Investigate Surface Integrity When Machining FC300 Cast Iron Using Uncoated Carbide Ball End Mill : Study Of Surface Profile.

INVESTIGATE SURFACE INTEGRITY WHEN MACHINING

FC300 CAST IRON USING UNCOATED CARBIDE BALL

END MILL: STUDY OF SURFACE PROFILE

MOHD FIZREE BIN ZAINAL ABIDIN

B051010037

UNIVERSITI TEKNIKAL MALAYSIA MELAKA 2013

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

INVESTIGATE SURFACE INTEGRITY WHEN MACHINING

FC300 CAST IRON USING UNCOATED CARBIDE BALL END

MILL: STUDY OF SURFACE PROFILE

This report submitted in accordance with requirement of the Universiti Teknikal Malaysia Melaka (UTeM) for the Bachelor Degree of Manufacturing Engineering

(Manufacturing Process) (Hons.)

by

MOHD FIZREE BIN ZAINAL ABIDIN B051010037

880823 – 56 – 6899

FACULTY OF MANUFACTURING ENGINEERING 2013

UNIVERSITI TEKNIKAL MALAYSIA MELAKA

BORANG PENGESAHAN STATUS LAPORAN PROJEK SARJANA MUDA

TAJUK: Investigate Surface Integrity When Machining FC300 Cast Iron Using Uncoated Carbide Ball End Mill: Study Of Surface Profile

SESI PENGAJIAN: 2012/13 Semester 2

Saya MOHD FIZREE BIN ZAINAL ABIDIN

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 sebagaimana yang termaktub dalam AKTA RAHSIA RASMI 1972)

(Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi/badan di mana penyelidikan dijalankan)

Alamat Tetap:

No 25 Jln Pinggiran 3/7,

Pinggiran Batu Caves,

68100 Batu Caves, SELANGOR.

Disahkan oleh:

DECLARATION

I hereby, declared this report entitled “Investigate Surface Integrity When Machining FC300 Cast Iron Using Uncoated Carbide Ball End Mill: Study of Surface Profile” is the

results of my own research except as cited in references.

Signature :

Author’s Name : Mohd Fizree Bin Zainal Abidin

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) (Hons.). The member of the supervisory committee is as follow:

ABSTRAK

Tujuan kajian ini adalah untuk mendapatkan parameter yang optimum untuk pemesinan FC300 ‘cast iron’ dalam konteks kekasaran permukaan dan tekstur permukaan. FC300 ‘cast iron’ merupakan satu bahan yang selalu digunakan didalam industri pembuatan acuan. Parameter yang akan dinilai berdasarkan 6000 - 9000 rpm kelajuan pemutaran, 4 - 7 m/min kadar suapan dan dengan nilai yang sama untuk pemotongan dalaman sebanyak 0.01mm. Didalam kajian ini, pemesinan dijalankan menggunakan mesin ‘milling’ didalam keadaan kering dan alat pemotongan yang akan digunakan ialah ‘uncoated carbide ball end mill’ dengan diameter 32mm. Prestasi integriti permukaan FC300 ‘cast iron’ akan diambil kira oleh mesin kekasaran permukaan dan mesin permukaan profil dengan menggunakan ‘Scanning Electron Microscope’ (SEM). ‘Response Surface Methodology’ (RSM) telah digunakan untuk mengkaji optimum parameter pemotongan di dalam konteks untuk mendapatkan permukaan yang baik. Kajian ini akan menyediakan maklumat yang berguna tentang parameter pemotongan yang sesuai untuk FC300 ‘cast iron’ dengan cekap.

