A study comprising of different surface roughness parameters of AZ31B Mg alloy was done in this experiment successfully. The study was done by turning AZ31B Mg alloy under varied feed, depth and cooling condition i.e., dry, conventional flood, MQL. Different amount of surface roughness was measured by the service of a roughness tester. The collected data from the turning operation were used to analyze and get desirable results on behalf of low surface roughness. The analysis was done by means of Taguchi method and the following results were shown:  The experimentation shows that, the cutting speed has insignificant impact on the studied surface roughness parameters.  Feed rate has significant influence over the surface roughness parameters. It expressed itself as the most dominant control factor to determine a better surface roughness parameter.  Depth of cut has insignificant influence over the surface roughness parameter and it has less effect on the roughness parameters compared to feed rate.  In cutting condition, MQL emerged as the major cooling condition compared to other two conditions which are dry and flood condition. The future study can be conducted on the investigation of tool wear and chip morphology in turning of Mg AZ31B alloy under dry, flood and MQL conditions.

1. IMRAN SARKER
INDUSTRIAL & PRODUCTION ENGINEER
AHSANULLAH UNIVERSITY OF SCIENCE & TECHNOLOGY
ID: 14-01-07-065
Parametric study of surface roughness in turning of
AZ31B Mg alloy under different cooling conditions
SUPERVISOR: MOZAMMEL MIA
ASSISTANT PROFESSOR, MPE, AUST

2. 2
Contents
 Introduction
 Literature review
 Scope of work
 Objective
Contents
 Methodology
 Experimental conditions
 Results and discussion
Contents
 Results and discussion
(cont.)
 Conclusion

3. Framework
 Introduction
 Literature review
 Scope of work
 Objectives
 Methodology
 Results and discussion
 Conclusion
3

4. Introduction
 AZ31B Mg alloy is used in aerospace and automobile industry
 This is due to its light weight but good specific strength property
 However, the processing of Mg alloy is mostly done by using machining
 Turning stands out as one of the mostly used machining processes
 The quality of produced products by turning can be evaluated by the roughness
value
 Surface roughness value is determined by different roughness parameters
 Considering the above facts, the parametric study of surface roughness in turning of
Mg AZ31B alloy is performed
4

5. Literature review
Author(s) Year Remarks
Pu et al. 2012
• Surface roughness was studied for AZ31B under cryogenic
cooling
• Improved roughness was found by cryogenic condition
Villeta et al. 2011
• Dry turning of Mg alloy was done
• Led to high surface roughness value between 0.975 and 1.425
µm
Bhowmick et al. 2010
• Dry and MQL were used in drilling of Mg alloy
• Dry cutting was found as the most appropriate condition to
avoid tool failure
5

6. Literature review
Author(s) Year Remarks
Dinesh et al. 2010
• Used cryogenic liquid while turning ZK60 Mg alloy
• Cryogenic liquid during machining improves the surface
characteristics
Fang et al. 2005
• The mean temperature on the flank face was presented.
• Predicted the occurrence of fire in high speed cutting of
magnesium alloys.
Tönshoff et al. 1997
• Turning operation of AZ91 HP was done
• The influence of the cooling conditions gives different
cutting tool and material and coating results
6

7. Scope of work
 Based on the knowledge found in the literature reviews, there is scope of conducting
experimental study in turning operation of AZ31B Mg alloy regarding-
Surface roughness parameters:
 Arithmetic mean of roughness parameter (Ra)
 Root mean square roughness (Rq)
 Average maximum height surface roughness (Rz)
 Maximum height of the profile (Rt)
 Maximum profile peak height (Rp)
 Maximum profile valley depth (Rv)
7

8. Illustration of surface roughness parameters
8
Graphical
view of Ra
,Rq, Rt
Graphical
view of Rp,
Rv, Rz

9. Objectives
 Study of different surface roughness parameters in turning of AZ31B Mg
 Determine the influence of dry, flood and MQL on roughness parameters
 Evaluate the influence of cutting speed, feed rate and depth of cut on the surface
roughness parameters
9

10. Methodology
10
Start
Straight
Turning
DOE by
Taguchi
Finding scope
and defining
objective
Literature
review
Input: Vc, f, d
Output: Ra, Rq, Rz, Rp,
Rt, Rv
Environment: Dry, wet,
MQL
Measurement of
surface roughness
parameters: Ra, Rq, Rz,
Rp, Rt, Rv
Successful
parametric
study
End

11. Experimental conditions
Material: AZ31B Mg Alloy
Treatment: High pressure die casting by analysis from International Magnesium
Association (IMA).
Dimension: Length = 500 mm; Diameter = 70 mm.
Cutting tool: Coated tungsten carbide (WC).
Dimension: Length = 12 mm; Width = 12 mm; Height = 5 mm.
Coolant: Conventional flood cooling and MQL.
Machine : Lathe [Power: 7.5 HP, Maximum spindle speed: 1600 rpm, Manufacturing
country: China].
11

