International Journal of Engineering Trends and Technology (IJETT) – Volume 34 Number 6- April 2016
Study and analysis of Cryogenic Machining
of Hard Components and investigation of
tool wear
Ganesh B.Narkhede1,
Manoj Bauskar2
Assistant Professor and Mechanical Department and AISSMS College of Engineering, Pune
4o2 Pride Paradise,
Opp. Om Super Market,
Pune- 411 016.
Maharashtra, India.
S.No. 48/4, Ganeshnagar,
Vadgaonsheri,
Pune- 411 014
Maharashtra, India.
ABSTRACTIn Nuclear Engineering industries and
aerospace industries, surface finish and less tool
wear properties are very important, which requires
“Difficult to machine” materials like hast alloy,
wasp alloy, tool steels and carbides. Nuclear
engineering industries, aerospace industries, food
processing industries find wide applications of such
materials.
In such situations, we cannot
compromise quality with cost and to achieve such a
high quality surface finish, finishing or super
finishing processes are required due to which it's
cost goes up.
The present work explores the effect of
cryogenic coolant in the machining of hard
materials like Inconel 625 from an industrial
perspective with emphasis on higher productivity
and greater tool life as well as reliable performance
characteristics. This work is an attempt to analyze
the tool wear by controlling the variable parameters
such as speed, feed and depth of cut. The combined
effects of these parameters on tool wear are to be
established.
In cryogenic machining process a small jet of
liquid nitrogen to be injected onto the rake face of
cutting tool insert during the cutting process. After
machining, investigation of tool wear, surface finish
and cutting forces will be established.
KEYWORDS- Cryogenic technique, liquid
nitrogen, dry turning.
ISSN: 2231-5381
I. INTRODUCTION
In today’s competitive market if company
want to compete with others then the company must
adopt new techniques which may save the
production time and cost so that profit will increase.
Therefore it becomes necessary to introduce new
technology to become a leader in respective field. A
rapid adoption of newer and more cost effective
manufacturing techniques such as cryogenic
machining will be constantly required if
manufacturing operations are to remain competitive.
1. Turning Process:
The quality of surface is the widely used as index of
product quality and it is also crucial in functional
behavior of the products like machine tool parts,
dies etc. especially when they are the part of
assembly. Good finish turning process may even
eliminate the requirement of finishing operations
and can results in cost and time saving. Along with
if we understand the effects of speed, feed, depth of
cut and tool on the surface finish we can select the
proper parameters to get required surface finish in
minimum time. So it is important to study the effects
of these parameters for getting the required surface
finish. Turning process is categorized into two types
namely Dry turning and Wet turning according to
type of coolant used.
1.1 Wet turning:
Wet turning operations refer to the processes under
high-pressure with a water-soluble coolant. These
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International Journal of Engineering Trends and Technology (IJETT) – Volume 34 Number 6- April 2016
coolants helps to minimize the forces and to carry
away the chips produced during material removal
process. Generally, oils with a low flash point are
being used as coolants in wet turning to minimize
the hazards of fire. It is obvious that the costs related
to cutting fluids are frequently higher than those
related to cutting tools. Moreover, use of oil based
cooling lubricants causes the health and social
problems for workers. Therefore it becomes
necessary to introduce a new technology which is
environmentally sound and also carry the advantages
of conventional coolants.
1.2 Dry Turning:
In dry turning process, part is machined without use
of coolant, and because of this tool-chip interface
temperature remains extremely high. The localized
heating at the tool tip tends to aid in the cutting
action, since the heat generated at the tool tip begins
to anneal and soften the material just ahead of the
tool, making it easier to shear A measurement of the
hardness of the cut chips will show the values,
which are below one-half of the hardness of the
parent material, thereby demonstrating this scenario.
Fig. 1
Cryogenic techniques refer to the field related to
technology at deep freezing temperature generally
below -150 °C. Gases like helium, neon, nitrogen,
oxygen, argon, krypton, xenon, methane, ethane and
propane can be used as cryogenic fluids.
II. EXPERIMENTAL SET UP
1.Work piece and tool materials:
Table. 1.
Machine
HMT lathe NH22.
Work material
Inconel 625
Hardness of Inconel
45- 50 HRC
625
1.3 Cryogenic Machining
2. Properties of Inconel 625:
Many problems arises during machining are because
of the heat generation and the subsequent high
temperatures associated with it. Increased cutting
forces, excessive tool wear, poor surface finish, poor
dimensional stability, etc. are temperature dependent
side effects.
