Performance evaluation of different process conditions when hard turning ASSAB 760

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PERFORMANCE EVALUATION OF DIFFERENT PROCESS CONDITIONS WHEN HARD TURNING ASSAB 760

AZRI BIN AZMAN

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PERFORMANCE EVALUATION OF DIFFERENT PROCESS CONDITIONS WHEN HARD TURNING ASSAB 760

AZRI BIN AZMAN

A project report submitted in partial fulfillment of the requirements for the award of the degree of Master of Engineering

(Mechanical - Advanced Manufacturing Technology)

Faculty of Mechanical Engineering Universiti Teknologi Malaysia

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To my beloved parents

Azman Shamaan & Khairiah Abdullah

To my beloved wife and son

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ACKNOWLEDGEMENTS

In the name of Allah, the most Gracious and most Compassionate

I would like to thank Allah Almighty for the blessings and giving me strength to complete this thesis. I am indebted to all who helped directly or indirectly to complete this project report.

I would like to thank Prof. Dr. Noordin Mohd Yusof (supervisor) and others lecturers in this programme for their valuable experiences, comments, suggestions, guidance and advice throughout the project. There are no doubts that their valuable comments and suggestions have influenced and enhanced this project report. A special thanks are due to many other individuals and organizations that have been involved with this project in one form or another.

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ABSTRACT

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ABSTRAK

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TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION Ii

DEDICATION Iii

ACKNOWLEDGEMENTS Iv

ABSTRACT V

ABSTRAK Vi

TABLE OF CONTENTS Vii

LIST OF TABLES X

LIST OF FIGURES Xi

LIST OF ABBREVIATIONS AND SYMBOLS Xiii

LIST OF APPENDICES Xiv

1 INTRODUCTION 1

1.1 Background 1

1.2 Problem Statement 2

1.3 Objective of Study 4

1.4 Significant of The Study 4

1.5 Scope of The Study 4

1.6 Overview of The Methodology 4

1.7 Thesis Organization 5

2 LITERATURE REVIEW 6

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2.1.1 Basic Metal Cutting Theory 6

