comparative assessment of standard and wiper …...comparative assessment of standard and wiper...

Comparative assessment of standard and wiper insert on surface roughness

in turning of Titanium alloy (Ti-6Al-4V)

Pravin A. Mane1, Nilesh T. Mohite

2, Vinay S.Kale

3

1, 2, 3 Assistant professor, Mechanical Engg. Department, D.Y.Patil college of engg., & Technology, Kolhapur.

Maharashtra, India,

Ashwin A. Desai4

4 Assistant professor, Mechanical Engg. Department, Dr.D Y Patil Technical Campus,Talsande,.

Maharashtra, India,

Abstract Titanium alloys are widely used in the engineering field,

namely in the aerospace, automotive and biomedical parts,

because of their high specific strength and exceptional

corrosion resistance. However, the machinability of titanium

alloys is difficult due to their low thermal conductivity and

elastic modulus, high hardness at elevated temperature, and

high chemical reactivity. This article reviews the state of the art of machinability of titanium alloys, and focuses on the

analysis of the process details, namely the especial

techniques for cutting improvement, machining forces, chip

formation and cutting temperature. The influence of

titanium properties on the machinability is also highlighted.

Particular attention is given to the turning process of Ti-6Al-

4V alloy.

Keywords: cutting improvement, Machineability,

Titanium alloys,

Introduction Machining

Machining is a process in which material is

removed gradually from a work piece including metal

cutting with single point and multipoint tools and grinding

with abrasive wheels. It is the process in which a tool

removes material from the surface of metal block, through

relative movement and application of force. This process is most important since almost all the products get their final

shape and size by metal removal, either directly or

indirectly. The machining processes are commonly used by

manufacturing industries in order to produce high quality

and very complex products in a short time. These machining

processes include large number of input parameters which

may affect the cost and quality of the products. Selection of

optimum machining parameters in such machining

processes is very important to satisfy all the conflicting

objectives of the process. [1,2].

Figure1: Schematic Representation of Machining

Concept of Wiper Inserts

Figure2: Concept of conventional and wiper inserts

The wiper technology for turning is based on a carefully

developed series of radii that make up the cutting edge. On a

conventional insert, the nose of the edge is just one radius.

International Journal of Engineering Research and Technology. ISSN 0974-3154 Volume 10, Number 1 (2017) © International Research Publication House http://www.irphouse.com

734

The wiper edge, however, is made up of a large,

main radius complemented by several smaller radii. The

long wiper edge should not misshape the surface nor

generate unacceptable cutting forces. The wiper insert

should also be as straightforward to set up and use as an

ordinary insert. [7]. In turning with a single-point tool, the surface

finish is determined by the feed rate and nose radius, as

these are in a direct relationship to the profile height of the

surface (Rmax). This means that the higher the feed, the

rougher the surface generated by the edge of a given nose

radius. Wiper inserts have changed this through the effect of

their specially developed edges that smooth the scalloped

tops that would otherwise have been created. An additional

important feature is their improved chip-breaking capability.

Wiper geometries are also designed to combine good chip

control at low feeds and smooth chip breaking at high,

productive feeds.[5,6].

Wiper insert in turning

In turning, the development of new wiper insert is a strategy

for productivity improvement. Manufacturers claim to

improve surface finish two times over standard inserts.

Alternatively, the feed rate can be increased at least by 20%

without sacrificing surface finish requirement. A finish

turning operation or sometimes usual grinding may not be

required. A wiper insert’s nose is slightly flattened. The

geometry becomes a combination or a blend of radii.[3]. The

edge of the insert essentially traces a path around the edge of two overlapping circles, leaving the tip with a slightly

elliptical shape. The blended radii knock off the high points

created by the feed lines and provide a smoother finish

without increasing the nose radius or reducing the feed.

Wiper inserts are basically high feed tools for using with

light depth of cut. The manufacturers claim the wiper inserts

last longer than conventional inserts, even though they were

not designed for it. [4].

Experimental Setup Workpiece Material:

For our experiment Titanium Alloy is used as

workpiece material.

