Effect Of Tool Geometry, Material Hardness And Cutting Parameters On The Cutting Force Turning Process

I admit that I have read this report and in my opinion this report is sufficient from the perspective of the scope and quality for awarding purposes Bachelor of Mechanical Engineering (Them1al Fluid)

Signature

Supervisor ame Date

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EFFECT OF TOOL GEOMETRY, MATERIAL HARDr ESS AND CUTTf.\JG

PARAMETERS ON THE CUTTING FORCE FOR TUR ING PROCESS

MOHAMAD SAIFUL AZHAR BIN HARUN

This report submitted to Faculty of Mechanical Engineering in fulfillment of the requirements for the award of the Bachelor of Mechanical Engineering

(Thermal-Fluids)

F acuity of Mechanical Engineering Kolej Universiti Teknikal Kebangsaan Malaysia

DECLARATION

" I hereby, declare that the work in tills report entitled "EFFECT OF TOOL GEOMETRY, MATERIAL HARDNESS A TD CUTTING PARAMETERS ON

THE CUTTING FORCE FOR TURNING PROCESS" is my own except for quotations and summaries which have been duly acknowledged "

11

Signature Author Date

Ill

DEDICATION

Dedicated to my beloved parents and my sisters ... . For understanding and moral support

IV

ACKNOWLEDGMENTS

Firstly, I would like to take this opportunity to express my deepest gratitude to my project supervisor, Mr. Mohd 1zam Bin Sudin from the Faculty of Mechanical Engineering, Kolej Universiti Teknikal Kebangsaan Malaysia (KUTKM), for his support, confidence, and guidance towards completing this project.

I would like to express greatest thankfulness to Mr. Abd Halim Bin Kling Head of Department, Germany Malaysian Institute (GMI), who has given advice and suggestion that contributed into the aspect of metal cutting characterization throughout the completion of this project.

v

ABSTRACT

In this experiment, effect of tool geometries, material hardness, feed rate, and

cutting speed on cutting forces were experimentally investigated. High speed steel

(HSS) tool blank with three type of geometries was prepared and mild steel CF1018

and DF2 steel bars were used as workpiece. Effect of tool geometries material

hardness and cutting parameters on cutting forces statistical analysis of variance was

performance. During the experiments two component of tool of tool force and tool

life of cutting tool were measured. This experiment shows that the effect of tool wear

was influenced to increase the cutting force. Different of tool geometries were

showed the variance was performance on cutting force. Where sharp edge show

lower tangential force on CF1018. The contact between lmm radius (nose radius)

and workpiece had been small impact on cutting force. But honed radius always high

tangential force on CFl 018 remarkably influence to material hardness also cutting

force. However material hardness is a one of the factors of increased cutting force

and tool life. Therefore, the resulted obtained from the analysis technique indicated

that the longer the cutting tools were in contact with the workpiece, the higher the

VI

ABSTRAK

Didalam projek akhir ini, kesan terhadap rekabentuk mata alat dan kekerasan

bahan kerja, kadar masukan dan kelajaun pemotongan didalam proses pemotongan

secara ujikaji diselidik. Dengan menggunakan mara alat yang belum diasah (tool

blank) jenis keluli berkelajuan tinggi (HSS) dengan tiga jenis rekabentuk mata alat

disediakan dan dua jenis bahan kerja yang berlainan kekerasanya iaitu keluli lembut

(mild steel) CFl 018 dan DF2. Kesan rekabentuk mata alat dan kekerasan bahan kerja

terhadap daya pemotongan secara statik dianalysis. Semasa ujikaji dijalankan dua

komponan daya pemotongan, janka hayat mata alat serta kehausan mata alat diukur.

Ujikaji ini menunjukan kesan kahuasan mata alat telah mempengaruhi peningkatan

kepada daya pemotongan. Rekabentuk mata aJat yang berbeza telah menunjukan

kepelbagaian daya didalam daya pemotongan. Dimana tepi mata alat tajam

menunjukan daya pemotongan menegak adalah rendah terhadap CFl 018. Hubungan

diantara I mm jejari hujung mata alat (nose radius) dan bahan kerja menghasilkan

kesan yang kecil terhadap daya pemotongan. Tetapi hujung mata alat bulat sentiasa

menunjukan nilai yang tinggi didalam daya pemotongan menegak CFl 018 yang

dikatakan mempengaruhi kepada kekersan bahan kerja serta daya pemotongan.