2.2 Orthogonal Cutting and Oblique Cutting 7

2.3 Temperature in Metal Cutting 9

2.4 Turning Operation 11

2.5 Cutting Tool - Insert 12

2.6 Cutting Tool Geometry 13

2.6.1 Rake Angle 14

2.6.2 Side Rake Angle 15

2.6.3 Cutting –Edge Angle 15

2.6.4 Relief Angle 15

2.6.5 Nose Radius 16

2.7 Surface Roughness 17

2.7.1 Introduction 17

2.8 Tool and Tool Material 19

2.8.1 High Speed Steel 19

2.8.2 Carbide Tools 19

2.8.2.1 Coated Carbides 20

2.8.3 Ceramic 21

2.8.4 Cermets 22

2.8.5 Poly crystalline Cubic Boron Mitride 22

2.9 Tool Wear r 23

2.10 Tool Failure Mode 24

2.11 Mechanism of Cutting Tool Wear 25

2.12 Chips Morphology 27

2.13 Chips Forms 27

2.14 Design of Experiment 30

2.14.1 Introduction 30

2.14.2 Response Surface Methodology 31

2.15 Summary of Literature Review 39

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3.1 Introduction 40

3.2 Research Methods and Proceduresl 41

3.3 Machines 41

3.4 Measuring equipment 42

3.5 Workpiece Material 44

3.6 Cutting Insert 45

3.7 Tool Wear Observation Equipment 46

3.8 Experimental Details 47

3.8.1 Cutting Condition 47

3.8.2 Workpiece Preparation 47

3.8.3 Surface Roughness Measurement 48

3.9 Experiment Designs 49

3.10 Flowchart Outline 51

4 EXPERIEMENTAL RESULTS 52

4.1 Introduction 52

4.2 ANOVA analysis for 1st Order Response Model 53 4.3 ANOVA analysis for 2nd Order Response Model 54

4.4 Conformation of The Model 65

4.5 Tool Wear Forms 66

4.6 Chip Form 73

4.7 Summary 74

5 DISCUSSIONS 75

5.1 Introduction 75

5.2 Cutting Condition 76

5.2.1 Cutting Speed 76

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5.2.3 Depth of Cut 78

5.3 Tool Wear 79

5.4 Chip Form 80

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REFERENCE 81

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LIST OF TABLE

TABLE NO. TITLE PAGE

2.1 ISO-based chip forms classification 28

2.2 Chip form classification 29

3.1 Chemical composition of ASSAB 760 steel 44

3.2 Physical properties of ASSAB 760 45

3.3 Independent variables for experiment design 47 3.4 Two level, full factorial experiment with three factors 49

3.5 Second order level design experiment 50

4.1 ANOVA Results – First Order Response Surface Model 53

4.2 Experimental design and results 55

4.3 ANOVA Results–Second Order Response Surface Model 56

4.4 Standard Deviation and R-Squred 56

4.5 Confirmation test 66

4.6 Top view of initial tool wear 67

4.7 Side view of tool flank wear 70

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LIST OF FIGURE

FIGURE NO. TITLE PAGE

1.1 Fishbone diagram with factors that influence on surface 2 roughness

2.2.2 The main cutting data/tool elements for turning tool 12 applications

2.3.4 Comparative Characteristics of Related Alloys/Tempers 16 2.4.1 Arithmetical Mean Roughness (Ra) graph 18

2.4.2 Maximum Peak (Ry) graph 18

2.4.3 Ten-point Mean Roughness (Rz) graph 19

2.5.1 General model of a process 21

2.5.3.1 The 23 factorial design 24

2.5.3.2 Geometric presentation of contracts corresponding to 27 the main effects and interaction in the 23 design

2.6.3 First order response surface and path of steepest ascent 32

3.1.1.1 CNC Turning DMG CTX 310 Glidimiester 35

3.1.1.2 Technical Data for CNC Turning DMG CTX 310 36 Glidimiester

3.1.2 Tool Holders for Negative Insert 37

3.1.3 Indexable Inserts for Turning 38

3.1.4.1 Mitutoyo Surface Roughness Tester SJ-400 39

3.1.4.2 Surface Roughness compensation 40

3.3.1 Illustration of workpiece dimension 44

3.3.2 Experimental setup 45

3.3.3 Factorial 24 design for the surface finish experiment 46

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FIGURE NO. TITLE PAGE

4.2.1 Illustration of workpiece dimension 54

4.2.2 The normal probability plots of residuals for surface 59 roughness

4.2.3 The plots of the residuals versus the predicted response 60 for surface roughness

4.2.4 Ra contours in feed-tool length plane at cutting speed of 61 230 m/min and depth of cut 0.15 mm

4.2.5 3D surface model in feed-tool length plane at cutting 61 speed of 230 m/min and depth of cut 0.15 mm

4.2.6 Desirability contours in feed-tool length plane at cutting 63 speed of 280 m/min and depth of cut 0.15 mm

4.2.7 3D surface model in feed-tool length plane at cutting 63 speed of 230 m/min and depth of cut 0.15 mm

4.4.1 Interaction Feed-Tool Length factor at CS 230 mm/min 66 and DOC 0.15 mm. D- (22mm) D+ (52mm)

4.4.2 4.4.2 Cutting speed factor at depth of cut 0.15 mm 67 feed rate of 0.12 mm/rev and tool length 37 mm

4.5 Tool wear classification according to Metalcutting 68 Technical Guide

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LIST OF ABBREVIATIONS AND SYMBOLS

D, d - Diameter

 - Rake Angle

CS - Cutting Speed

DOC - Depth of Cut

f - Feed Rate

l - Tool Overhang Length

Ra - Mean Roughness

Ry - Maximum Peak

Rz - Ten-point Mean Roughness

Sm - Mean Spacing

tm - Machining times

ANOVA - Analysis of Variance

RPM - Revolution per Minutes

DOE - Design of Experiment

RSM - Response Surface Methodology

α - Significance Level

CCD - Central Composite Design

Ft - Tangential force

Ff - Feed force

Fr - Radial force

Vc - Cutting speed

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LIST OF APPENDICES

APPENDIX TITLE PAGE

A Experiment Data 86

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CHAPTER 1

INTRODUCTION

1.1 Background

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1.2 Problem Statement

The term machinability refers to the ease with which a metal can be machined to an acceptable surface finish. Materials with good machinability require little power to cut, can be cut quickly, easily obtain a good finish, and do not wear the tooling much; such materials are said to be free machining. The factors that typically improve a material's performance often degrade its machinability. Therefore, to manufacture components economically, engineers are challenged to find ways to improve machinability without harming performance.

Machinability can be difficult to predict because machining has so many variables. In most cases, the strength and toughness of a material are the primary factor. Strong, tough materials are usually more difficult to machine simply because greater force is required to cut them. Other important factors include the chemical composition, thermal conductivity and microstructure of the material, the cutting tool geometry, and the machining process parameters.

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1.3 Objective Of Study

This study is carried out as to evaluate the effect of cutting conditions on surface roughness and tool wear when hard turning steel hardened to (399 HB). Expectation of this study will consist of:

i) To evaluate the effects of different process conditions on hard turning performance.

ii) To develop a mathematical model for predicting the surface roughness of hard turned part by using the design of experiment approach.

iii) To observed the initial tool wear and the form of the chips produced during the hard turning operation.

1.4 Significance of The Study

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1.5 Scope Of The Study

The scopes of this experiment are as follows:

(i) The performance was primarily evaluated in terms of surface roughness. The chip form and the initial tool wear were also be observed.

(ii) Work piece material used is ASSAB 760 steel hardened to 399HB. (iii) Process conditions investigated are cutting speed, feed and depth of cut. (iv) Dry cutting machining conditions used.

1.6 Overview of The Methodology

The following methodology used as guidance to achieve the study objectives. (i) Based on the previous literature review and recommendation for

manufacturer

(ii) Select the proper cutting condition and discuss with supervisor. (iii) Planning and design a reliable design of experiment.

(iv) Design experiment consist of::

 Surface roughness measurement using stylus instrument.  Initial form tool wear observation using optical microscope.

(v) Data analysis and validation.

 Evaluate the effect of cutting parameter on the surface roughness  Determine the effect of cutting parameter on the cutting tool initial form

wear

 Develop a mathematical model between the cutting parameter and surface

roughness

(vi) Data analysis and validation consist of:

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 Determine the interaction between cutting condition and surface

roughness.

 Determine the effect of cutting condition on cutting tool edge on a fixed

length.

1.7 Thesis Organization