ABSTRACT

The aim of this research is to obtain the optimal parameters for machining FC300 cast iron interns of surface roughness and surface texture. FC300 is a material that frequently used in die industry. The parameters that will be evaluated are based on the 6000 – 9000 rpm spindle speed, 4 – 7 m/min feed rate and with constant depth of cut 0.01mm. In this research, the machining conducted by using CNC milling machine under dry condition and the cutting tool that will be used is uncoated carbide ball end mill with diameter 32mm. The performance of surface integrity for FC300 cast iron will be measure by surface roughness machine and surface profile using Scanning Electron Microscope (SEM). Response Surface Methodology (RSM) was used to evaluate the optimum cutting parameter in order to obtain a better surface finish. This research will provide useful information about the suitable cutting parameter to machining FC300 cast iron efficiently.

DEDICATION

For my beloved parents, who always encourage and give all the support that I really need during accomplish this thesis.

ACKNOWLEDGEMENT

Bissmillahirrahmanirrahim,

Alhamdulillah. Thanks to Allah SWT, whom with His willing giving me the opportunity to complete this Final Year Project. This Final Year Project was prepared for Faculty of Manufacturing Engineering Universiti Teknikal Malaysia Melaka (UTeM) basically for student in fourth year to complete the undergraduate program that leads to the degree of Bachelor of Engineering in Manufacturing. This report is based on the methods given by the university

Firstly, I would like to express my deepest thanks to, Dr. Mohd Hadzley Bin Abu Bakar, as my Supervisor for this Final Year Project, who had guided me and give valuable information and suggestion during completion for this Final Year Project. I also want to thanks all staff at Universiti Teknikal Malaysia Melaka (UTeM) for their cooperation to lead me in this Final Year Project.

Deepest thanks and appreciation to my parents, family, special mate of mine, and others for their cooperation, encouragement, constructive suggestion and full of support for the report completion, from the beginning till the end. Also thanks to all of my friends and everyone, that has been contributed by supporting my work and helps myself during this Final Year Project.