Table No. 1: Chemical composition of Titanium alloy

Insert Specification:

Figure3: Insert

Table No. 2: Insert Nomenclature

C N M G 12 04 08 MT

1 2 3 4 5 6 7 9

Insert Specification: CNMG 12 04 08 MT

CNMG 12 04 08 WT

Experimental Details We have done this work which aims to evaluate

effect of wiper insert in turning on Titanium alloy. The

major emphasis of this project is to study performance of

wiper insert in turning of Titanium Alloy which has

hardness more than 40 HRC, the performance is evaluated in terms of tool wear, surface finish and quality of chips

which are major parameters to describe the surface integrity.

Number of experiments is conducted at different values of

feed rates, speed and depth of cut by suitable grade of

carbide. The cutting tool and workpiece surface are

examined by appropriate measuring instrument like Surface

Roughness Tester, Toolmaker‟s microscope keeping in view

surface integrity, to decide how wiper inserts affects cutting

forces, surface finish, and tool wear of Titanium Alloy. The

results of machining with conventional inserts and wiper

inserts will be compared to study surface integrity.

According to the insert selection and for hard turning, the cutting parameters that are speed, feed and

depth of cut are-

Table No.3: Process parameters

Parameters

Levels

I II III

Speed (N) (rpm) 530 740 950

Feed (f) (mm/rev) 0.10 0.15 0.20

Depth of cut (d) (mm) 0.5 1 1.5

Types of inserts C W

Design of Experiment: The design of experiment technique is tool, which

permits us to carry out the modeling and analysis of the

influence of process variables on the response variables. The response variable is an unknown function of the process

variables, which are known as design factors. In turning

operation, there are a large number of factor that can be

considered as machining parameters. The depth of cut

(DOC, mm), spindle speed (N, rpm) and feed rate (f,

mm/rev) of cutting tool is the most widespread machining

parameters taken by the researchers.

Design of Experiments (DOE) techniques enables

designers to determine simultaneously the individual and

interactive effects of many factors that could affect the

output results in any design. DOE also provides a full

insight of interaction between design elements; therefore, it helps turn any standard design into a robust one. Simply put,

DOE helps to pin point the sensitive parts and sensitive

areas in designs that cause problems in Yield. Designers are

then able to fix these problems and produce robust and

higher yield designs prior going into production. DOE is

Ti Al V Fe O

90% 6% 4% Max

0.25%

Max 0.2%


735

also very useful in getting information on the interactions

between the elements in a design and how these interactions

affect the variation in the output measure.

Minitab 16 software is used for design of

experiment. Minitab is Statistical Analysis software that

allows ease to conduct analyses of data. It is a statistical software package that was designed especially for the

teaching of introductory statistics courses. It is our view that

an easy-to-use statistical software package is a vital and

significant component. Minitab is an interactive program.

By this we mean that you supply Minitab with input data, or

tell it where you„re input data is, and then Minitab responds

instantaneously to any commands you give telling it to do

something with that data. Minitab has two main types of

files, projects and worksheets. Worksheets are files that are

made up of data; Projects are made up of the commands,

graphs and worksheets.

Designed experiments are often carried out in four phases: planning, screening (also called process

characterization), optimization, and verification. For

example creating, analyzing, and plotting experimental

designs. [8].

Design of Experiment (DOE)

Table No.4: Process Parameter

Parameters

Levels

I II III

Speed (N) (rpm) 530 740 950

Feed (f) (mm/rev) 0.10 0.15 0.20

Depth of cut(d)

(mm) 0.5 1 1.5

Types of inserts C W

The data from above table is put into the

orthogonal array which is formed by using Taguchi Design

and these tables containing actual values of input parameters

are used while performing Experiment.

In our project there are three input parameters, all

three parameters are having 3 levels. So from the available

designs in Minitab (Taguchi) we have chosen L9 array. The

design is as follows: Table No.5: Orthogonal Array of Taguchi L9

Sr. No. Speed

(rpm)

Feed(mm/rev) DOC(mm)

1 530 0.1 0.5

2 530 0.15 1

3 530 0.2 1.5

4 740 0.1 1

5 740 0.15 1.5

6 740 0.2 0.5

7 950 0.1 1.5

8 950 0.15 0.5

9 950 0.2 1

Experimentation:

1. Prepared raw material having dimensions Ø30×70 mm is

turned on CNC turning center. And the parameters obtained

from the design of experiment are used for experiment.

