UNIVERSITI TEKNIKAL MALAYSIA MELAKA

APPLICATION OF TAGUCHI METHOD IN THE

OPTIMIZATION OF CUTTING PARAMETER FOR SURFACE

ROUGHNESS IN TURNING

This report submitted in accordance with requirement of the Universiti Teknikal

Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering

(Manufacturing Process)

by

NUR YASMIN BT ZULKIFLI

B050710001

FACULTY OF MANUFACTURING ENGINEERING

2011

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA

TAJUK: Application of Taguchi Method in the Optimization of Cutting Parameter

for Surface Roughness in Turning

SESI PENGAJIAN: 2010/11 Semester 2 Saya NUR YASMIN BT ZULKIFLI mengaku membenarkan Laporan PSM ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:

1. Laporan PSM adalah hak milik Universiti Teknikal Malaysia Melaka dan penulis. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan

untuk tujuan pengajian sahaja dengan izin penulis. 3. Perpustakaan dibenarkan membuat salinan laporan PSM ini sebagai bahan

pertukaran antara institusi pengajian tinggi.

4. **Sila tandakan (√)

SULIT

TERHAD

TIDAK TERHAD

(Mengandungi maklumat yang berdarjah keselamatan atau kepentingan Malaysia yang termaktub di dalam

AKTA RAHSIA RASMI 1972)

(Mengandungi maklumat TERHAD yang telah ditentukan

oleh organisasi/badan di mana penyelidikan dijalankan)

Alamat Tetap:

A4-L3-01, PPR Paya Nahu II,

08000, Sungai Petani,

Kedah.

Tarikh: _________________________

Disahkan oleh:

PENYELIA PSM

(Tandatangan dan Cop Rasmi) Tarikh: _______________________

** Jika Laporan PSM ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh laporan PSM ini perlu dikelaskan sebagai

SULIT atau TERHAD.

DECLARATION

I hereby, declared this report entitled “Application of Taguchi Method in The

Optimization of Cutting Parameter for Surface Roughness in Turning” is the results

of my own research except as cited in references.

Signature : ………………………………….....

Author’s Name : NUR YASMIN BINTI ZULKIFLI

Date : 17 MAY 2011

APPROVAL

This report is submitted to the Faculty of Manufacturing Engineering of UTeM

as a partial fulfillment of the requirements for the Degree in Bachelor of

Manufacturing Engineering (Manufacturing Process). The member of the

supervisory committee is as follow:

…………………………………..

Supervisor

(Signature & Official Stamp of Supervisor)

i

ABSTRAK

Kekasaran permukaan merupakan satu peranan penting dalam pelbagai bidang dan

ianya juga salah satu faktor yang amat penting dalam penilaian sesuatu ketepatan

pemesinan. Ini adalah kerana kekasaran permukaan memberikan impak yang besar

terhadap sifat-sifat mekanikal seperti sifat kelesuan, rintangan kakisan, rayapan dan

lain-lain. Kertas kajian ini membincangkan tentang aplikasi kaedah taguchi dalam

pengoptimuman faktor-faktor untuk menguji kekasaran permukaan dalam proses

melarik keluli lembut. Ujian dijalankan menggunakan ‘coated carbide’. Kelajuan

pemotongan yang digunakan ialah 1500 dan 2000rpm dengan ukuran kedalaman

pemotongan ialah 0.15 dan 0.17mm manakala kadar pemotongan ialah 0.020 dan

0.025mm/rev. Kajian ini menjurus kepada kesan kekasaran permukaan ketika

pemesinan dengan menggunakan kadar pemotongan yang berbeza semasa proses

melarik. Kaedah taguchi membantu untuk memilih atau menentukan syarat-syarat

optimum pemotongan untuk menjalankan eksperimen. Oleh itu, kekasaran

permukaan pada permukaan benda kerja akan diukur dengan menggunakan mesin

penyukatan kekasaran mudah alih. Kekasaran permukaan setiap benda kerja, akan

diukur untuk setiap pemotongan yang dijalankan. Hasil akan menunjukkan kesan

daripada perubahan pemotongan kepada kekasaran permukaannya.

ii

ABSTRACT

Surface roughness plays an important role in many areas and is a factor of great

importance in the evaluation of machining accuracy. This is because surface

roughness has large impact on the mechanical properties like fatigue behaviour,

corrosion resistance, creep life and etc. This study discusses the application of

taguchi method in the optimization of cutting parameter for surface roughness in

turning process of mild steel. The test carry out using coated carbide inserts. The

cutting speed use is 1500 and 2000rpm with depth of cut is 0.15 and 0.17mm while

feed rate is 0.020 and 0.025mm/rev. This study focuses on the effect of the surface

roughness while machining under different cutting parameters of the turning process.

