UNIVERSITI TEKNIKAL MALAYSIA MELAKA

SURFACE FINISH STUDY OF MILD STEEL MACHINED BY

CARBIDE CUTTING TOOLS

This report submitted in accordance with requirement of the Universiti Teknikal

Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering (Manufacturing Process) with Honours.

By

MOHD FAIZAL BIN MOHAMAD

FACULTY OF MANUFACTURING ENGINEERING 2010

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)

(TANDATANGAN PENULIS)

Alamat Tetap: No 404, Blok 17, F. Keratong 7,

26700 Muadzam Shah,

Pahang Darul Makmur.

Tarikh:

Disahkan oleh:

(TANDATANGAN PENYELIA)

Cop Rasmi:

Tarikh: _______________________

* Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan, atau disertai bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (PSM). ** Jika tesis ini SULIT atau TERHAD, sila lampirkan surat daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD.

BORANG PENGESAHAN STATUS TESIS*

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

JUDUL: Surface Finish Study of Mild Steel Machined by Carbide Cutting Tools

SESI PENGAJIAN: 2009/2010

Saya _______ MOHD FAIZAL BIN MOHAMAD__________ mengaku membenarkan tesis (PSM/Sarjana/Doktor Falsafah) ini disimpan di Perpustakaan Universiti Teknikal Malaysia Melaka (UTeM) dengan syarat-syarat kegunaan seperti berikut:

1. Tesis adalah hak milik Universiti Teknikal Malaysia Melaka. 2. Perpustakaan Universiti Teknikal Malaysia Melaka dibenarkan membuat salinan

untuk tujuan pengajian sahaja. 3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran

antara institusi pengajian tinggi.

4. **Sila tandakan (√)

(HURUF BESAR)

ii

DECLARATION

I hereby declare that this report entitled “SURFACE FINISH STUDY OF MILD

STEEL MACHINED BY CARBIDE CUTTING TOOLS” is the results of my own

research except as cited in references.

Signature :

Author’s Name : MOHD FAIZAL BIN MOHAMAD

Date :

iii

APPROVAL

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

partial fulfillment of the requirements for the degree of Bachelor of Manufacturing

Engineering (Manufacturing Process) with honour. The members of the supervisory

committee are as follow:

…………………………………………….

MR. SHUKOR BIN SALLEH (PSM Supervisor)

iv

ABSTRACT

The main goal of this project is to analyze the effects of the parameters on surface

roughness in turning process. Generally there are three parameters that will affect the

surface roughness which are cutting speed, feed rate and depth of cut. Roughness is a

measure of the texture on 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 and if it is

small the surface is smooth. Surface roughness constitutes one of the most critical

constraints for the selection of machine tools and cutting parameters in metal cutting

operations. In this study, the Taguchi’s method was used to study the effects of cutting

parameters which are cutting speed, feed rate and depth of cut. The material used in this

research was mild steel AISI 1020. Machining trials was conducted at different cutting

conditions using carbide cutting tools. Surface roughness values were measured using

surface roughness tester. It was shown that feed rate was given the highest influence of

the surface roughness. The study is importance to machinist in the selection of

appropriate combinations of machining parameters for high-speed turning of mild steel

AISI 1020 workpiece using carbide cutting tool. The experimental results reveal that the

most significant machining parameter for surface roughness is feed rate followed by

depth of cut and cutting speed.

v

ABSTRAK

Matlamat utama projek ini adalah untuk menganalisis kesan parameter terhadap

kekasaran permukaan produk semasa proses melarik. Umumnya terdapat tiga parameter

yang member kesan kepada kekasaran permukaan dimana ianya adalah halaju

pemotongan, kadar suapan dan kedalaman pemotongan. Kekasaran ialah pengukuran

tekstur sesuatu permukaan. Kekasaran permukaan merupakan salah satu perkara yang

paling penting untuk pemilihan peralatan mesin dan parameter permotongan dalam

operasi pemotongan logam. Di dalam kajian ini, ‘Taguchi method’ akan digunakan

untuk mengkaji kesan parameter pemotongan dimana ianya adalah halaju pemotongan,

kadar suapan dan kedalaman pemotongan ke atas kekasaran permukaan benda kerja

yang akan dimesin di mana ianya adalah ‘mild steel AISI 1020’. Pemesinan yang akan