2. From 70 mm length of workpiece 15 mm length is used for holding it into chuck. And 25 mm length is used for

turning.

3. For each workpiece fresh corner of insert is used for

analyzing the effect of changed parameters.

Experimental Results

Roughness Pattern Obtained By Roughness Tester:

By Conventional inserts

N=530 rpm, feed=0.1 mm, DOC=0.5 mm N=740 rpm,

feed=0.2 mm, DOC=0.5 mm

N=950 rpm, feed=0.1 mm, DOC=1.5 mm N=950 rpm,

feed=0.2 mm, DOC=1 mm

Figure4: Roughness pattern by conventional inserts


736

By Wiper inserts:

N=530 rpm, feed=0.15 mm, DOC=1 mmN=740 rpm,

feed=0.2 mm, DOC=0.5 mm

N=740 rpm, feed=0.15 mm, DOC=1.5 mmN=740 rpm,

feed=0.2 mm, DOC=0.5 m

Figure5: Roughness pattern by wiper inserts

Roughness Values Table No.6: Roughness values obtained by conventional

inserts

Exp

t.

No.

Spee

d

(rp

m)

Feed

(mm/re

v)

DO

C

(m

m)

Ra Avg

. Ra Tri

al 1

Tri

al 2

Tri

al 3

1.

530

0.1

0.5

0.43

2

0.44

8

0.43

1

0.43

7

2. 530 0.15

1

0.387

0.358

0.380

0.375

3. 530

0.2

1.5 0.80

6

0.83

9

0.83

3

0.82

6

4.

740

0.10

1

0.27

1

0.32

4

0.32

9

0.30

8

5. 740

0.15 1.5

0.355

0.373

0.361

0.363

6.

740

0.20

0.5

0.55

9

0.57

9

0.59

0

0.57

6

7.

950

0.10

1.5

0.29

5

0.32

5

0.33

4

0.31

8

8.

950

0.15

0.5

0.31

5

0.28

0

0.29

3

0.29

6

9. 950 0.20 1 0.38

1

0.34

8

0.39

9

0.37

6

Table No.7: Roughness values obtained by wiper inserts

Exp

t.

No.

Spee

d

(rp

m)

Feed

(mm/re

v)

DO

C

(m

m)

Ra Avg

. Ra

Tri

al 1

Tri

al 2

Tri

al 3

1.

530

0.1

0.5

0.39

5

0.40

7

0.41

3

0.40

5

2. 530

0.15

1

0.69

9

0.69

9

0.70

3

0.70

1

3. 530

0.2

1.5

1.31

0

1.32

3

1.33

0

1.32

1

4.

740

0.10

1

0.35

8

0.37

0

0.36

1

0.36

3

5.

740

0.15

1.5

0.72

8

0.76

5

0.76

0

0.75

1

6. 740

0.20 0.5

1.29

9

1.23

7

1.286

1.274

7. 950

0.10 1.5

0.53

3

0.39

5

0.407

0.524

8.

950

0.15

0.5

0.413

0.699

0.70

1

0.701

9. 950 0.20 1

0.70

3

1.31

0

1.32

3

1.32

1

Analysis of Experimental Results

Anova for Surface Roughness Data The ANOVA and AOM results for surface roughness (Ra)

data (Table) for conventional insert showed that the selected full factorial model was significant. Feed (P value=0.001)

was the most significant parameter having maximum

contribution. Speed and Depth of cut was other parameter

which affected the surface roughness significantly but


737

contributed less than the feed. Speed and DOC are 2nd& 3rd

significant parameters respectively.

Table No.8: Analysis of Variance for Ra, using Adjusted SS

for Tests

Sour

ce

D

F

Seq

SS

Adj

SS

Adj

MS F P

spee

d

2 0.022

23

0.022

23

0.011

12

23.33 0.0

41

feed 2 1.170

74

1.170

74

0.585

37

1228.