Narnun begitu kekerasan bahan kerja adalah salah satu faktor peningkatan daya

pemotongan dan janka hayat rnata alat. Oleh kerana itu keputusan yang diperolehi

menunjukan semakin panjang ternpoh penggunaan mata alat terhadap bahan kerja,

semakin tinggi kadar kehausan rnata alat. Persamaan Taylor yang diperolehi didalam

\II

TABLE OF CONTENT

DECLARATION ... ii

DEDICATION ... iii

ACJ<:NOWLEDGMENTS ... iv ABSTRACT ... v

ABSTRAK ... vi

TABLE OF CONTENT ... vii LIST OF FIGURE ... x

LIST OF TABLE ... xii

LIST OF APPENDIX ... xiii APPENDIX B ... xili NOMENCLATURE ... xiv INTRODUCTION ... ! 1.1 Background ... 1

1.2 Research Objective ... 2

1.3 Structure of the Project. ... 2

LITERATURE REVIEW ... 4

2.1 Introduction ... 4

2.2 Material Removal ... 6

2.3 Cutting Forces ... 6

2.4 Single Point Cutting Tool. ... 8

2.4.1 Rake Angle ... 9

2.4.2 1 egative Rake Angle ... 1 0 2.4.3 Positive rake angle ... 1 0 2.4.4 Neutral Rake ... 11

111

2.5.1 Flank Wear ... IS

2.5.2 Crater Wear ... l7

2.6 Surface Roughness ... 18

2.7 Cutting Temperature ... 18

2.8 Chip Removal. ... 19

METHODOLOGY ..................... 21

3.1 lntroduction ... 21

3.2 Background ... 21

3.3 Experiment Details ... , ... 22

3.3.1 Machining Parameters ... 25

3.3.2 Workpiece Material ... 26

3.3.3 Tool Geotnetry ....................... 26

3.4 Equipment Used ... 28

RESULT AND DISCUSSION .............. 31

4.1 Introduction ... 31

4.2 Result Experiment. ... 32

4.3 Depth of Cut Effect. ... 32

4.3.1 Effect of Depth-of-cut on tangential force ... 32

4.3.2 Effect Depth of Cut on Feed Force ... 35

4.4 Feed Rate Effect. ... 37

4.4.1 Effect Feed Rate on Tangential Force ... 37

4.4.2 Effect of feed Rate on Feed Force ... 39

4.5 Effect Cutting Speed . ............................ 41 4.5.1 Effect of Cutting Speed on Tangential Force ...... .41 4.5.2 Effect of Cutting Speed on Feed Rate ... .43

4.6 Effect of Material Hardness on Tangential and Feed Force ... .45

4.7 Tool Life ... 47

CONCLUSION AND RECOMENDATION ....................... 49

5.1 Conclusion ... 49

5.2 Recommendation ... 5!

IX

APPENDIX .................................................. SS

APPE ·oiX A ... 55

X

LIST OF FIGURE

Figure 2.1: Merchant's composite force circle in orthogonal cutting [Binu Paul John

(2003)] ... 7

Figure 2.2: Cutting tools terminology [www-me.mit.edu/machine tools] ... 8

Figure 2.3: Tegative Rake Angle ... 10

Figure 2.4: Positive Rake Angle ... 11

Figure 2.5: eutral Rake ... 11

Figure 2.6: Tool Wear Phenomena [Armarego and Brown, The Machining of Metals]. 12 Figure 2.7: Graph cutting speed versus time ... 13

Figure 2.8: Tool life curves for a variety of cutting tools material. ... 14

Figure 2.9: Flank Wear [Cutting Tool Application] ... 15

Figure 2.10: Variation of flank wear rate with cutting time ... 16

Figure 2.11: Crater Wear [Cutting Tool Application] ... 17

Figure 2.12: Variation of crater depth with time for different cutting speed V (M.C.Shaw) ... 17

Figure 2.13: Typical temperature distributions in the cutting zone [Cutting Tool Application] ... 19

Figure 2.14: Various types of chip formations [Cutting Tool Application]. ... 20

Figure 3.15: Position of dynamometer at Courtesy Dorian Tool ... 22

Figure 3.16: Tool axis with tail stock ... 23

Figure 3.17: Collect the data with using dynamometer ... 24

Figure 3.18: Schematic of orthogonal cutting condition ... 24

Figure 3.19: Material workpiece mild steel CFl 018 and mild steel DF2 ... 26

Figure 3.20: Tool geometry (a) Sharp edge, (b) ose radius and, (c) Honed radius ... 27

Figure 3.21: High Speed Steel (HSS) cutting tool blank ... 27

Figure 3.22: The lathe machine SM200X1500 ... 28

Figure 3.23: Dynamometer Fl300Z1 ... 29

XI

Figure 4.25: The effect of depth of cut on tangential force at material CFl 018 ... 33