TABLE OF CONTENT

Abstrak i

Abstract ii

Dedication iii

Acknowledgement iv

Table of Content v

List of Table viii

List of Figure ix

List of Abbreviations xi

CHAPTER 1: INTDOCUTION 1

1.0 Introduction 1

1.1 Objective 3

1.2 Problem Statement 4

CHAPTER 2: LITERATURE REVIEW 5

2.1 Machining 5

2.1.1 Factor That Influence Machining 7

2.1.2 Milling 9

2.1.2.1 Type of Milling Machine 10

2.1.2.2 Equipment for Milling Machine 12

2.1.2.3 Milling Operation 13

2.1.2.4 Feature of Milling Tool 15

2.1.2.5 Type of Milling Tool 17

2.2 Cast Iron 19

2.2.1 History of Cast Iron 19

2.2.2 Production of Cast Iron 20

2.2.3.1 Tensile Strength 20 2.2.3.2 High Compressive Strength 21

2.2.3.3 Low Melting Point 21

2.2.3.4 Resistance to Deformation 21

2.2.3.5 Resistance to Oxidation 21

2.2.4 Class of Cast Iron 22

2.2.4.1 Gray Cast Iron 22

2.2.4.2 White Cast Iron 23

2.2.4.3 Ductile Cast Iron 24

2.2.4.4 Malleable Cast Iron 25

2.2.4.5 Compacted Graphite Iron 26

2.2.5 FC300 Cast Iron 26

2.2.5.1 FC300 Composition 27

2.3 Surface Integrity 27

2.3.1 Surface Roughness 28

2.3.2 Surface Defect 29

2.4 Cutting Tool 33

2.4.1 General Characteristic of Cutting tool Material 36

CHAPTER 3: METHODOLOGY 42

3.1 Introduction 42

3.2 Flow Chart 43

3.3 Work Material 44

3.4 Cutting Tool 45

3.5 Machining and Cutting 47

3.5.1 Machine Experiment 47

3.5.2 Cutting Parameter 48

3.6 Performance Measure 48

3.6.1 Surface Roughness Tester 48

3.6.2 Surface Profile (SEM) 49

CHAPTER 4: RESULTS AND ANALYSIS 53

4.1 Surface Roughness, Ra 53

4.1.1 Optimization Surface Roughness 59

4.2 Surface Profile 63

4.2.1 Surface Profile for Each Cutting Parameter 65

CHAPTER 5: CONCLUSION AND RECOMMENDATION 68

5.1 Conclusion 68

5.2 Recommendation 70

LIST OF TABLE

2.1 Different Between Orthogonal and Oblique Machining 6

2.2 Factors Influence Machine Operation 8

2.3 Equipment for Milling Machine 12

2.4 Milling Operation 13

2.5 Feature of Milling 15

2.6 Milling Cutter 17

2.7 Range of Composition for Cast Iron 22

2.8 General composition FC300 27

2.9 General Characteristic of Cutting Tools 36

3.1 Chemical Composition of FC300 Cast Iron 44 3.2 Specification Parameter of Ball End Mill Hitachi ABPF-32MT4 45

3.3 Experiment Procedure 50

4.1 Results for Surface Roughness for Each Parameter and Average 53 4.2 ANOVA Table for Response Surface Cubic Model 55

LIST OF FIGURE

2.1 Orthogonal Machining and Oblique Machining 6

2.2 Milling Machine 9

2.3 Column and Knee Type Milling Machine 10

2.4 Bed Type Milling Machine 11

2.5 CNC Milling Machine 11

2.6 Diagram of an End Mill Cutting Tool 16

2.7 Metal Alloy Classification 19

2.8 Microstructure for Gray Cast Irons with Graphite Flakes 23

2.9 Microstructure for White Cast Iron 24

2.10 Microstructure for Ferrictic Ductile Cast Iron 24 2.11 Microstructure for Pearlitic Malleable Ductile Cast Iron 25 2.12 Coordinate uses for surface roughness measurement 29 2.13 Standard Terminology and Symbols to Describe Surface Finish 29

2.14 Cracks 30

2.15 Craters 30

2.16 The Interaction between Heat Source and the Base Metal 31

2.17 Intergranular Attack 31

2.18 Pits 32

2.19 Single Point Cutting Tool for Turning Application 33

2.20 Multipoint Cutting Tool 34

2.21 The Hardness of Various Cutting Tool Materials 35 2.22 Mechanical Properties for Groups of Tool Materials 36

3.1 Research Methodology 43

3.2 The Main Grey Cast Iron Grades Worldwide 44 3.3 Ball End Mill 32mm (Hitachi ABPF-32 MT4) 45

3.5 Specifictaion Parameter of Insert SRFT 30 VP15TF 46

3.6 DMF 250 Linear Deckel Maho 47

3.7 Surface Roughness Tester 48

3.8 Scanning Electron Microscope 49

4.1 Annova Evaluation Graph 56

4.2 Comparison between Actual Values and Calculated Value 58

4.3 Influence of Spindle Speed over Ra 59

4.4 Influence of Feed Rate over Ra 60

4.5 Response Surface Interaction between Spindle Speed and Feed Rate 61 4.6 Contour of Minimum Region of Surface Roughness 62 4.7 Porosity Occur at Surface FC300 Cast Iron 63

4.8 Propagation of Crack 64

4.9 Flaking at Surface FC300 Cast Iron 64

LIST OF ABBREVIATIONS

Anova - Analysis of Variance Cbn - Cubic Boron Nitride

CNC - Computer Numerical Method EDM - Electric Discharge Machine HSM - High Speed Machine HSS - High Speed Spindle MMSB - Miyazu Malaysia Sdn Bhd MRR - Material Removal Rate Ra - Arithmetic Average