The taguchi method helps to select or to determine the optimum cutting conditions

for the experiments. Thus the surface roughness of the workpiece will measure using

a portable roughness measuring machine. Surface roughness of every workpiece

under various cutting parameter will be measure as an impact to surface quality. The

result reveal of the effects of cutting parameters on responses like surface roughness.

iii

ACKNOWLEDGEMENT

I would like to thank for those who have reviewed and/or made contribution to this

project. I am especially Alhamdulillah to Allah s.w.t to give all the guidance and also

Blessing me, to the following indebted individuals especially to my Supervisor En.

Mohd Shukor Bin Salleh, for your kindness advises guidance in developing and

producing this work, moral support, until my Final Year Project completed. I am also

indebted to my parents for your kind always praying for my successful. I thank to our

lecturer in FKP, too numerous to mention, have shared their input and contribution

on how to make this project more effectives as a teaching and learning tool. To all

those who have helped, I expressed my sincere “Thanks”!

Last, but certainly not be least, continual encouragement and support of my family

and friends is deeply and sincerely appreciated.

DEDICATION

My Parents

Who has always been there for me and always prays for me,

My younger sister,

My friends

Who has support me,

iv

TABLE OF CONTENT

Abstrak i

Abstract ii

Acknowledgement iii

Table of content iv

List of tables vii

List of figures viii

List abbreviations x

1. INTRODUCTION

1.1 Background 1

1.2 Problem Statement 2

1.3 Objectives 3

1.4 Scope 3

1.5 Structure of the report 4

1.5.1 Chapter 1: Introduction 4

1.5.2 Chapter 2: Literature review 4

1.5.3 Chapter 3: Methodology 4

1.5.4 Chapter 4: Result 4

1.5.5 Chapter 5: Discussion and analysis 4

1.5.6 Chapter 6: Conclusion and recommendations 4

1.6 PSM 1 Gantt Chart 5

1.7 PSM 2 Gantt Chart 6

2 LITERATURE REVIEW

2.1 Material selected 7

2.2 Turning features 10

2.2.1 Cutting tool material 12

2.2.2 Cutting operation 14

2.2.3 Surface roughness 16

2.2.3.1 Measuring surface roughness 19

v

2.2.4 Types of chip produced 20

2.2.4.1 Continuous chips 20

2.2.4.2 Built-up edge chips 22

2.2.4.3 Serrated chips 24

2.2.4.4 Discontinuous chips 24

2.2.5 Tool life 26

2.3 Cutting parameters 28

2.3.1 Cutting speed 28

2.3.2 Feed 29

2.3.3 Depth of cut 29

2.4 Taguchi method 30

3 METHODOLOGY

3.1 Objective of the experiment 35

3.2 Research flow chart 36

3.3 Design of experiment-Taguchi method 37

3.3.1 Variable machining parameter 37

3.3.2 Design of experiment matrix 37

3.3.3 Response variables 38

3.4 Material preparation 38

3.4.1 Workpiece 38

3.5 Cutting tool material 39

3.5.1 Coated carbide 39

3.6 Machine preparation 40

3.6.1 CNC lathe machine 40

3.7 Test and measurement 41

3.7.1 Surface roughness measurement 41

3.7.2 Eliminate error 44

3.8 Data analysis 44

3.9 Discussion on the result 45

3.10 Conclusion and recommendation 45

vi

4 RESULTS

4.1 Introduction 46

4.2 Measurement Results 46

4.3 D.O.E Results 47

4.3.1 Main Effects Plot for Means 48

4.3.2 Main Effects Plot for S/N Ratios 51

4.3.3 Analysis of Variance for Means (ANOVA) 54

4.3.4 Predicted Value of Surface Roughness 55

5 DISCUSSION

5.1 Introduction 57

5.2 Surface Roughness Numerical Analysis 57

5.3 Surface Roughness D.O.E Graphical Analysis 60

6 CONCLUSION AND RECOMMENDATION 62

REFERENCES 63

APPENDICES

A

vii

LIST OF TABLES

2.1 Mechanical properties of mild steel 8

2.2 Thermal properties of mild steel 9

2.3 Processability of mild steel 9

2.4 Durability of mild steel 10

2.5 Mechanical properties of cutting tool 12

2.6 Thermal properties of cutting tool 13

2.7 Processability of cutting tool 13

2.8 Durability of cutting tool 13

2.9 Factors influencing machining operations 15