dijalankan mengikut parameter pemotongan yang berbeza menggunakan alat pemotong

karbida. Nilai kekasaran permukaan akan diukur menggunakan penguji kekasaran

permukaan. Hasil daripada kajian ini menunjukkan kadar suapan memberikan kesan

yang paling tinggi terhadap kekasaran permukaan benda kerja. Kajian ini penting kepada

operator pemesinan untuk memilih kombinasi parameter mesin yang sesuai di dalam

pemesinan kelajuan tinggi terhadap benda kerja iaitu ‘mild steel AISI 1020’

menggunakan alat pemotong karbida. Hasil daripada kajian ini menunjukkan bahawa

kadar suapan memberikan kesan yang paling besar diikuti oleh kedalaman pemotongan

dan halaju pemotongan.

vi

DEDICATION

To my dearest parents, Mohamad Bin Md. Saman and Zaliha Binti Ismail

for their love, care and supports.

vii

ACKNOWLEDGEMENT

In the Name of ALLAH The Most Gracious, Most Merciful

First of all, thanks to ALLAH S.W.T for giving me the strength and patience in order to

accomplish the research of my final year project.

I would like to express my deepest appreciation to my supervisors, Mr. Shukor

bin Salleh for the guidance, encouragement, and feedback he provided to me during the

final year project process.

I especially would like to thank my mother, brother and sisters for their support

and encouragement. Lastly, I would like to thank everyone who directly or indirectly

involved through contribution of ideas, materials, as well as professional opinions until

this project had been successfully done.