62

0.0

01

doc 2 0.007

71

0.007

71

0.003

86

8.09 0.1

10

Error 2 0.000

95

0.000

95

0.000

48

Total 8 1.201

64

S = 0.0218276 R-Sq = 99.92% R-Sq (adj) = 99.68%

Regression Equation

Ra = -0.666143 + 0.000234127 speed + 8.76667 feed +

0.0153333 doc

Figure6: Mean effect plot showing effect of various process

parameters on surface roughness for conventional insert

From fig no.6, it is observed that Surface roughness is minimum at speed 740 rpm and increases up to 950 rpm

feed 0.10 mm/rev and increases to 0.20 mm/rev and DOC 1

mm and increases up to 1.5 mm.

The ANOVA and AOM results from table no.9 for wiper

insert showed that the selected full factorial model was

significant. Feed (P value=0.085) was the most significant

parameter having maximum contribution. Speed and Depth

of cut was other parameter which affected the surface

roughness significantly but contributed less than the feed.

Speed and DOC are 2nd& 3rd significant parameters

respectively.

Table No.9: Analysis of Variance for Ra, using Adjusted SS

for Tests

Source DF Seq SS Adj SS Adj MS F P

speed 2 0.070982 0.070982 0.035491 6.45 0.134

feed 2 0.118400 0.118400 0.059200 10.75 0.085

doc 2 0.033601 0.033601 0.016800 3.05 0.247

Error 2 0.011010 0.011010 0.005505

Total 8 0.233992

S = 0.0741942 R-Sq = 95.29% R-Sq(adj) = 81.18%

Regression Equation

Ra = 0.387627 - 0.000514286 speed + 2.38333 feed + 0.066 doc

Figure7: an effect plot showing effect of various process

parameters on surface roughness for wiper insert

From fig no.7, it is observed that Surface roughness is

minimum at speed 950 rpm, feed 0.10 mm/rev and increases

to 0.20 mm/rev and DOC 1 mm and increases up to 1.5 mm.

From the ANOVA of surface roughness it is

observed that only feed rate affects the surface roughness

significantly. An increase in the feed rate increases the

surface roughness, which is known from the fundamentals of metal cutting

Where f is feed rate (mm/rev) and r is tool nose

radius in mm. From above graph it is observed that the

roughness value gradually increases within the feed range

0.10-0.20 and there is drastic increase in roughness value after 0.15 to 0.2. Along with feed rate speed and DOC are

statistically significant. Ra value is directly proportional to

DOC up to 0.3 mm. Thereafter there is gradual increase in

Ra values as observed in above graph. From above graph it

is observed that wiper insert gives minimum roughness

value than conventional Insert. The geometry of the cutting

edge has influence on the machined surface roughness as

wiper insert has multi radii. The cutting speed N=950 rpm is

higher level which gives minimum roughness value as

compared to lower and medium levels of cutting speed.

Statistically as observed speed is having least influence on

surface roughness.


738

Anova for Tool Wear Data

The ANOVA and AOM results for Tool Wear data (Table)

for conventional insert showed that the selected full factorial

model was significant. Feed (P value=0.720) was the most

significant parameter having maximum contribution. Speed and Depth of cut was other parameter which affected the

surface roughness significantly but contributed less than the

feed. DOC and Speed are 2nd& 3rd significant parameters

respectively.

Table No.10: Analysis of Variance for tool wear, using

Adjusted SS for Tests

Sourc

e

D

F

Seq SS Adj SS Adj MS F P

speed 2 0.00151

7

0.00151

7

0.00075

8

0.2

7

0.78

4

Feed 2 0.00215

0

0.00215

0

0.00107

5

0.3

9

0.72

0

Doc 2 0.00186

7

0.00186

7

0.00093

3

0.3

4

0.74

7

Error 2 0.00551

7

0.00551

7

0.00275

8

Total 8 0.01105

0

S = 0.0525198 R-Sq = 50.08% R-Sq(adj) = 0.00%

Fig No.17: M Figure8: mean effect plot showing effect of various process

parameters on tool wear for conventional insert

Regression Equation

Tool wear = 0.0523413 + 3.1746e-005 speed – 0.35 feed +

0.0333333 doc

From fig no.8, it is observed that Surface roughness is minimum at speed 740 rpm and increases up to 950 rpm,

feed 0.20 mm/rev and DOC 0.5 mm and increases up to

1.5 mm.