2.10 Factors affecting surfaces roughness 18

2.11 Cutting speed for some common metals 29

2.12 Key features of review study 33

2.13 Comparing DOE and Taguchi methods 34

3.1 Variable machining parameters 37

3.2 Design of experiment matrix 38

3.3 The function of surface roughness measuring machine accessories 42

4.1 Surface roughness result for set A 46

4.2 Surface roughness result for set B 47

4.3 Response table for means for set A 49

4.4 Response table for means for set B 51

4.5 Response table for Signal to noise ratio for set A: Smaller is better 52

4.6 Response table for Signal to noise ratio for set B: Smaller is better 53

4.7 Predicted value of surface roughness 55

4.8 Factor levels for predictions 56

5.1 Controllable Parameter Setting 59

5.2 Optimum Parameter Effect 60

viii

LIST OF FIGURES

2.1 Basic metal cutting theory 11

2.2 Process schematic, turning, boring and parting operations

performed on a lathe 14

2.3 Effect of feed rate and edge preparation on shearing force

and ploughing force 17

2.4 Effect of feed rate and edge preparation on surface roughness

of the machined workpiece 17

2.5 Measuring surface roughness with a stylus. The rider supports

the stylus and guards against damage 19

2.6 Path of the stylus in surface roughness measurements

(broken line) compared to the actual roughness profile 20

2.7 Continuous chip with narrow, straight and primary shear zone 21

2.8 Continuous chip with secondary shear zone at the chip-tool

interface 22

2.9 Built- up edge 23

2.10 Hardness distribution with a built-up edge in the cutting zone 23

2.11 Surface finish produced in turning 5130 steel with a BUE 23

2.12 Segmented or nonhomogeneous chip 24

2.13 Discontinuous chip 25

2.14 Flank wear 26

2.15 Crater wear 27

2.16 Chipped cutting edge 27

2.17 Thermal cracking on rake face 27

2.18 Built-up edge 27

2.19 Catastrophic failure 28

2.20 Schematic illustration of the turning operation showing various

features 30

3.1 Research flow chart 36

3.2 Workpiece 39

ix

3.3 Inserts Coated Carbide 39

3.4 CNC lathe machine 40

3.5 Portable roughness measuring machine 41

3.6 Portable roughness measuring accessories 42

3.7 Stylus 42

3.8 Surface roughness of mild steel bar 43

3.9 Surface roughness result 44

4.1 Main Effects Plot for set A 48

4.2 Main Effects Plot for set B 50

4.3 Main Effect Plot for Signal to Noise Ratios Graph for set A 51

4.4 Main Effect Plot for Signal to Noise Ratios Graph for set B 53

4.5 Analysis of Variance for Means 54

5.1 Average Ra value against number of sample bar graph 58

x

LIST OF ABBREVIATIONS

CNC - Computer Numerical Control

UTeM - Universiti Teknikal Malaysia Melaka

PSM - Projek Sarjana Muda

AISI - American Iron and Steel Institute

SAE - Society of Automotive engineers

TiC - Titanium carbide

TiCN - Titanium carbonitride

CVD - Chemical vapour deposition

PVD - Physical vapour deposition

Ra - Average surface roughness value

BUE - Built-up edge

PDE - Parameter Design Experiment

S/N - Signal-to-noise

MRR - Material Removal Rate

DOE - Design of experiment

FKP - Fakulti Kejuruteraan Pembuatan

1

CHAPTER 1 INTRODUCTION

1.1 Background

The challenge of modern machining industries is mainly focused on the achievement

of high quality, in terms of work piece dimensional accuracy, surface finish, high

production rate, less wear on the cutting tools, economy of machining in terms of

cost saving and increase the performance of the product with reduced environmental

impact (Hasan, 2007). Surface roughness plays an important role in many areas and

is a factor of great importance in the evaluation of machining accuracy (Palanikumar,

2006). Surface roughness, an indicator of surface quality is one of the most specified

customer requirements in a machining process. For efficient use of machine tools,

optimum cutting parameters (cutting speed, feed rate and depth of cut) are required.