viii

TABLE OF CONTENTS

Declaration ii

Approval iii

Abstract iv

Abstrak v

Dedication vi

Acknowledgement vii

Table of Contents viii

List of Figures iv

List of Tables v

List of Abbreviations, Signs, and Symbols vi

CHAPTER 1: INTRODUCTION 1

1.1 Background of Project 1

1.2 Problems Statements 6

1.3 Objectives of Project 7

1.4 Scope of Project 7

1.5 Report Outline 8

1.6 Gantt Chart 9

CHAPTER 2: LITERATURE REVIEW 11

2.1 Introduction 11

2.2 Machining Process 13

2.2.1 Type of Metal Cutting 12

2.2.1.1 Types of Production 14

2.2.2 CNC Lathe Machine 15

2.2.3 Automatic Tool Changers 15

2.2.4 Manual Tool Changing 16

ix

2.3 Cutting Tool Material 16

2.3.1 Carbide Inserts Turning 17

2.4 Machining Parameters 17

2.4.1 Cutting Speed 17

2.4.2 Feed Rate 18

2.4.3 Depth of Cut 19

2.5 Surface Roughness 22

2.5.1 Introduction of Surface Metrology 24

2.5.2 Roughness 25

2.5.3 Waviness 25

2.5.4 Method to Analyze Surface Roughness 25

2.5.4.1 Average Roughness (Ra) 25

2.6 Cutting Fluids 27

2.6.1 Functions of Cutting Fluids 27

2.7 Taguchi’s Method 28

2.8 Prediction the Result by Pass Research about the Surface Integrity 30

CHAPTER 3: METHODOLOGY 32

3.1 Introduction 32

3.2 Planning 33

3.3 Selection of Machine and Equipment 33

3.3.1 Selection of Machine 33

3.3.1.1 CNC Lathe Machine 33

3.4 Selection of Workpiece Material 36

3.4.1 Mild Steel 36

3.5 Selection of method for Analysis 38

3.5.1 Method to Analyze Surface Roughness 38

3.5.2 Surface Roughness Measurement 40

3.5.3 Surface Roughness Tester (SJ-301) Procedure 41

x

3.6 Experiment Procedure 41

3.6.1 Experimental Design 41

3.6.2 Cutting Parameters 42

3.6.3 Experiment Flowchart 44

3.7 Lab Sheet Design 45

CHAPTER 4: RESULTS AND ANALYSIS 46

4.1 Introduction 46

4.2 Design of Experiment 47

4.3 Findings and Data Analysis of Surface Roughness 48

4.3.1 Interaction Plot for SN ratios (Feed Rate) 49

4.3.2 Interaction Plots for SN ratios (Depth of Cut) 50

4.3.3 Effect of Control Parameters on Surface Roughness 51

4.3.4 ANOVA Table for response function of the surface roughness 54

4.4 Predicted Result at Optimum Setting Condition 55

4.4.1 Confirmation Test 55

4.4.2 Comparison Test Result 56

CHAPTER 5: DISCUSSION 57

5.1 Introduction 57

5.2 Machining Parameter Analysis 58

5.3 Surface Roughness Analysis 58

5.3.1 Feed Rate 59

5.3.2 Cutting Speed 59

5.3.3 Depth of Cut 60

5.3.4 Other Factors 61

CHAPTER 6: CONCLUSION AND RECOMMENDATION 62

6.1 Conclusion 62

6.2 Recommendation 63

6.2.1 Workpiece 63

xi

6.2.2 Machine 63

6.2.3 Cutting Tool 63

6.2.4 Design of Experiments 64

6.2.5 Mathematical Modeling 64

REFERENCES 65

xii

LIST OF FIGURE

Figure

1.1

1.2

2.1

2.2

2.3

3.1

3.2

3.3

3.4

3.5

3.6

4.1

4.2

4.3

Description

Conventional lathe

CNC turning machine Surface roughness profile

Roughness, waviness, lay and flaw

Average roughness (Ra)

Project flowchart

HAAS CNC lathe machine

Mild steel AISI 1020

Portable surface roughness tester

Distance of measurement on top surfaces in plan view of test

piece

Flow chart for experiment procedure

Interaction Plot for SN ratios (Feed Rate)

Interaction Plot for SN ratios (Depth of Cut)

Mean S/N Graph for Surface Roughness

Page

3

4

23

24

26

34

35

36

38

40

44

49

50

53

xiii

LIST OF TABLE

Table

1.1

1.2

2.1

2.2

3.1

3.2

3.3

3.4

3.5

4.1

4.2

4.3

4.4

4.5

4.6

4.7

4.8

Description

Gantt chart for PSM 1

Gantt Chart for PSM 2

Suggested operating parameters for machining various materials

with carbide tools

General recommendations for turning operations

Composition of AISI standard mild steel AISI 1020

Mechanical properties of mild steel at room temperature

General specification of Mitutoyo surface roughness tester

Cutting parameters

Cutting conditions and response

Variable levels used in the experimentation

Experimental result for surface roughness

Types of Characteristics and Formula

Response Table for Signal to Noise Ratios Smaller is better

ANOVA table for response function of the surface roughness

Factors levels for prediction

Confirmation test results

Comparison of predicted and experimented results

Page

9

10

20

21

37

37

39

42

42

47

48

51

52

54

55

55

56

xiv

LIST OF ABBREVIATIONS, SIGNS, AND SYMBOLS

AISI - American Iron and Steel Institute

C - Carbon

Cu - Cooper

FKP - Fakulti Kejuruteraan Pembuatan

Mn - Manganese

P - Phosphorus

PSM - Projek Sarjana Muda

Ra - arithmetic mean value (roughness average)

Rpm - revolution per minute

Rq - root mean square average

S - Sulfur

UTeM - Universiti Teknikal Malaysia Melaka

USA - United State of America

ATC - Automatic tool changer

CNC - Computer Numerical Control

AA - Arithmetic average

CLA - Center line average

ANOVA - Analysis of Variances

1

CHAPTER 1 INTRODUCTION

1.1 Background of Project

Surface roughness and tolerances are among the most critical quality measures in many

mechanical products. As competition grows closer, customers have increasingly focused

on quality, making surface roughness become one of the most competitive dimensions in

today’s manufacturing industries. Surface of a mechanical product can be created with a

numbers of manufacturing processes.

Surface roughness is an important measure of the technological quality of a product and

a factor that greatly influence manufacturing costs. The mechanism behind the formation

of surface roughness is very dynamic, complicated and process dependent and it is very

difficult to calculate its value through theoretical analysis.