Figure 4.26: The effect of depth of cut on tangential force at material DF2 ... 34

Figure 4.27: The effect of depth of cut on feed force at material CFI 018 ... 35

Figure 4.28: The effect of depth of cut on feed force at material DF2 ... 36

figure 4.29: The effect of feed rate on tangential force at material CF 1018 ... 3 7 Figure 4.30 The effect of fade rate on tangential force at material DF2 ... 38

Figure 4.31: The effect of feed rate on feed force at material CF 1018 ... 39

Figure 4.32: The effect of feed rate on feed force at material DF2 ... .40

Figure 4.33: The effect of cutting speed on tangential force at material CFl 018 ... .41

Figure 4.34: The effect of cutting speed on tangential force at material DF2 ... .42

Figure 4.35: The effect of cutting speed on feed rate at material CF1 018 ... 43

Figure 4.36: The effect of cutting speed on feed force at material DF2 ... 44

Figure 4.3 7: Effect of tool geometry and material hardness on tangential forces (feed rate= O.lmm/rev, Depth of cut =0.5 mrn and Cutting Speed= 40 m/min) ... .45

Figure 4.38 Effect of tool geometry and material hardness on Feed Force (Feed Rate = 0.1 mm/rev, Depth of Cut= 0.5 mm and Cutting Speed= 40m/rev) ... .46

Xll

LIST OF TABLE

Table 2.1: General Recommendations HSS Cutting Tool Angles [Manufacturing

Engineering and Technology] ... 9

Table 2.2: Recommended wear land size for different tool material and operations [Metal Cutting Theory and Practice (1997)]. ... 16 Table 3.3: Machining parameters used for the experiment and their values ... 25

Table 4.4: Cutting parameters for material mild steel CFI 018 ... 32

Table 4.5: Cutting parameters for material mild steel DF2 ... 34 Table 4.6: Cutting parameters for material mild steel CF1 018 ... 35

Table 4.7: Cutting parameters for material mild steel DF2 ... 36

Table4.8: Cutting parameters for material mild steel CF1018 ... 37

Table 4.9: Cutting parameters for material mild steel DF2 ... 38

Table 4.10: Cutting parameters for material mild steel CF 1018 ... 39

Table 4.11: Cutting parameters for material mild steel DF2 ... 40

Table 4.12: Cutting parameters for material mild steel CFl 018 ... 41

Table 4.13: Cutting parameters for material mild steel DF2 ... 42

Table 4.14: Cutting parameters for material mild steel CF 1018 ... .43

Table 4.15: Cutting parameters for material mild steel DF2 ... 44

Table 4.16: Tangential force for different tool geometry on material Hardness ... 45

Table 4.17 Feed Force for different tool geometry on material hardness ... 46

Table 4.18: Cutting Parameters for determined Flank Wear ... 47

XIII

LIST OF APPEJ\DIX

APPENDIX A

A- 1: Workpiece Before Machining ... 55

A-2 : Workpiece after machjning ... 55

A- 3 : Tool blank ... 56

A- 4 : Sharp Edge cutting tool ... 56

A- 5: Flank wear sharp edge CF1018 ... 57

A-6 : Crater wear at sharp edgee CF 10 18 ... 57

A-7: Crater wear at nose radius Cfl 018 ... 58

A-8: Chipping at nose radius Cfl 018 ... 58

A-9: Chipping at honed radius ... 59

A- 10 : Crater wear at nose radius DF2 ... 59

A- 11 : Fracture at honed radius ... 60

A- 12 : Notch wear at honed radius ... 60

APPENDIXB B- I: Mild steel CFI 018 (sharp edge) ... 61

B- 2: Mild Steel DF2 (sharp edge) ... 62

B-3: Mild Steel CF1018 (Nose Radius) ... 63

B- 4: Mild Steel DF2 ( ose Radius) ... 64

B-5 : Mild Steel CFl 018 (Honed Radius) ... 65

XIV

NOMENCLATURE

F Frictional force at tool-chip interface

Fe Cutting force

Ft Thrust force

Fn orrnal force

Fs Shear force

N Normal force at tool-chip interface

R Resultant cutting force

T Time

c

v

b Thickness

t Feed

lch Chip thickness

to Depth of cut

v Cutting speed

a Rake angle

fJ Friction angle

f1 Coefficient of friction

CHAPTER 1

INTRODUCTION

1.1 Background

Most of turning operation use single point cutting tool. The cutting tool is

blank or tool insert. Tool geometry is very important in machining operation. Rake

angle is one of the factors that influence in machining problem. In machining

process, cutting tool removes material from the surface of the workpiece. Therefore,

the selection of cutting tool material and workpiece is important to ensure the quality

of product to fulfill the standard on metal cutting. In this project turning process

parameter, tool geometry, material hardness, and cutting force were concentrating.