These all are interdependent and are the major
concerns during material removal process which can
be controlled by profuse cooling with conventionally
used coolant. But the problems associated with
conventionally used coolant are chemical breakage
at high temperatures environmental pollution which
may be hazardous to human being and recirculation
problem, and many more. These drawbacks can be
eliminated in cryogenic machining by using liquid
nitrogen as a coolant where maximum heat is carried
away from the cutting zone.
Cryogenic cooling is a method of cooling the
cutting tool and work piece during material removal
process with the help of liquid nitrogen coolant at
very low temperature (-150°C). A typical schematic
setup is shown in Fig given below.
ISSN: 2231-5381
Table . 2.
Values
Properties
Density
Melting Point
Thermal Conductivity
Specific Heat
Poisson’s ratio
Tensile Strength
3. Chemical Composition:
0.305 Kg/m³
2425°C
74 W/m°K
0.107 KJ/Kg°K
0.312
29.2 N/mm²
Table . 3.
N
i
5
8
C
r
2
0
M
o
810
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F
e
5
Al
Ti
C
0.
4
0.
4
0.
1
M
n
0.5
Si
Co
0.
5
0.
5
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International Journal of Engineering Trends and Technology (IJETT) – Volume 34 Number 6- April 2016
4. Cutting inserts grade and designations
Table. 4.
Insert
Coating Designation Manufacturer
2. AMPLIFIER AND COMPUTER SET-UP
FOR MEASURING FORCE COMPONENTS
Grade
Tungsten
Al2O3
TNMG
carbide
coating
160408
inserts
Kennametal
MS
Ke 5525
5. Input parameters and factors for comparison
between Dry & Cryogenic turning experiments
Table. 5.
Factor
Nomen
Fig. 3
Unit
clature
Values
1
2
3
Speed
N
m/min
50
125
200
Feed
F
mm/rev
0.04
0.08
0.12
DOC
DOC
Mm
0.2
0.3
0.4
3. ACTUAL CRYOGENIC MACHINING SETUP
III. EXPERIMENTAL CONFIGURATION FOR
MEASURING CUTTING FORCE
COMPONENTS
1. THE THREE COMPONENTS OF CUTTING
FORCES
Fz
Fig. 4
Workpiece
Fy
Dynamometer is a device used to measure
force, moment of force and power produced during
actual
Fx
cutting
operation.
Various
types
of
dynamometers are available in the market; In this
study we used Kistler dynamometer 9257B. It is
Piezo-electric dynamometer with large range (-5 KN
Fig. 2
Feed force (Fx), thrust force (Fy), Tangential force
(Fz) is schematically shown in above figure.
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to 5 KN) of direct measurement. This dynamometer
has great rigidity and consequently a high natural
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International Journal of Engineering Trends and Technology (IJETT) – Volume 34 Number 6- April 2016
frequency. Its high resolution enables the smallest
V. COMPARISON BETWEEN
dynamic changes in large forces to be measured.
The Turning experiments were performed
on constant interval of length. In both experiments
CRYOGENIC AND DRY TURNING
1. Comparison with respect to cutting force Fx.
we conducted turning for 40 mm of span. The
instantaneous
roughness
criteria
measurements
250
(arithmetic mean roughness, Ra) for each cutting
condition were obtained by means of Mitutoyo
Roughness Tester. The measurements were repeated
four times and the result is average of these values.
Sr. No
1
Cutting
Force 150
Fx(N)
100
IV. SUMMARY OF DESIGN OF
EXPERIMENTS
Table. 6.
Sr Nos
200
Type
Speed
Feed
DOC
Fx
Fy
Fz
Dry
50
0.04
0.2
161.1
212.
242
50
0
5
2
Cryo
50
0.04
0.2
36.44
79.2
3
Dry
50
0.08
0.3
172.9
4
Cryo
50
0.08
0.3
31.33
5
Dry
50
0.12
0.4
186.2
200
257.7
6
Cryo
50
0.12
0.4
37.8
64.8
122.5
7
Dry
125
0.04
0.2
188.1
200
227.3
8
Cryo
125
0.04
0.2
139.8
79.5
204.6
9
Dry
125
0.08
0.3
174.9
200
259.1
10
Cryo
125
0.08
0.3
135.6
76.6
241.4
1
142.2
3
4
5
6
7
8
Expt No
3
194.