So it is necessary to find a suitable optimization method which can find optimum

values of cutting parameters for minimizing surface roughness.

In turning operation, it is an important task to select cutting parameters for achieving

high cutting performance. Usually, the desired cutting parameters are determined

based on experience or by use of hand book. But the ranges given these sources are

actually starting values and not the optimal values. However, this does not ensure

that the selected cutting parameters have optimal or near optimal cutting performance

for a particular machine and environment (Srikanth, 2008). Since turning is the

primary operation in most of the production processes in the industry, surface finish

of turned components has greater influence on the quality of the product. Surface

finish in turning has been found to be influenced in varying amounts by a number of

2

factors such as feed rate, work material characteristics, work hardness, unstable built-

up edge, cutting speed, depth of cut, cutting time, and tool nose radius.

The Taguchi method is statistical tool, adopted experimentally to investigate

influence of surface roughness by cutting parameters such as cutting speed, feed rate

and depth of cut. The Taguchi process helps to select or determine the optimum

cutting conditions for turning process. Many researchers developed many

mathematical models to optimize the cutting parameters to get lowest surface

roughness by turning process. The variation in the material hardness, alloying

elements present in the work piece material and other factors affecting surface finish

and tool wear. The Taguchi design of experiments was used to optimize the cutting

parameters and it is a powerful tool for the design of high quality systems. It

provides simple, efficient and systematic approach to optimize designs for

performance, quality and cost. Taguchi method is efficient method for designing

process that operates consistently and optimally over a variety of conditions. To

determine the best design it requires the use of a strategically designed experiment.

Taguchi approach to design of experiments in easy to adopt and apply for users with

limited knowledge of statistic, hence gained wide popularity in the engineering and

scientific community. The desired cutting parameters are determined based on

experience or by hand book. Cutting parameters are reflected on surface roughness,

surface texture and dimensional deviation turned product. In a manufacturing process

it is very important to achieve a consistence tolerance and surface finish. Taguchi

method is especially suitable for industrial use, but can also be used for scientific

research (Hasan, 2007).

1.2 Problem statements

Cutting parameters and surface roughness of mild steel has to be studied in this

project. In machining operation, the quality of surface finish is an important

requirement for many turned workpieces. This project presents a study of application

of Taguchi method in the optimization of cutting parameter for surface roughness in

turning which allow it to be examined in more detail.

3

For this research study, it is targeted to find out the answer for the following

questions:

1. What are the roles of optimized cutting parameters (cutting speed, feed rate

and depth of cut) of the turning process for controlling the required surface

roughness?

2. How Taguchi process helps to select or to determine the optimum cutting

conditions for turning process?

3. How surface roughness plays an important role in many areas and is a factor

of great importance in the evaluation of machining accuracy?

1.3 Objectives

The objectives of this study are as follow:

1. To find the optimal cutting parameters for surface roughness in turning.

2. To define the number of levels for the process parameters and possible

interaction between the process parameters.

3. To select the appropriate orthogonal array and assign of process parameters

for the orthogonal array.

1.4 Scope

This project will involve machining by CNC turning in UTeM machine shop. Mild

steel will be used as workpiece and coated carbide as a cutting tool in this project.

This project will focused on cutting parameters and surface roughness in turning by

Taguchi method.

4

1.5 Structure of the report

The summary of each chapter was described in the structure of report. The structure

of the report includes Chapter 1 until Chapter 6 of the report.

1.5.1 Chapter 1: Introduction

This chapter includes the background of the project, problem statement, objectives,

scope and project management of the whole project.

1.5.2 Chapter 2: Literature review

Literature review on cutting parameters, surface roughness, material used which is

mild steel and inserts used (coated carbide).

1.5.3 Chapter 3: Methodology

This chapter describes the methodology of the project that contains a brief

explanation about the work piece preparation (mild steel), preparation of the

machine, the analysis of cutting parameter and surface roughness, discussion and

conclusion.