Mild steel is used in this project which sometimes it referred to as 'carbon steel' or 'plain

carbon steel'. Carbon steel makes up the largest part of steel production and is used in a

vast range of applications. As others material, it also have its own advantages which are

cheap, high stiffness, strong, magnetic and most of it are easy machine and weld.

However, this material also has its own disadvantage which is poor corrosion resistance.

2

This research applies Taguchi’s method approach to studying the impact of turning

parameters on the roughness of turned surfaces. Taguchi’s method approach is quality

control methodology that combines control charts and process control with product and

process design to achieve a robust total design. It aims to reduce product variability with

a system for developing specifications and designing them into a product or process.

Named after its inventor, the Japanese engineer-statistician Dr. Genichi Taguchi who

also developed the quality loss function.

Taguchi Method is a process or product optimization method that is based on 8-steps of

planning, conducting and evaluating results of matrix experiments to determine the best

levels of control factors. The primary goal is to keep the variance in the output very low

even in the presence of noise inputs. Thus, the processes or products are made robust

against all variations.

A metal lathe or metalworking lathe is a large class of lathes designed for precisely

machining relatively hard materials. They were originally designed to machine metals;

however, with the advent of plastics and other materials, and with their inherent

versatility, they are used in a wide range of applications, and a broad range of materials.

In machining jargon, where the larger context is already understood, they are usually

simply called lathes, or else referred to by more-specific subtype names such as

toolroom lathe, turret lathe and etc. These rigid machine tools remove material from a

rotating workpiece via the movements of various cutting tools, such as tool bits and drill

bits.

3

Turning is one of the most commonly used processes where metal is removed by

rotating the wokpiece with respect to a tool. The workpiece is held in a chuck that is

clamped to the spindle. The tool is held in a tool post that is mounted on a cross slide,

which provides radial tool movement. If the workpiece is long, both of the ends are held

by the chuck and tailstock. The cross-slide is held on the top of a carriage that has

motion along the axis between spindle and tailstock centers. Conventional lathes have

single motor that rotates the spindle via gearbox and belts (Figure 1.1).

Figure 1.1: Conventional lathe (Bulent, 2002)

CNC is the process of manufacturing machined parts. Numerical Control (NC) is the

original name given to this technology and is still often used interchangeably with CNC.

NC technology has been one of manufacturing's major developments in the past fifty

years. It not only resulted in the development of new manufacturing techniques and the

achievement of higher production levels, but it also helped increase product quality and

stabilize manufacturing costs (Ismail, 2002).

4

Due to the increasing demand of precision parts and devices in many industries such as

optics, computers, automotive and aerospace etc, it may, in general, be possible to

achieve the required precision operations at high accuracy by using expensive

manufacturing equipments. In addition to these costly equipments, using a secondary

finishing operation such as grinding or polishing may significantly reduce the

productivity and introduce set-up errors. There are some ultra precise turning machines,

which can produce parts at micro level accuracy. Special machine tool manufacturers

produce these machines. But they are very costly compared to standard machine tools

used in the industry. These turning machines have to be operated in a temperature

controlled, vibration free and stable environment.

In CNC (Computer Numerical Control) turning machines, unlike conventional ones, the

feed and spindle speeds are programmed within computer programs (Figure 1.2). In

these machines, the turret holds the tools. The turret may contain multiple 6 until 12

cutting tools.

Figure 1.2: CNC turning machine (Bulent, 2002)

5

CNC lathes are rapidly replacing the older production lathes due to their ease of setting

and operation. They are designed to use modern carbide tooling and fully utilize modern

processes. The part may be designed and the toolpaths programmed by the CAD/CAM

process, and the resulting file uploaded to the machine, and once set and trialled the

machine will continue to turn out parts under the occasional supervision of an operator.

The machine is controlled electronically via a computer menu style interface, the

program may be modified and displayed at the machine, along with a simulated view of

the process. The setter needs a high level of skill to perform the process, however the

knowledge base is broader compared to the older production machines where intimate

knowledge of each machine was considered essential. These machines are often set and

operated by the same person, where the operator will supervise a small number of

machines. The design of a CNC lathe has evolved yet again however the basic principles

and parts are still recognizable, the turret holds the tools and indexes them as needed.

The machines are often totally enclosed, due in large part to Occupational health and

safety (OH&S) issues.