The ANOVA and AOM results from table no.11

wiper insert showed that the selected full factorial model

was significant. Speed (P value=0.406) was the most

significant parameter having maximum contribution. Depth

of cut and feed rates other parameter which affected the

surface roughness significantly but contributed less than the

feed. DOC and feed are 2nd& 3rd significant parameters

respectively.

Table No.11: Analysis of Variance for tool wear, using

Adjusted SS for Tests

Source DF Seq SS Adj SS Adj MS F P

speed 2 0.0007389 0.0007389 0.0003694 1.46 0.406

feed 2 0.0006889 0.0006889 0.0003444 1.36 0.423

doc 2 0.0007056 0.0007056 0.0003528 1.40 0.417

Error 2 0.0005056 0.0005056 0.0002528

Total 8 0.0026389

S = 0.0158990 R-Sq = 80.84% R-Sq(adj) = 23.37%

Regression Equation

Tool wear = 0.027619 - 5.15873e-005 speed + 0.2 feed +

0.0216667 doc

Figure9: Mean effect plot showing effect of various process

parameters on tool wear for wiper insert

From fig no.9, it is observed that Surface roughness is

minimum at speed 950 rpm, feed 0.10 mm/rev and increases

to 0.20 mm/rev and DOC 0.5 mm and increases up to 1.5 mm.

Tool Wear Measurement In this work, measurement of the wear on the flank surface

carried out by using Tool maker’s microscope.

Table No.12: Measured values of tool Wear

Sr.

No.

Type

of

insert

Speed

(rpm)

Feed

(mm/rev)

DOC

(mm)

Tool

wear(mm)

1 C 530 0.1 0.5 0.04

2 C 530 0.15 1 0.095

3 C 530 0.2 1.5 0.04

4 C 740 0.1 1 0.03

5 C 740 0.15 1.5 0.05

6 C 740 0.2 0.5 0.04

7 C 950 0.1 1.5 0.14


739

8 C 950 0.15 0.5 0.05

9 C 950 0.2 1 0.025

10 W 530 0.1 0.5 0.03

11 W 530 0.15 1 0.06

12 W 530 0.2 1.5 0.07

13 W 740 0.1 1 0.025

14 W 740 0.15 1.5 0.04

15 W 740 0.2 0.5 0.05

16 W 950 0.1 1.5 0.045

17 W 950 0.15 0.5 0.01

18 W 950 0.2 1 0.04

S/N Ratios Plots

For Surface roughness

Figure10: S/N ratio plot showing effect of various process

parameter on Ra for conventional inserts

Fig No. Figure11: S/N ratio plot showing effect of various process

parameters on Ra for wiper inserts

For Tool wear

Figure12: S/N ratio plot showing effect of various process

parameters on tool wear for conventional inserts

Figure13: S/N ratio plot showing effect of various process parameters on tool wear for wiper inserts

3d Surface Plots

From ANOVA analysis we have observed that feed is the

most significant process parameter for surface roughness

value Ra. Therefore the graph shows that with increase in

feed the surface roughness value also get increases in

proportion. And speed is second significant process

parameter which shows gradual increase in roughness value

from lower to higher values.

• For conventional inserts

Figure14: Surface plot showing effect of speed & feed on

Ra

9 5 0 7 4 0 5 3 0

3 2 . 5 3 0 . 0 2 7 . 5 2 5 . 0

0 . 2 0 0 . 1 5 0 . 1 0

1 . 5 1 . 0 0 . 5

3 2 . 5 3 0 . 0 2 7 . 5 2 5 . 0

s p e e d

M e a n o f S N r a t i o s

f e e d

d o c

M a i n E f f e c t s P l o t f o r S N r a t i o s f o r T o o l W e a r D a t a M e a n s

S i g n a l - t o - n o i s e : S m a l l e r i s b e t t e r

9 5 0 7 4 0 5 3 0

3 0 . 0 2 8 . 5 2 7 . 0 2 5 . 5 2 4 . 0

0 . 2 0 0 . 1 5 0 . 1 0

1 . 5 1 . 0 0 . 5

3 0 . 0 2 8 . 5 2 7 . 0 2 5 . 5 2 4 . 0

s p e e d


f e e d

d o c

M a i n E f f e c t s P l o t f o r S N r a t i o s f o r T o o l W e a r D a t a M e a n s

S i g n a l - t o - n o i s e : S m a l l e r i s b e t t e r

9 5 0 7 4 0 5 3 0

8

4 0

0 . 2 0 0 . 1 5 0 . 1 0

1 . 5 1 . 0 0 . 5

8

4 0

s p e e d


f e e d

d o c

M a i n E f f e c t s P l o t f o r S N r a t i o s f o r S u r f a c e R o u g h n e s s D a t a

M e a n s

S i g n a l - t o - n o i s e : S m a l l e r

i s b e t t e r


740

This surface plot shows that at the lower feed values the

surface roughness values are less and with increase in feed

there is increase in surface roughness values.