1.5.4 Chapter 4: Result

1.5.5 Chapter 5: Discussion and Analysis

1.5.6 Chapter 6: Conclusion and Recommendations

5

No. Task Week

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

1 Selection of PSM title

2 PSM title selected and filled the form

3 Research, study and understand the synopsys of title

4 Find all informations, journal and references book

5 Discuss the objectives and scopes with supervisor

6 Rework and make correction for objectives and scopes

7 Meet and discuss the progress of PSM with supervisor

8 Implement introduction and literature review

9 Review the introduction and literature review by supervisor

10 Make flow chart for preparing specimens, experiments

11 Implement methodology chapter

12 Review methodology by supervisor

13 Make a correction for methodology chapter

14 Complete the report and submit to supervisor

15 Preparation for oral presentation

16 Presentation PSM 1

Table 1.1: Gantt chart for PSM 1

Planning Actual

6

No. Task Week

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

1 Improvement on PSM 1

2 Additional literature review, books and journal

3 Material and Tool Preparation

4 Machine Preparation

5 Discussion with supervisor

6 Start machining the project

7 Collection data

8 Chapter 4- correction after comment by supervisor

9 Chapter 5 - correction after comment by supervisor

10 Chapter 6 - correction after comment by supervisor

11 Final correction on report writing

12 Transferring paper work into journal

13 Final editing

14 Hard cover binding

15 Submission PSM report

16 Presentation and slide preparation

Table 1.2: Gantt chart for PSM 2

Planning Actual

7

CHAPTER 2 LITERATURE REVIEW

2.1 Material selected

Carbon steel is sometimes referred to as 'mild steel' or 'plain carbon steel'. The

American Iron and Steel Institute defines a carbon steel as having no more than 2 %

carbon and no other appreciable alloying element. Carbon steel makes up the largest

part of steel production and is used in a vast range of applications. Typically carbon

steels are stiff and strong. Carbon also exhibit ferromagnetism, which means it is

magnetic. This means it is extensively used in motors and electrical appliances.

Welding carbon steels with carbon content greater than 0.3 % requires special

precautions be taken. However, welding carbon steel presents far fewer problems

than welding stainless steels. The corrosion resistance of carbon steels is poor which

means it rust and so it should not be used in a corrosive environment unless some

form of protective coating is used.

Mild steel is a carbon steel typically with a maximum of 0.25% Carbon and 0.4% -

0.7% manganese, 0.1%-0.5% Silicon and some traces of other elements such as

phosphorous, it may also contain lead or sulphur is made of mild steel, even some of

your pots and pans are. Mild steel is a general term for a range of low carbon (a

maximum of about 0.3%) steels that have good strength and can be bent, worked or

can be welded into an endless variety of shapes for uses from vehicles like cars and

ships to building materials. (K.Muniswaran, 2007)

8

Advantages

Cheap

Wide variety available with different properties

High stiffness

Magnetic

Most carbon steels are easy machine and weld

It is often used when large amounts of steel are needed.

Disadvantages

Poor corrosion resistance like rusts.

Table 2.1: Mechanical properties of mild steel (Geocities, 2010)

Mechanical properties

Young's Modulus 200 - 215 GPa

Shear Modulus 79 - 84 GPa

Bulk modulus 158 - 175 GPa

Poisson's Ratio 0.285 - 0.295

Hardness - Vickers 107.5 - 172.5 HV

Elastic Limit 250 - 395 MPa

Tensile Strength 345 - 580 MPa

Compressive Strength 250 - 395 MPa

Elongation 26 - 47 %

Endurance Limit * 203 - 293 MPa

Fracture Toughness * 41 - 82 MPa.m^1/2

Loss Coefficient * 8.9e-4 - 1.42e-3

9

Table 2.2: Thermal properties of mild steel (Geocities, 2010)

Thermal properties

Thermal conductor or insulator? Good conductor

Thermal Conductivity 49 - 54 W/m.K

Thermal Expansion 11.5 - 13 µstrain/°C

Specific Heat 460 - 505 J/kg.K

Melting Point 1480 - 1526 °C

Maximum Service Temperature * 200 - 350 °C

Minimum Service Temperature * -68.15 - -38.15 °C

Impact on the environment

The production energy of steel is comparatively low - per unit weight, about a half

that of polymers; per unit volume, though, twice as much. Carbon steels are easy to

recycle, and the energy to do so is small.

Table 2.3: Processability of mild steel (Geocities, 2010)

Processability (Scale 1 = impractical to 5 = excellent)

Castability 3

Formability 4 - 5

Machinability 3 - 4

Weldability 5

Solder/Brazability 5