Since the introduction of the first NC machine, there have been many applications of NC

machining technology such as, turning, grinding, drilling, flame and laser cutting,

forming and bending, punching and nibbling, electric discharge machining. In NC there

are many sources and look-up tables available for selecting these correct parameters. For

turning, the diameter of the workpiece and the surface feet per minute for the material

are factors in determining the proper speeds and feed rates (Ismail, 2002).

The important parameters of turning machines are spindle speed, feed rate, depth of cut

and tool geometry such as rake face and clearance face. Spindle speed is the angular

speed of the rotating workpiece. Feed rate is the distance moved by the tool in an axial

direction for each revolution of the workpiece. Depth of cut is the thickness of metal

removed from the workpiece measured in a radial direction.

6

The present work concerns with the optimization of the machining parameters in CNC-

Turning machine, and study their effects on the surface roughness of mild steel

workpiece. The evaluations are defined from the experiments outcomes. All the findings

from this study will prove which parameters between cutting speed, feed rate and depth

of cut will give most effect to the surface roughness of mild steel using carbide cutting

tool especially in CNC turning machine.

1.2 Problem Statement

Currently in CNC turning operation, there are a few conditions of part after machining.

The conditions of the part are recognized by referring the accuracy of the dimension and

surface roughness. The good surface roughness is caused by many variables. It might be

cutting speed, feed rate or depth of cut. Hence, it is important to know suitable feed rate,

cutting speed and depth of cut in order to get fine surface roughness. For this project, the

main effects of machining parameters that will be analyze are feed rate, cutting speed

and depth of cut while machining process towards surface roughness. After machining

process, the surface roughness shall gives results depending on several of feed rate,

cutting speed and depth of cut used. Type of material used was mild steel and in order to

investigate the effect of those variables, an analysis will be carry out with help of the

previous study on the literature review on investigations into the effect of cutting

parameters on surface roughness in CNC turning machine.

7

1.3 Objective of Project

The purposes of this project are:

1. To analyze the effects of feed rate, cutting speed and depth of cut on machining

mild steel using carbide cutting tools.

2. To determine CNC Lathe Turning optimum parameters setting for machining

mild steel by utilization of Taguchi Method.

1.4 Scope of Project

This research investigate and analyze the relationship between surface roughness and

machining parameter like feed rate, cutting speed and depth of cut in turning operation.

Carbide cutting tool and mild steel will be use throughout this experiment. During this

machining process, the machining parameters are set to 3 different values. Taguchi

method was used as a tool to analyze and give the number of parameter that was run in

this study. However, there are few things that will not be taken in consideration such as

the cycle time which is the time taken in order to finish a product, the type of coolant

that will be use in the experiment and the capability of the carbide cutting tool to

produce the product. It is important to note that the mathematical modeling for this

study will not provided and it was out of the scope. The experiment will be done using

HAAS CNC turning machine. Each samples then planned to be analyzed using Surface

Roughness Tester, SJ-301 at the UTeM Metrology Lab.

8

1.5 Report Outline

This report writing consists of six chapters. Chapters 1 describes about the introduction,

which are include the background, problem statement, objectives, scope, and importance

of the study. In the other hand, chapter 2 stressed on the literature review of related

issues and chapter 3 highlighted more towards the methodology of the project, which is

include the process planning, flowchart, data gathering method and analytical technique

in the project. Chapter 4 is result analysis for experiment that will be done, while chapter

5 is consist discussion by refer to the result. Lastly, chapter 6 states the conclusion and

recommendations to improve the experiment for next time.

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

Legend Indicator Planning Actual

14 Complete the report and submit to supervisor

15 Preparation for oral presentation

16 Presentation PSM 1

First draft submission

8

9

Make flow chart for methodology

5

Writing up: Introduction

6

Writing up: Literature Review7

Meet and discuss the progress of PSM with supervisor

2 Making planning progress by Gantt Chart

3 Discuss the objectives and scopes with supervisor

4

Find all informations, journal and references book

Gantt Chart PSM 1

No. Task Week

1 Confirm project title and supervisor

1.6 Gantt Chart

Table 1.1: Gantt Chart for PSM 1