Figure15: Surface plot showing effect of speed & doc on Ra

This surface plot shows that at the lower speed and DOC

values the surface roughness values are less.

Figure16: Surface plot showing effect of feed& doc on Ra

This surface plot shows that at the lower feed and higher

DOC values the surface roughness values are less.

• For wiper insert


Ra

This surface plot shows that at the maximum speed and

lower feed values the surface roughness values are less.

Figure18: Surface plot showing effect of speed & doc on Ra

This surface plot shows that at the higher speed and lower

DOC values the surface roughness values are less.


Ra

This surface plot shows that at the medium feed and DOC

values the surface roughness values are less.

Conclusion

In this study, performance of wiper insert in Hard

turning of Titanium alloy has been evaluated in terms of

surface roughness and Tool Wear.

Conclusion is as follows:

• When multiple parameters are considered, it has been

observed that feed is most influencing parameter.

• In this experiment it has been observed that in comparison with wiper insert and conventional insert Ra value achieved

by wiper insert (Ra=0.308 µ) is less.

• Hard turning with wiper insert can be used as alternative for

grinding process.

• For single output parameter i.e. for single objective like

Surface Roughness, Tool Wear, The techniques like

ANOVA and AOM gives results as

• For surface roughness (Ra), Feed (P value=0.085) is the

most significant parameter having maximum contribution.


741

• For Tool Wear, speed (P value=0.406) is the most

significant parameter having maximum contribution.

References

[1] Jagadale Amitkumar Hanamantrao, Jadhav B. R.,

“Comparative Assessment of Wiper and Standard Insert On

Surface Roughness In Hard Turning Of En-9 Steel”,

Proceedings Of 10th Irf International Conference, 116-119,

2014.

[2] J. Guddata. b, R. M‟Saoubia, P. Alma, D. Meyerb, “Hard turning of AISI 52100 using PCBN wiper geometry inserts

and the resulting surface integrity”, Procedia Engineering 19

118–124, 2011.

[3] K.Venkatesan, R.Ramanujam, Vimal Saxena, Rachit

Pandey, “Performance Evaluation of Ordinary and Wiper

Inserts in Dry Turning of Inconel 718 Super Alloy using

Grey-Fuzzy Algorithm – A Hybrid Approach”, 5th

International & 26th All India Manufacturing Technology, Design and Research Conference 449-1 to 449-6, 2014.

[4] Tugrul Ozel ,”Neural network process modelling for turning

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258, 2009.

[5] M. Dogra,V. S. Sharmab, J. Durejac, “Effect of tool

geometry variation on finish turning”, Journal of Engineering Science and Technology Review 1-13, 2011.

[6] Nikunj Patel, Prof. R. K. Patel, Prof. U. J. Patel, “Insert

Selection for Turning Operation on CNC Turning Centre

using MADM Methods”, International Journal of Latest

Trends in Engineering and Technology,49-59, 2012.

[7] Jaroslava Fulemova , Zdeněk Janda, “Influence of the Cutting Edge Radius and the Cutting Edge Preparation on

Tool Life and Cutting Forces at Inserts with Wiper

Geometry”, Procedia Engineering 69 ,565 – 573, 2014.

[8] J. Nithyanandam, Sushil LalDas, K. Palanikumar,“Surface

roughness analysis in turning of titanium alloy by

nanocoated carbide insert”, Procedia Materials Science 5

,2159 – 2168, 2014.

[9] V Krishnaraja, S Samsudeensadhama, R Sindhumathia, P Kuppanb, “A study on high speed end milling of titanium

alloy”, Procedia Engineering 97 ,251– 257, 2014


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