only 80% of the spindle speed and feedrate are used in this test cut

due to machine limitations).

For test cut 2 it has better surface finishing than test cut 1 as higher spindle speed and

feedrate were used to mill the workpiece. The workpiece, carbon steel is also softer than

titanium alloy which makes it easier to cut thus drag and friction are less expected. The ideal

cutting condition combined with the soft nature allows the cutting to leave a better finishing.

Test cut 3 is omitted in this discussion as only one cut is made due to tool wear.

Surface finishing for test cut 4 has the best surface finishing. This is mainly due the use of

coolant which largely reduced the heat imposed during cutting. Reduced heat leads to

decrease in drag and friction marks which play a role in affecting surface roughness.

According to the radar chart, heat characteristic value of carbon steel is 3.5 times lesser than

that of titanium alloy. Despite the lower cutting speed of titanium alloy is used to cut carbon

steel, the effect of heat on surface roughness is insignificant.

Tan Yee Page 97



Tool Wear Observation and Analysis:


Titanium Alloy (Ti6Al4V)

No. Of Cut Flank Crater

1

(0.1)

Tool wear is measured at 11.668µm.

2

(0.5)


3

(1.0)


Tan Yee Page 98



4

(2.0)


5

(3.0)


6

(4.0)


7

(5.0)


Tan Yee Page 99



8

(6.0)


9

(7.0)


10

(8.0)


11

(9.0)


Tan Yee Page 100



From the graph we can see that the initial tool wear is predictable however as the length of

cut increase the tool wear accelerates more than predicted. The tool wear reaches its peak at

cutting length of 2mm and accelerates gradually to the pint of 6mm before it starts to fall

again. The sudden jump on the point 2mm can be concluded due by observation error.

However for the length of 0.5 to 5mm the tool wear values seems to increase instead of

staying stable throughout as predicted. Theoretical expectation is overthrown in this case as

tool wear is significantly observed although at slower rate. From the image captured starting

from cutting length of 1mm, small cutting edge fractures or known as frittering is seen at the

crater side of the tool. These fractures can be due by the aluminium content in the titanium

alloy which melts and quickly form BUE (built-up edge) along the rake of cutting tools. As

the cutting length goes on, the fractures become more significant. The cutting wear at the end

of cutting is lower than the expected values thus the selected cutting condition is permissible.

0

10

20

30

40

50

60

70

80

90

0.1 0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Tool wear, µm

Lengh of Cut, mm

Reltionship between length of cut and tool wear (S48C condition 2)

Inpectedvalues

Theoreticalexpectation

Tan Yee Page 101




Carbon Steel (S48C)


1

(0.1)

Tool wear is hardly noticeable.

2

(0.5)


3

(1.0) Tool wear was not inspected due to human error.

4

(2.0)


Tan Yee Page 102



5

(3.0)


6

(4.0)


7

(5.0)


Tan Yee Page 103



8

(6.0)


9

(7.0)


10

(8.0)


11

(9.0)


Tan Yee Page 104



Based on the graph, it is observable that there are some discrepancies in both inspected and

theoretical values. The tool was mildly damaged initially which was hardly noticeable under

the inspection of digital microscope. The tool wear remained insignificant throughout the

cutting length of up to 4mm before a drastic increase in tool wear is observed. It is believed

that 4mm is the maximum cutting stress the tool can take before it hit its fatigue point. It is

seen that for cutting length beyond 4mm (starting from 5mm), the tool wear accelerates

exponentially. However at point 7 and 9mm, the tool wear values are plotting lower than

usual. This phenomenon maybe due to the different contact point during tool wear

measurement as the eye level may not fall on the same flute. As long as the discrepancies are

kept to minimal we can accept the earlier assumption as the severity of tool wear on the tool

is different from point to point. The microscopic observation shows that the damage to the

cutting tool is within acceptable level as no significant tool wear is observed except minor

thermal crack and burned mark. Application of dry cut without the use of coolant might be

the culprit contributes to excessive heat and friction which eventually lead to the cracks and

marks. Generally the cutting condition selected is satisfied as the final tool wear is lower than

predicted.

0

10

20

30

40

50

60

70

80

0.1 0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Tool wear, µm

Lengh of Cut, mm


Inpectedvalues


Tan Yee Page 105




Tool is severely worn off at first cut as the cutting condition exceeds the maximum stress that

the tool could take to cut hard titanium alloy. No further data is collected for comparison.