2
268
9
Dry
Cryo
6
56.6
106
force FX in the Dry turning & Cryogenic turning.
5
6
11
Dry
125
0.12
0.4
200
200
278
12
Cryo
125
0.12
0.4
65.13
56.7
146
9
13
Dry
200
0.04
0.2
200
200
272.5
14
Cryo
200
0.04
0.2
155
95.3
202.5
15
Dry
200
0.08
0.3
200
200
312
16
Cryo
200
0.08
0.3
165.5
95.3
272.5
17
Dry
200
0.12
0.4
200
200
300.0
18
Cryo
200
0.12
0.4
146.2
89.1
Graph. 1. This graph shows the behavior of cutting
The overall reduction in cutting force is 45%.
2. Comparison with respect to feed force Fy.
250
200
150
Feed
100
Force
Fy (N) 50
0
188.2
1
2
3
4
5
6
7
8
Expt No
7
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9
Dry
Cryo
International Journal of Engineering Trends and Technology (IJETT) – Volume 34 Number 6- April 2016
Graph .2. This graph shows the behavior of the feed
force Fy in dry & cryogenic turning, in this the overall
reduction in the feed force is 61%.
A. TOOL LIFE:
Tool wear is a time dependent process. As cutting
3. Comparison with respect to thrust force Fz.
proceeds, the amount of tool wear increases
350
gradually. But tool wear must not be allowed to go
300
beyond a certain limit in order to avoid tool failure.
250
The most important wear type from the process
point of view is the flank wear & crater wear.
200
Following photographs elaborates how the crater
Fz
150
(N)
wear & flank wear are reduced in cryogenic
100
machining.
50
0
1 2 3 4 5 6 7 8 9
Dry
Expt No
Cryo
Graph. 3. This graph shows the behavior of the
thrust force Fz in dry & cryogenic turning, in this
overall reduction in the thrust force is 31%.
5. Comparison with respect to temperature
Dry Turning
180
160
140
120
100
Temp80
°C 60
40
20
0
1
2
3
4
5
6
7
Expt No
8
9
Dry
Cryo
Graph. 4. This graph shows the behavior of the
temperature in dry & cryogenic turning, in this the
Cryogenic
Turning
Fig .5. Crater Tool wear at speed 50 m/min, feed
0.04mm/rev, & DOC 0.2 mm
overall reduction in the temp is 80%.
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International Journal of Engineering Trends and Technology (IJETT) – Volume 34 Number 6- April 2016
Chip thickness 0.876 mm
Cryogenic Turning
Cryogenic Turning
Chip thickness 1.046 mm
Dry Turning
Dry Turning
Fig.6 . Flank Tool wear at speed 50 m/min, feed
Fig. 8. Chip tickness at Speed 50 m/min, Feed
0.04mm/rev, & DOC 0.2mm
0.12 (mm/rev), & DOC 0.4 mm
B. CHIP FORMATION
VI. CONCLUSION
Chip thickness 0.678 mm
The aim of this experiment was to convince the
industry of the merits of sustainable machining
technologies, taking into account the overall life
cycle of the CLFs. In this respect, cryogenic
machining is presented as a viable and sustainable
machining
Cryogenic Turning
technology
in
comparison
to
conventional machining. By performing number of
cryogenic and dry turning trials, we proved that
Chip thickness 1.140 mm
transitioning from oil based CLFs to LN used in
cryogenic machining is a positive move towards
more sustainable machining, which results in a
significant reduction in solid waste, water usage,
global warming potential, acidification, and in an
increased energy use for CLF production. Based on
Dry Turning
the comparative analysis, it is proved that cryogenic
Fig.7. Chip tickness at Speed 50 m/min, Feed 0.04
machining can be more energy efficient than
(mm/rev), & DOC 0.2 (mm)
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International Journal of Engineering Trends and Technology (IJETT) – Volume 34 Number 6- April 2016
conventional machining. This goes on account of
drastic reduction on cutting tools consumption.
The major conclusions from this investigation are
REFERENCES:
summarized as follows:
1] From the tool wear images, we can observe that
crater wear is more in dry turning, than cryogenic
turning.
2] Also, flank wear is more in dry turning, than
cryogenic turning.
3] Cryogenic turning improves the working life of
the cutting tool inserts, as wear in the cryogenic
turning is less than dry turning.
4] In chip thickness formation, the chip thickness is
more in dry turning than cryogenic turning.
5] Chip thickness is reduced by 28.99% in cryogenic
turning.
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