Another tool geometry of cutting tool is rake angles. The angles also

influence to control chip formation and strength of the cutting tool. Nevertheless,

positive and negative rake angle are usually used in cutting process. These two rakes

will effect to the cutting forces and chip formation.

In metal cutting, cutting force are importance criteria to be measured. Many

researchers concentrate on two dimensiona1 problems instead of three dimensional

cutting processes. Therefore, cutting force, Fe (horizontal) and trust forces, F1

(\·ertical) are determined in two dimensional cutting processes. Using 2-axis

mechanical dynamometer. cutting force can be measured at X and Y direction. The

magnitudes of cutting force are dependent on the cutting speed, feed rate, and the

2

Matetial hardness is another factor to be considered in cutting process. Thi

factor contributes to surface roughness and tool life. \llaterial hardness for mild steel I 018 CF and mild steel DF2, are usually between 42- 45 HRC. It is expected that tool wear and cutting forces will increase if the material is too high.

Effects of cutting tool wear and material hardness on cutting forces are major problem in metal cutting process. In this project high speed steel (HSS) cutting tool blank, mild steel 1018 CF and mild steel DF2 is used for experimental. Meanwhile

cutting force was measured using 2-axis mechanical dynamometer. The parameters of this experiment are feed rate, depth of cut and cutting speed. The plotted graph

were shown the polar of result for variable parameters.

1.2 Research Objective.

The main objective on this project i

s:-The main objectives are:

1. To measure cutting forces for different tool geometry at constant feed rate.

11. To measure cutting forces for similar tool geometry at vary1ng feed rate.

111. To measure cutting force at constant kinematics parameters for different

material hardness.

1.3 Structure of the Project.

Chapter I of the project describe briefly about the introduction of them. It

follows with chapter 2, that include literature review one metal cutting process. The explanation in tool wear, material hardness, and cutting force are also included.

3

the explanation about cutting parameters that usc directly cutting operation. E\'cn.

procedure and technique using external equipment also explained.

Result and discussion are described in chapter 4. The plotted graph between

each cutting parameters are showed. However, discussion for every graph and also

comparisons are made. lllustration also include to explanation. Chapter 5, conclude

the project compulsory the result of effect tool wear and material hardness on cutting forces. As a result, recommendation for the future improvement are identified and

4

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

In turning material is removed from workpiece while the workpiece rotating.

There are several parameters, which have, significant impact into cutting process. However, tool wear and material hardness have a relationship between these

parameters. These two parameters will influence the amount of generated cutting forces. A brief description of cutting force and review of specific of tool wear will

describe.

Cutting force (Fe), act between the cutting tool and cutting speed. The force generated, when the spindle rotate and the cutting tool touch the workpiece. There are three cutting force acting on the cutting tool, which are Tangential force (Fe),

Feed force (Ft) and Radial force (Fr). Forces will be measured by using the dynamometer.

The tangential force or cutting force (Fe) is generated due to the rotating workpiece and the resistance to rotation between cutting tool and workpiece. The direction of the cutting forces is perpendicular to the cutting tool. In a normal operation, a tangential force is the highest of the three forces and account for 98% of the power required by the operation George Schneider (200 1 ).

5

negative and the tool is pulled into the workpiece. Thrust forces in metal cutting are

importance because of the tool holder. work holding, and machine tool. The tool

need to sufficiently stiff to the workpiece. to make sure the thrust force not too high

and can be effect to other parameters.

There are several problems to overcome during the cutting process. One of

the problems was tool wear, where the tool will be significant influence to

workpiece. The rate of tool wear depends on tool and workpiece material, tool shape,

cutting fluids, process parameters. and machine-tool characteristics. There are two

basic type of wear, these two regions is flank wear and crater wear. A brief description of tool wear is described.

Tugrul Ozel et al. (2003) studied the effect of cutting edge geometry,

workpiece hardness, feed rate, and cutting speed on surface roughness and forces in

finish turning of hardened AISI H 13 steel. They observed the effect of workpiece

hardness, cutting edge geometry, feed rate, and cutting speed on surface roughness

are statistically significant. Therefore, the lower workpiece surface hardness and

honed edge geometry resulted in lower tangential and radial forces.