Carbon Steel (S48C)


1

(0.1)


2

(0.5)


3

(1.0)


Tan Yee Page 106



4

(2.0)


5

(3.0)


6

(4.0)


7

(5.0)


Tan Yee Page 107



8

(6.0)


9

(7.0)


10

(8.0)


11

(9.0)


Tan Yee Page 108



This graph shows the most abnormal trend we have obtained throughout this cutting test. The

initial cut shows a significant tool wear impact however the condition is soothed for cutting

length from 1 to 3mm before the values eventually climbing up. This situation can be

explained by the low cutting speed of titanium condition and adequate amount of coolant

being used to cut steel which the tool bears much lower stress than it could take. The damage

is thus smaller contributing to minimal tool wear. However at cutting point of 0.5mm, there is

an obvious chipping on the tool flank inspection. (Refer to the second flank wear picture

above) As S48C is a low grade of carbon steel which has sticky nature the low cutting speed

enable the chip to adhere to the tool and eventually chip off during the next cut thus forming

chipping fracture. BUE (built-up edge) is also the suspect for this cause. For the extending

cutting length after 4mm tool wear experiencing intermittent up and down on the graph. It is

understandable that the cutting condition is far way below the recommended cutting speed for

cutting carbon steel thus the more severe cutting damage at cutting length of 6 and 9mm

might be caused by the chipping on the measured tool flank. For the rest of cutting length

which a steady increase is observed in tool wear is explainable with the increase in cutting

depth. However the final tool wear is lower than predicted so the cutting condition is more

than ideal for cutting carbon steel. However the use of lower speed and coolant for cutting

0

10

20

30

40

50

60

0.1 0.5 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0

Tool wear, µm

Lengh of Cut, mm


Inpectedvalues


Tan Yee Page 109



low grade steel may appear to be wastage as economic justification is crucial especially in

commercial cutting where profit and delivery time to the customers are two main concerns.

Tan Yee Page 110



General Discussion

All the cutting results aligned quite in line with the radar chart made prior to the test cut. The

hardness value which Ti6Al4V is 2 times harder than S48C is proven by the results of cutting

load in percentage. For example under the cutting condition 2 for cutting Ti6Al4V and S48C,

the cutting load recorded is 0.5% and 0.3% respectively. The ratio is 1.7 instead of the

theoretical 2. The difference in 0.3 could be the loss of energy in the form of heat or friction

during the milling operation. Although the ratio might deviate more when compared on other

cutting length or different cutting condition as the loss of energy is difficult to justify along

the operation. However the results always show a higher cutting load when cutting Ti6Al4V

than of S48C which prove the former a harder material. Assumption made in radar chart is

accepted.

Heat characteristic value for Ti6Al4V is about 3.5 times higher than that of S48C. From this

data it is understandable that the cutting speed should maintain within the range of this ratio

to allow the best attainable cutting condition. Cutting speed for Ti6Al4V is 200m/min

whereas S48C 60m/min which conclude a ratio of 3.3. Spindle speed and feedrate are based

on these values. The tool wear for both workpieces under their optimal cutting condition

(condition 1 for Ti6Al4V; condition 2 for S48C) are way below the expected damage. These

results are encouraging as it has proven the ratio on radar chart for heat characteristic value to

be true.

0

1

2

3

4hardness

tensile strength

extension

heatcharacteristic

value


S48C

Ti6Al4V

Cutting temperature

Cutting resistance

Tan Yee Page 111



However when we swapped the cutting conditions over, results achieved are not desired.

Accelerated tool wear is seen on the tool when using faster steel cutting speed to mill

titanium. Although cutting condition of titanium could mill carbon steel, but slower spindle

speed and feedrate may cause excess drag and friction which result a rougher finishing.

Slower spindle speed and feedrate also mean a longer duration to complete the milling

operation. In today high precision industry where shorter delivery time to customer is crucial,

inappropriate slower cutting condition should be avoid.

One interesting occurrence that happened during the test cut was the cutting resistance in Fx

direction seems to be decreased at cutting depth ranging from 4-7mm. It is investigated that

when two teeth are engaged during the process of cutting the cutting resistance in X-direction

offset each other resulting a smaller cutting resistance. However the cutting resistance

regained its momentum after more teeth are engaged with increasing cutting depth close to

diameter of the tool size.

Overall cutting results meet my expectation in hypothesis and arguments established to be

valid. From this test cut I have learnt that selecting the correct cutting conditions are very

important to produce a good milling product to the extent of prolonged tool life and better

surface finishing.

Conclusion

Test cuts are important in evaluate and selecting the best cutting condition for milling prior to

mass production. Collection of data must be handled with attention as any human error

incurred during the process might jeopardize the analysis work resulting in incorrect or

insufficient data to analyse. In selecting cutting conditions, we must be highly aware of the

characteristic of the material which we want to cut. Better understanding and gauging of

material nature can be done by plotting radar chart. Technical data provided by the tool

manufacturer must be taken into account when considering cutting parameter as it will highly

affect the post cutting results such as surface finishing and tool wear itself.