12. Experimental conditions (contd.)
Control factors in cutting parameters
 Cutting speed: 45 m/min,105 m/min,165 m/min
 Feed rate: 0.10 mm/rev, 0.14 mm/rev, 0.18 mm/rev
 Depth of cut: 0.5 mm, 1 mm, 1.5 mm
 Cutting conditions: Dry, wet, minimum quantity lubrication
12

13. Photographic views of experimental equipments
AZ31B Mg
alloy as work
material
Turning
operation
*Experimental runs were conducted in Machine shop laboratory of MPE dept, AUST 13
Surface
roughness
tester
Tool holder &
insert

14. Results and discussion
The adopted analysis process is performed using the followings-
 Main effect plots
 Contour plots
 3D surface plot
 Response table
14

15. Arithmetic mean of roughness parameter (Ra)
 Ra is most significantly affected by the
changes in the feed rate
 Feed rate is the most dominant factor
among all four factors
15
Table 4.1.1
Response Table for mean of means of average surface
roughness (Ra). [Smaller is better]
Level Cutting speed Feed rate Depth of cut
Cutting
condition
1 1.0679 0.6410 1.0605 1.1867
2 1.1194 1.1119 1.1019 1.0799
3 1.1125 1.5469 1.1375 1.0332
Delta 0.0515 0.9059 0.0770 0.1536
Rank 4 1 3 2

16. Arithmetic mean of roughness parameter (Ra) (Cont.)
 The depth of cut hardly changes the average
surface roughness value; but the feed rate
has significant effect
 When the feed rate is increasing the value of
Ra is increasing in a more drastic manner
16
5.0
0.1
.0 5
1.0
51.
0 521.
0.100
5.1
0
00.15
0 521.
0.175
51.
0.2
aR
deeF
tuCfohtpeD
urfS ce Plot of Ra vs Feed, Cutting Speeda
Depth of Cut
Feed
1.501.251.000.750.50
0.175
0.150
0.125
0.100
>
–
–
–
–
–
< 0.50
0.50 0.75
0.75 1.00
1.00 1.25
1.25 1.50
1.50 1.75
1.75
Ra
Contour Plot of Ra vs Feed, Depth of Cut

17. Root mean square surface roughness parameter(Rq)
 The mean of Rq is less significantly affected
by the changes in the cutting speed
 Cutting condition is the second dominant
factor after feed rate
Table 4.2.1
Response Table for mean of means of root mean square
roughness (Rq) [Smaller is better]
Level Cutting speed Feed rate Depth of cut
Cutting
condition
1 1.2626 0.7876 1.2551 1.4190
2 1.3328 1.3080 1.3110 1.2869
3 1.3264 1.8261 1.3556 1.2159
Delta 0.0702 1.0385 0.1005 0.2031
Rank 4 1 3 2
17

18. Root mean square surface roughness parameter(Rq) (Cont.)
 Due to the deviation of feed rate, the
value of Rq varies; but depth of cut has
slight influence
 When the depth of cut is increasing value of
Rq does not change like feed rate
18
Depth of Cut
Feed
1.501.251.000.750.50
0.175
0.150
0.125
0.100
>
–
–
–
–
–
< 0.6
0.6 0.9
0.9 1.2
1.2 1.5
1.5 1.8
1.8 2.1
2.1
Rq
Contour Plot of Rq vs Feed, Depth of Cut
0.5
1.0
.0 5
1 0.
.1 5
10. 52
001.0
5.1
0
.10 50
10. 52
.170 5
2.0
qR
deeF
tuCfohtpeD
urface Plot of Rq v Feed, Depth ofS Cuts

19. Ten point mean roughness parameter(Rz)
 With the development of the cutting depth,
the mean of Rz increases at a continual rate
 Cutting speed is the most insignificant
among all four factors
Table 4.3.1
Response Table for mean of means of average maximum height
(Rz). [Smaller is better]
Level Cutting speed Feed rate Depth of cut
Cutting
condition
1 4.412 2.980 4.215 5.019
2 4.536 4.831 4.561 4.402
3 4.655 5.792 4.827 4.182
Delta 0.243 2.812 0.612 0.838
Rank 4 1 3 2
19