However. cutting parameters are important to the metal cutting. M.Liang et

al. (2001) investigated the integration of cutting parameter selection and tool

adjustment decision for multipass turning. They are measured with various

parameters simultaneously in turning operations. From the experiments they are

conclude that the effect of machining parameters and tool adjustment are significant

6

2.2 Material Removal.

The material removal rate (MRR) is the volume material removes from the

workpiece per unit time (mm3/min). For each revolution of workpiece, cutting tool

remove a layer of material. Process removal referring to the rotation of spindle;

where tool travel in one revolution feed and the depth of cut. The major parameters of interest for the material removal process can be classified for two. Binu Paul John (2003), the parameters that describe the material and parameters that describe the cutting process.

MRR=bxtxv (2.1)

From the equation above, material removal can be calculated to determine the volume material removes. Chip thicknesses represent forb, t is feed, and v is cutting speed.

2.3 Cutting Forces.

Forces turning can provide three forces acting on cutting tool. These forces are important in design of machine tools, as well as in the deflection of tools and workpiece for precision machining operations. However, the relationship of the

cutting variables to the cutting forces such as tool angle, feed rate, and cutting speed.

These are significantly influence to the tool and workpiece. Nevertheless, using the merchant's circle theory, forces also can be calculated. A brief description on the

merchant's circle also included.

While the tool is forced to cut the workpiece, a chip produced from the

shearing zone and moves on along the rake face of the tool until it curves off or brakes up. Cutting force and normal force acting together to perform the cutting operation. The parameters of forces and geometry with the primary deformation zone

are shear force (F), nonnal force (F ) and the shear angle. TI1e secondary parameters

7

deformation zone is friction force (F). normal force (N) and the rake angle (a). The

cutting force (F ) and thrust force (F) that can be measurable with the cutting process

C I

using the Merchant"s anal)tical model for t'"·o-dimensional orthogonal cutting

mechanics. Figure 2.1 shows Merchant's force circle of the forces involved in

orthogonal cutting.

a

/ i \

,.---- - -- ---<...' - ·

~

/_.-

--

~

i

I I

'

\

\

\

I

. F

~~

---,/

)

-·

/ }

'

'\

I

I F !

v

i

\

/

\

\

Figure 2.1: Merchant's composite force circle in orthogonal cutting [Binu Paul

John (2003)]

Figure 2.1 above, shown the shear plane AB is inclined to the cutting

direction with an angle <D (shear angle). The resultant force, R. is resolved into the

shear force F5 along the shear plane and normal force Fs perpendicular to the shear

plane. At the rake face, the resultant force R is resolved into friction force F along

the rake face and normal force N normal to the rake face. R is again resolved into

cutting force F along the cutting direction and thrust force F normal to the cutting

c I

direction. F and F can be measured using a dynamometer and can be used to

C I

calculate the other force parameters using the equations given below:

F =Fe sin a+ Ft cos a (2.2)

Fs =Fe cos¢

-

¢

Fn =Fe sin¢+ Ft co

s¢

2.4 Single Point Cutting Tool.

In metal cutting have a several factors are influencing on cutting process, one

of the factors is cutting tool (tool angles and tool wear). Therefore, the shape and

position of the tool are relative to the workpiece. Another fact is location of the

cutting edge and the direction of cut.

The shape and position of the tool with relative to the workpiece have been

effect to the metal cutting. The geometries of shape are nose, hone and sharp edge.

Rake angle on cutting tool is importance to controlling both the direction of chjp

flow and strength of tool. Tool wear will be effect to the tool life, the quality of the

machined surface, and consequently, the economics of cutting operations. Figure 2, shows the cutting tool terminology used in right hand cutting operation.

£NO

CU ,UAHC(

AJ~~car

(C45) is a model of this tool and size of tools; 8mm x 1 Omm x l60mm long. Table

2.1 shows the general recommendations for turning angles.

Table 2.1: General Recommendations HSS Cutting Tool Angles [Manufacturing

Engineering and Technology]

Material Back rake Side rake End relief Side relief

Aluminum 20 15 12 10

Cooper alloys 5 10 8 8

Steel 10 12 5 5

Stainless steels 5 8-10 5 5

2.4.1 Rake Angle.

9

The slope of the face on cutting tool is determined by the back- rake and side

rake angles. The side- rake angles is measured perpendicular to the side-cutting edge

and the back-rake angles is measured parallel to the side cutting edge. Positive rake

angle are generally preferred because less cutting force is required in order to take a

given size cut as compared to a tool with negative side-rake angles.

There are two rake angles back rake and side-rake. For the turning and boring

process, the side rakes the most influential. These cause by which two major effects

during the metal cutting process. The effects are influence on tool strength and