In short, a very clear understanding of the going-to-cut workpiece and technical data of the

tool and machine are very important as they play a deciding factor whether the cutting

operation will be successful or not. Calculating data like spindle speed and feedrate based on

those data and setting up of machine are equally important and should not be neglected.

Tan Yee Page 112



End Of Report

Tan Yee Page 113



Appendix B

Tan Yee Page 114



Milling Report on

Kubota KHR35CT, KHR45A, KHR35CT-HiSi

(Saudi Arabia project)

By:

Tan Yee

Supervisor:

Mr Hisashi Ohtani

Project commenced:

31 January 2013

Tan Yee Page 115



Contents

Task ........................................................................................................................................ 116

Material Analysis ................................................................................................................... 116

KHR35CT .......................................................................................................................... 116

Material Characteristic Table ................................................................................................. 116

Radar Chart ............................................................................................................................ 118

Cutting Condition................................................................................................................... 121

NC Data ................................................................................................................................. 122

Cutting Results for KHR35CT............................................................................................... 123

Discussion: ......................................................................................................................... 124

Tool Wear for KHR35CT ...................................................................................................... 125

Discussion: ......................................................................................................................... 131

Tan Yee Page 116



Task

To mill stainless steel cast (KHR35CT, KHR35CT-HiSi, KHR45A) using different cutting

speed of 60, 90 and 120m/min.

Material Analysis

KHR35CT

KHR35CT is a microalloyed modification of KHR35C alloyan austentic cast stainless steel.

The addition of titanium results in the highest creep- rupture strength in the Kubota family of

modified HP alloys. It is primarily used in reformer furnaces where it's high strength can be

used to reduce wall thickness and tube weight and increase catalyst capacity. an Austenitic

cast stainless steel, including information regarding Creep, Tensile, Elastic, Density or

mass, Thermal, Chemical composition, Welding or joining.

Material Characteristic Table

S45C KHR45A

KHR45A

(800°C) KHR35CT

Hardness (Vickers Hardness,

HV) 200 200 200 190

Tensile Strength (MPa) 600 550 300 530

Extension (%) 20 11 27 12

Heat characteristic value

(KρC)^-0.5 7.61E-05 9.88E-05 6.17E-05 0.0001

Material

Characteristic

s

Tan Yee Page 117



Density, ρ (kg/m^3) 7840 8220 8220 7930

Thermal Conductivity, K

(W/m-K) 45 10.46 64 10.544

Specific Heat, C (J/kg.K) 490 460 499 460

Ratio in comparison to S45C

Hardness (HV) 1 1.00 1.00 0.95

Tensile Strength (MPa) 1 0.92 0.50 0.88

Extension (%) 1 0.55 1.35 0.60

Heat Characteristic Value

(KρC)^-0.5 1 1.30 0.81 1.31

Tan Yee Page 118



KHR35CT-

HiSi

Ti6Al4V SUS304

Hardness (Vickers Hardness,

HV) 190 320 160

Tensile Strength (MPa) 535 957 635

Extension (%) 12 10.1 58

Heat characteristic value

(KρC)^-0.5 0.000100541 0.000241 0.000126

Density, ρ (kg/m^3) 7930 4430 7920

Thermal Conductivity, K

(W/m-K) 10.46 7.5 16

Specific Heat, C (J/kg.K) 460 520 499

Ratio in comparison to S45C

Hardness (HV) 0.95 1.60 0.80

Tensile Strength (MPa) 0.89 1.60 1.06

Extension (%) 0.60 0.51 2.90

Heat Characteristic Value

(KρC)^-0.5 1.32 3.17 1.66

Characteristic

s

Material

Tan Yee Page 119



Radar Chart

0

0.5

1

1.5

Hardness(Vickers

Hardness, HV)

Tensile Strength(MPa)

Extension (%)

Heat characteristic

value (KρC)^-0.5

KHR45A

S45C

KHR45A

0

0.5

1

1.5

Hardness(Vickers

Hardness, HV)

TensileStrength

(MPa)

Extension (%)

Heat characteristic value (KρC)^-

0.5

KHR45A (800(°C)

S45C

KHR45A (800°C)

Tan Yee Page 120



0

0.5

1

1.5

Hardness(Vickers

Hardness, HV)


Extension (%)


0.5

KHR35CT

S45C

KHR35CT

0

0.5

1

1.5

Hardness(Vickers

Hardness, HV)

TensileStrength

(MPa)

Extension (%)