20. Ten point mean roughness parameter(Rz) (Cont.)
 The depth of cut scarcely influences the
average maximum height value; increased
feed rate has important influence
 The waviness created at some points is due
to the interaction between feed and depth
of cut
20
Depth of Cut
Feed
1.501.251.000.750.50
0.175
0.150
0.125
0.100
–
–
–
–
–
< 2
2 3
3 4
4 5
5 6
6 7
Rz
Contour Plot of Rz vs Feed, Depth of Cut
0.5
1.0
2
4
6
1. 50 2
0.100
5.1
0
. 00 51
1. 50 2
0.175
6
8
zR
deeF
tuCfohtpeD
urface Plot ofS Rz v Feed, Depth of Cuts

21. Maximum height of the profile parameter(Rt)
 Cutting condition has shown contradictory
but regular changes in manipulating the
mean of Rt
 Depth of cut is third most significant factor
among the four control factors
Table 4.4.1
Response Table for mean of means of the maximum height of
the surface (Rt) [Smaller is better]
Level Cutting speed Feed rate Depth of cut
Cutting
condition
1 6.035 4.141 5.657 6.758
2 6.173 6.221 6.075 5.869
3 6.014 7.860 6.491 5.596
Delta 0.160 3.719 0.835 1.162
Rank 4 1 3 2
21

22. Maximum height of the profile parameter(Rt) (Cont.)
 The average maximum height value does
not get much effect by cutting depth, feed
rate increases the parameter value
 Feed rate has much more significant affect
on Rt than depth of cut
22Depth of Cut
Feed
1.501.251.000.750.50
0.175
0.150
0.125
0.100
>
–
–
–
–
–
–
< 3
3 4
4 5
5 6
6 7
7 8
8 9
9
Rt
Contour Plot of Rt vs Feed, Depth of Cut
.0 5
.01
4
6
8
. 5210
01.0 0
5.1
0
501.0
. 5210
51.0 7
8
10
tR
deeF
tuCfohtpeD
urface Plot oS Rt vf Feed, Depth of Cuts

23. Maximum profile peak height(Rp)
 Increase in cutting speed from the lowest
to highest value results in a slight
increase in the mean of Rp
 Feed rate has the highest value of delta
proving feed rate is the leading factor among
four other factors
Table 4.5.1
Response Table for mean of means of the maximum profile
peak height (Rp). [Smaller is better]
Level Cutting speed Feed rate Depth of cut
Cutting
condition
1 2.597 1.641 2.375 3.020
2 2.807 2.861 2.787 2.611
3 2.825 3.727 3.068 2.598
Delta 0.228 2.086 0.693 0.422
Rank 4 1 2 3
23

24. Maximum profile peak height(Rp) (Cont.)
 Maximum height value does not quite
change with changes referred to depth of
cut but feed rate value do
 Profile peak value increases when the feed
rate is high
24Depth of Cut
Feed
1.501.251.000.750.50
0.175
0.150
0.125
0.100
>
–
–
–
–
< 1
1 2
2 3
3 4
4 5
5
Rp
Contour Plot of Rp vs Feed, Depth of Cut
50.
1.0
1.0
52.
4.0
52.10
000 1.
5.1
0
0 051.
52.10
570.1
4.0
5 5.
pR
deeF
tuCfohtpeD
urface Plot of Rp v dFeeS , Depth of Cuts

25. Maximum profile valley depth(Rv)
 Increase in cutting speed from the lowest to
highest value results in a slight increase in
the mean of Rv
 Cutting speed has the least effect on the
average surface roughness value.
Table 4.6.1
Response Table for mean of means the maximum profile valley
depth (Rv). [Smaller is better]
Level Cutting speed Feed rate Depth of cut
Cutting
condition
1 1.810 1.339 1.896 1.987
2 1.876 1.970 1.824 1.784
3 1.828 2.205 1.795 1.743
Delta 0.067 0.865 0.101 0.244
Rank 4 1 3 2
25

26. Maximum profile valley depth(Rv) (Cont.)
 The lower feed rate is associated with lower
surface roughness and the upper portion of
the plot represents higher values of Rv.
 The value of Rv is increasing exceedingly
when the feed rate is escalated
26Depth of Cut
Feed
1.501.251.000.750.50
0.175
0.150
0.125
0.100
>
–
–
–
–
< 1.0
1.0 1.5
1.5 2.0
2.0 2.5
2.5 3.0
3.0
Rv
Contour Plot of Rv vs Feed, Depth of Cut
50.
1.0
1
2
0.125
0.10 0
5.1
0
051.0
0.125
571.0
3
vR
deeF
tuCfohtpeD
urface Plot of Rv v dFeeS , Depth of Cuts

27. Conclusion
 The cutting speed has insignificant impact on the studied surface roughness parameters
among all the four control factors.
 Feed rate expressed itself as the most dominant control factor to determine a better surface
roughness parameter.
 Depth of cut has less effect on the surface roughness parameters compared to feed rate.
 In cutting condition, MQL emerged as the major cooling condition compared to other two
conditions which are dry and flood condition.
27