SEM - Scanning Electron Microscope Rpm - Revolution per Minute

CHAPTER 1

INTRODUCTION

1.0 Introduction

The manufacturing process of stamping die is one of the most demanding tasks in manufacturing engineering. The stamping die must have a high material hardness (good impact resistance), not easily deformed under certain temperature and the most important thing have a short lead time in order to manufacture the die. At the same time, cost to make the stamping die must be the cheapest price as well as emphasizing the maximum possible level of quality, because quality requirements become more and more important due to competition and quality awareness. In Malaysia, one of the associated companies in the stamping die manufacturing is Miyazu Malaysia Sdn Bhd (MMSB). MMBS was established in 1991 and is one company known for specializing in manufacture of stamping die, particularly in processing automotive body part. Example of die automotive body part supplies by MMBS are for Proton, Perodua, Honda, Isuzu, Lotus, Nissan, Mazda, Peugeot, Subaru and Toyota.

There are a lot of materials that used to produce a stamping die for manufacturing applications; one of the examples is cast iron. The term cast iron refers to a family of ferrous alloys composed of iron, carbon (ranging from 2.11 % to about 4.5%), and silicon (up to about 3.5 %) [Kalpakjian (2010)]. This material has high carbon content makes it easily to cast into a complex shape and machined, excellent wear resistance and high hardness. The melting point of this material is between 1147 - 1250°C, which is substantially lower than the melting point for mild steel [Srivastava

(2011)]. In this research, the grade of cast iron is FC300 in the Japanese Industrial standard (JIS G5501) code will be use. The mechanical properties of the FC300 cast iron are depending on the metal matrix as well as on the format and quantity of the graphite. On the other hand, FC300 cast iron with totally pearlitic structure provides more mechanical properties, a good surface finish and higher hardness. Another important characteristic for FC300 cast iron is good leaking resistance, because its properties can accommodate to a high pressure and usually been used in production of valve bodies, heads, caps and plungers. FC300 cast iron specification is similar to ASTM A48, class 40 [Fujii (2009)].

In machining stamping die, one of the important characteristic is ‘Surface Integrity’. Surface integrity is an important consideration in stamping die manufacturing, because it influences such properties as fatigue strength and they control the strength and performance of structural components [Kalpakjian (2010)]. In other words, stamping die must be free from scratch, pores, pitting, pin hole and etc, because fine surface finish is essential not only to provide accurate and stringent tolerance for complex stamping product but also provide optimum heat transfer during quenching process. In order to get a better surface integrity at stamping die, the stamping die will be machining at High Speed Machining (HSM) and then is polished manually in order to get good surface finish and texture.

The focus of this study is to analyze what is the optimum cutting parameter for FC300 cast iron by using High Speed Machining to get a fine surface integrity for stamping die application. This study will be cover cutting speed (v) from 6000rpm to 9000 rpm and feed rates (f) from 4 m/min to 7 m/min for cutting parameter. The works will be carried out in close cooperation with the Miyazu Malaysia Sdn. Bhd (MMBS). Results that gain from this analysis will provide useful information about what is the best cutting parameter to manufacture one stamping die, in order to get a good surface finish and texture without no need anymore manual polishing. The data obtained also will be useful as reference materials for machinist in planning their machining in order to produce maximize surface quality, reduce processing steps and hence minimize operational cost.

1.1 Objective

The overall aim of the research is to study the optimum parameter for machining FC300 cast iron. The aim can be resolved into the following specific objectives:

a) To evaluate the optimum cutting speed and feed rates when machining FC300 cast iron based on surface roughness.

b) To analyze the effect of cutting parameter interaction on surface roughness during machining of FC300 cast iron.

c) To analyze the surface integrity using the different cutting parameter during machining FC300 cast iron.

1.2 Problem Statement

Process for manufacturing die requires a several step in order to make it. The first step is rough machining, where the workpiece material is removed as quickly as possible. The second step is semi finishing, where machining is carried out to ensure consistent material removal rate and the lastly is polishing. Generally, this entire step requires a long lead time and requires a lot of skilled workers. In Miyazu Malaysia Sdn Bhd, all die that was made is machining by using one cutting parameter, which are cutting speed at 6000rpm and feed rates is 5.5m/min. After semi finishing, MMSB was hiring a three worker to polish the dies manually until the die surface produce a good surface. In this cases, MMSB found that the process polishing have some problem such as a human error where the polishing not consistence at all side.