0.5

KHR35CT-HiSi

S45C

KHR35CT-HiSi

00.5

11.5

22.5

33.5

Hardness(Vickers

Hardness, HV)


Extension (%)

Heat characteristic

value (KρC)^-0.5

Ti6Al4V

S45C

Ti6Al4V

Tan Yee Page 121



Cutting Condition

00.5

11.5

22.5

3

Hardness(Vickers

Hardness, HV)


Extension (%)

Heat characteristic

value (KρC)^-0.5

S45C

SUS304

no material

cutting

speed

(m/min)

cutting

stroke

(mm)

feed

(mm/

tooth)

spindle

speed

(min-1

)

feed speed

(mm/min)

cooling

medium

KHR35CT 60 10 0.05 1910 382

coolant

KHR35CT 90 10 0.05 2865 573 coolant

KHR35CT 120 10 0.05 3820 764 coolant

Tan Yee Page 122



NC Data

N01 (ENDMILL10)

G90 G00 G54 X-30 Y70 S1910

G43 Z100 H01

Z-10.0

M03

M08

G01 G41 Y#100 D01 F382

G01 X0

G02 J#100

G01 X30

G40 G00 X70 M05 M09

G00 G90 Z100

G53 G00 G90 Y-530 X-350

M30

Spindle speed and

feedrate are changed

after every cutting

condition.

Cutting stroke in Z-

direction is decreased by

10mm for subsequent cut

condition.

The cutting diameter in y

axis. Value is decreased

by 2mm after every cut

of same condition.

Tan Yee Page 123



Cutting Results for KHR35CT

Cutting

speed

(m/min)

Cutting

No

Cutting

Depth

(mm)

Cutting Resistance (N) Tool

wear

(µm)

Fx

(90°)

Fx

(270°)

Fy

(180°)

Fy

(360°) Fz

60

1 2 814.2 1028.6 828.6 771.4 400.0 22.329

2 2 971.4 1042.8 885.8 900.0 314.2 44.540

3 2 971.4 1057.2 900.0 871.4 285.8 48.051

4 2 1014.2 1100.0 928.6 900.0 285.8 50.720

5 2 1028.6 1128.6 942.8 900.0 300.0 52.830

90

6 2 614.2 757.2 957.2 900.0 442.8 56.340

7 2 671.4 700.0 942.8 914.2 342.8 58.561

8 2 671.4 728.6 957.2 957.2 271.4 59.602

9 2 728.6 742.8 1000.0 957.2 300.0 65.227

10 2 742.8 757.2 1028.6 1000.0 300.0 67.799

120

11 2 685.8 785.8 842.8 785.8 442.8 51.839

12 2 757.2 771.4 914.2 957.2 300.0 53.812

13 2 771.4 785.8 957.2 971.4 228.6 120.215

14 2 885.8 871.4 1000.0 1057.2 300.0 106.719

15 2 928.6 942.8 1071.4 1085.8 328.6 132.084

Tan Yee Page 124



Discussion:

From the three plots we can see that the cutting resistance increases when the cutting speed is

decreasing. It is clear that at higher cutting speed the spindle throttles more force to overcome

the cutting resistance. The higher spindle force will thus offset the resistance resulting in

smaller values. This explanation is also valid for cutting resistance in direction Y and Z as

well.

0

200

400

600

800

1000

1200

1 2 3 4 5

Cutting resistance X, N

No of cut (each cut rep. 2mm)

Relationship between Cutting Resistance in X (90°)

to No. of Cut

60

90

120

Cutting speed, m/min

Tan Yee Page 125



Tool Wear for KHR35CT

Cutting speed: 60m/min

No of cut Flank Observation Crater Observation

1

2

3

Tan Yee Page 126



4

5

5

(4 x

magnification)


Tan Yee Page 127



1

2

3

4

Tan Yee Page 128



5

5

(4 x

magnification)


1

Tan Yee Page 129



2

3

4

5

Tan Yee Page 130



5

(4 x

magnification)

Tan Yee Page 131



Discussion:

Tool wear accelerated at elevated cutting speed. This is reasonable as the cutting speed

increases friction and heat drag are expected to be more intense resulting in more severe tool

wear. However at cutting speed of 120m/min for cutting distance of 8mm, there is slight drop

on tool wear. It is believed that this phenomenon is caused by the measuring error made.

Theoretically the tool wear should be increase exponentially to the length of cutting distance.

0

20

40

60

80

100

120

140

2 4 6 8 10

Tool Wear, µm

Cummulative Cutting Distance, mm

Comparison of Tool Wear under different Cutting Speed

60

90

120

Cutting speed, m/min

Date post:	14-Apr-2017
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