Besides require a long lead time in the die manufacturing process. Workers that assigned to do polishing the die show a situation that is not ergonomic, where workers have to bend its body while this polish process take place. This will give ergonomic hazard to the worker, if this type of work is continuous and better ergonomic process is not taken into account. Ergonomics it is important because it studies and finds ways to make workers more comfortable and satisfied. With proper use, absences are decrease and productivity will increase and can give a lot of benefit to organization and human.

Therefore, this research is done to get the optimization cutting parameters for MMSB and indirectly will get a good surface finish and texture. Thus, the time required to polish the die after machining will reduce if surface of the die is not too very rough, and at the same time will reduce the cost of manufacturing die, because polishing process gives high costs as its vulnerable to human error.

CHAPTER 2

LITERATURE REVIEW

2.1 Machining

Machining is a term used to describe a variety of material removal processes in which a cutting tool removes unwanted material from a workpiece to produce the desired shape. The workpiece is typically cut from a larger piece of stock, which is available in a variety of standard shapes, such as flat sheets, solid bars, hollow tubes, and shaped beams [Kadirgama (2009)]. Machining also covers several processes, which can be divided into the following categories [Madraj (2001)]:

a) Abrasive processes - material removal by hand, abrasive particles, example grinding.

b) Nontraditional processes - various energy forms other than sharp cutting tool to remove material.

c) Advanced machining processes - utilize electrical, chemical, thermal, and hydrodynamic methods, as well as lasers.

d) Cutting - involves single point or multipoint cutting tools with a clearly defined tool shape.

On the basic of the angular relationship between the cutting velocity vector and the cutting edge of the tool, different metal cutting process can be classified into two broad categories, which is (i) orthogonal cutting and (ii) oblique cutting as show at

Figure 2.1. In orthogonal cutting, the cutting edge of the tool is perpendicular to the cutting speed direction [Junega and Sekhon (2003)]. The process of orthogonal cutting is the tool is pushed into the workpiece, a layer of material is removed from the workpiece and it slides over the front face of the tool called rake face. When the cutting edge of wedge is perpendicular to the cutting velocity, the process is called orthogonal cutting. Meanwhile in oblique cutting, the angle between the cutting edge and cutting velocity is different from 90° and the cutting edge of the tool is not perpendicular to the cutting velocity but set at angle with the normal to the cutting velocity [Rajput (2007)]. The different between orthogonal and oblique cutting is show at Table 2.1.

(a) (b)

Figure 2.1: (a) Orthogonal Machining (b) Oblique Machining [Rajput (2007)].

Table 2.1: Different Between Orthogonal and Oblique Machining [Rajput (2007)].

No Aspects Orthogonal Cutting Oblique Cutting

1 Inclination of the cutting edge of the tool.

Perpendicular to the direction of tool travel.

Inclined at an angle with the normal to the direction of tool travel. 2 Clearance of the

workpiece width by the cutting edge.

The cutting edge clears the width of the workpiece on either ends

The cutting edge may or may not clear the width of the workpiece.

3 The chip movement. The chip flows over the tool face and direction of chip flow velocity is normal to the cutting edge. The chip coils in a tight flat spiral.

The chip flow on the tool face making an angle with the normal on the cutting edge. The chip flows sideways in a long curl.

4 Number of components of cutting force acting on the tool.

Only two components of the cutting force act on the tool. These two components are perpendicular to each other and can be represented in a plane.

Three components of the force act at the cutting edge.

5 Maximum chip

thickness occurrence.

Maximum chip thickness occurs at its middle.

The maximum chip thickness may not occur at middle.

6 Tool life. Less More.

2.1.1 Factor That Influence Machining

There are many factors that can influence machining operation (Table 2.2); it can be classified into two sections which is independent variable and dependent variable [Kalpakjian (2010)]. Meaning for independent variable is variable that can control and choose in cutting process, example:

a) Tool material and coatings

b) Tool shape, surface finish and sharpness c) Workpiece material and condition d) Cutting speed, feed and depth of cut e) Cutting fluid

f) Characteristic of the machine tool g) Workholding and fixturing

Dependent variable in cutting is those that are influenced by changes in the independent variable listed above and include:

a) Type of chip produced

b) Force and energy dissipated during cutting

c) Temperature rise in the workpiece, the tool and the chip d) Tool wear and failure

e) Surface finish and surface integrity of the workpiece

Table 2.2: Factors Influence Machine Operation [Kalpakjian (2010)].

Parameter Influence and interrelationship

Cutting speed, depth of cut, feed and cutting fluid.

Forces, power, temperature rise, tool life, type of chip, surface finish and integrity. Tool angles As above, influence on chip flow direction,

resistance to tool wear and chipping.

Continuous chip Good surface finish, steady cutting force, undesirable especially in automated machinery.

Built up edge chip Poor surface finish and integrity; if thin and stable, edge can protect tool surfaces. Discontinuous chip Desirable for ease of chip disposal;

fluctuating cutting forces; can affect surface finish and cause vibration and chatter.

Temperature rise Influences tool life, particularly crater wear and dimensional accuracy of workpiece; may cause thermal damage to workpiece

1.1 Objective

The overall aim of the research is to study the optimum parameter for machining FC300 cast iron. The aim can be resolved into the following specific objectives:

a) To evaluate the optimum cutting speed and feed rates when machining FC300 cast iron based on surface roughness.

b) To analyze the effect of cutting parameter interaction on surface roughness during machining of FC300 cast iron.

c) To analyze the surface integrity using the different cutting parameter during machining FC300 cast iron.

1.2 Problem Statement

Process for manufacturing die requires a several step in order to make it. The first step is rough machining, where the workpiece material is removed as quickly as possible. The second step is semi finishing, where machining is carried out to ensure consistent material removal rate and the lastly is polishing. Generally, this entire step requires a long lead time and requires a lot of skilled workers. In Miyazu Malaysia Sdn Bhd, all die that was made is machining by using one cutting parameter, which are cutting speed at 6000rpm and feed rates is 5.5m/min. After semi finishing, MMSB was hiring a three worker to polish the dies manually until the die surface produce a good surface. In this cases, MMSB found that the process polishing have some problem such as a human error where the polishing not consistence at all side.

Besides require a long lead time in the die manufacturing process. Workers that assigned to do polishing the die show a situation that is not ergonomic, where workers have to bend its body while this polish process take place. This will give ergonomic hazard to the worker, if this type of work is continuous and better ergonomic process is not taken into account. Ergonomics it is important because it studies and finds ways to make workers more comfortable and satisfied. With proper use, absences are decrease and productivity will increase and can give a lot of benefit to organization and human.

Therefore, this research is done to get the optimization cutting parameters for MMSB and indirectly will get a good surface finish and texture. Thus, the time required to polish the die after machining will reduce if surface of the die is not too very rough, and at the same time will reduce the cost of manufacturing die, because polishing process gives high costs as its vulnerable to human error.

CHAPTER 2

LITERATURE REVIEW

2.1 Machining

Machining is a term used to describe a variety of material removal processes in which a cutting tool removes unwanted material from a workpiece to produce the desired shape. The workpiece is typically cut from a larger piece of stock, which is available in a variety of standard shapes, such as flat sheets, solid bars, hollow tubes, and shaped beams [Kadirgama (2009)]. Machining also covers several processes, which can be divided into the following categories [Madraj (2001)]:

a) Abrasive processes - material removal by hand, abrasive particles, example grinding.

b) Nontraditional processes - various energy forms other than sharp cutting tool to remove material.

c) Advanced machining processes - utilize electrical, chemical, thermal, and hydrodynamic methods, as well as lasers.

d) Cutting - involves single point or multipoint cutting tools with a clearly defined tool shape.

On the basic of the angular relationship between the cutting velocity vector and the cutting edge of the tool, different metal cutting process can be classified into two broad categories, which is (i) orthogonal cutting and (ii) oblique cutting as show at

Figure 2.1. In orthogonal cutting, the cutting edge of the tool is perpendicular to the cutting speed direction [Junega and Sekhon (2003)]. The process of orthogonal cutting is the tool is pushed into the workpiece, a layer of material is removed from the workpiece and it slides over the front face of the tool called rake face. When the cutting edge of wedge is perpendicular to the cutting velocity, the process is called orthogonal cutting. Meanwhile in oblique cutting, the angle between the cutting edge and cutting velocity is different from 90° and the cutting edge of the tool is not perpendicular to the cutting velocity but set at angle with the normal to the cutting velocity [Rajput (2007)]. The different between orthogonal and oblique cutting is show at Table 2.1.

(a) (b)

Figure 2.1: (a) Orthogonal Machining (b) Oblique Machining [Rajput (2007)].

Table 2.1: Different Between Orthogonal and Oblique Machining [Rajput (2007)].

No Aspects Orthogonal Cutting Oblique Cutting

1 Inclination of the cutting edge of the tool.

Perpendicular to the direction of tool travel.

Inclined at an angle with the normal to the direction of tool travel. 2 Clearance of the

workpiece width by the cutting edge.

The cutting edge clears the width of the workpiece on either ends

The cutting edge may or may not clear the width of the workpiece.

3 The chip movement. The chip flows over the tool face and direction of chip flow velocity is normal to the cutting edge. The chip coils in a tight flat spiral.

The chip flow on the tool face making an angle with the normal on the cutting edge. The chip flows sideways in a long curl.

4 Number of components of cutting force acting on the tool.

Only two components of the cutting force act on the tool. These two components are perpendicular to each other and can be represented in a plane.

Three components of the force act at the cutting edge.

5 Maximum chip

thickness occurrence.

Maximum chip thickness occurs at its middle.

The maximum chip thickness may not occur at middle.

6 Tool life. Less More.

2.1.1 Factor That Influence Machining

There are many factors that can influence machining operation (Table 2.2); it can be classified into two sections which is independent variable and dependent variable [Kalpakjian (2010)]. Meaning for independent variable is variable that can control and choose in cutting process, example:

a) Tool material and coatings

b) Tool shape, surface finish and sharpness c) Workpiece material and condition d) Cutting speed, feed and depth of cut e) Cutting fluid

f) Characteristic of the machine tool g) Workholding and fixturing

Dependent variable in cutting is those that are influenced by changes in the independent variable listed above and include:

a) Type of chip produced

b) Force and energy dissipated during cutting

c) Temperature rise in the workpiece, the tool and the chip d) Tool wear and failure

e) Surface finish and surface integrity of the workpiece

Table 2.2: Factors Influence Machine Operation [Kalpakjian (2010)].

Parameter Influence and interrelationship

Cutting speed, depth of cut, feed and cutting fluid.

Forces, power, temperature rise, tool life, type of chip, surface finish and integrity. Tool angles As above, influence on chip flow direction,

resistance to tool wear and chipping.

Continuous chip Good surface finish, steady cutting force, undesirable especially in automated machinery.

Built up edge chip Poor surface finish and integrity; if thin and stable, edge can protect tool surfaces. Discontinuous chip Desirable for ease of chip disposal;

fluctuating cutting forces; can affect surface finish and cause vibration and chatter.

Temperature rise Influences tool life, particularly crater wear and dimensional accuracy of workpiece; may cause thermal damage to workpiece