S. MANOJ, V. C. S. GANDHI: INVESTIGATION OF A TOOL AND WORKPIECE MACHINED ...
171–175
INVESTIGATION OF A TOOL AND WORKPIECE MACHINED
USING A NICKEL-NANOCOATED INSERT
RAZISKAVA OBRABE ORODJA IN OBDELOVANCA ZARADI
MEHANSKE OBDELAVE Z VLO@KOM Z Ni-NANOPREVLEKO
Sureshkumar Manoj1, Veeramalai Chinnasamy Sathish Gandhi2
1TRP Engineering College (SRM Group), Department of Mechanical Engineering, Trichy, 621105, Tamilnadu, India
2University College of Engineering Nagercoil, Department of Mechanical Engineering, (A Constituent College of Anna University, Chennai)
Nagercoil 629004, Tamilnadu, India
mailmanojinbox@gmail.com
Prejem rokopisa – received: 2017-06-11; sprejem za objavo – accepted for publication: 2017-08-03
doi:10.17222/mit.2017.071
Most of the industrial components are machined using the turning operation. In order to sustain in the global market, the
industries strive to produce precision components. One such step towards attaining precision components is the introduction of
inserts. Inserts are detachable components, brazed to the working tool. The most commonly used inserts are cemented carbide
inserts. However, after a few machining operations, these inserts are subjected to wear. The life of the inserts is thus reduced by
the wear. In order to reduce the wear and improve the life of a tool, the inserts are coated. Coated inserts are proven to improve
the mechanical properties of machined workpieces. Nevertheless, the problem still persists while machining hard-to-machine
materials. Therefore, there is a need for an alternate approach. In that case, nanomaterials can be applied to improve the proper-
ties and tool life. In nanomaterials, particles with a size of 10–9 m are used, exhibiting strong bonding along the boundaries. Due
to this property, the material may resist the wear, improve the tool life and mechanical properties of machined materials. In the
present work, cemented carbide inserts were coated with a nickel nanomaterial using the physical vapour deposition (PVD)
technique, as nickel exhibits a high wear resistance and it is a hard material. The results showed that nickel-nanocoated inserts
improve the tool life by reducing the wear of the inserts and the surface roughness of a machined workpiece as compared with
uncoated inserts.
Keywords: inserts, coatings, nickel (Ni), nanomaterials, SEM, Taguchi method
Ve~ina industrijskih komponent je mehansko obdelanih s stru`enjem ali rezkanjem. Zato, da bi se dolo~eno podjetje obdr`alo na
globalnem trgu, mora skrbeti za ~imve~jo natan~nost svojih izdelkov. Eden od na~inov je uvajanje ~im bolj{ih vlo`kov (rezalnih
plo{~ic) za mehansko obdelavo. Vlo`ki so lo~ljive komponente, ki so obi~ajno mehansko pritrjene na delovno orodje (no`).
Najbolj pogosto uporabljene rezalne plo{~ice so izdelane iz karbidnih trdin. Le-te se med mehansko obdelavo obrabljajo. Zaradi
mehanske obrabe je njihova doba trajanja skraj{ana. Da bi zmanj{ali obrabo rezalnih plo{~ic in podalj{ali njihovo dobo trajanja,
so le-te obi~ajno prevle~ene s trdo prevleko. Prevle~ene rezalne plo{~ice dokazano izbolj{ajo mehanske lastnosti obdelovanca.
Vendar problemi {e ostajajo, ~e je potrebno mehansko obdelovati trde in te`ko obdelovalne materiale. Zato so potrebni alterna-
tivni pristopi z uporabo nanoprevlek. Nanomateriali so sestavljeni iz delcev reda velikosti 10–9 m, ki imajo mo~no medsebojno
vez. Zaradi tega se lahko mo~neje upirajo obrabi, kar podalj{a `ivljenjsko dobo rezalnega orodja in izbolj{a mehanske lastnosti
obdelovancev. V pri~ujo~em delu avtorji opisujejo uporabo rezalnih plo{~ic iz karbidne trdine, ki so bile prevle~ene s prevleko
iz nano Ni. Prevleka je bila izdelana s fizikalnim postopkom nana{anja iz parne faze (PVD; angl.: Physical Vapor Deposition).
Ni-nanoprevleka je trda in zato visoko obrabno odporna. Rezultati raziskave so pokazali, da imajo rezalne plo{~ice prevle~ene z
Ni-nanoprevleko precej bolj{o odpornost proti obrabi, v primerjavi z neprevle~enimi rezalnimi plo{~icami, kar precej podalj{a
njihovo dobo trajanja in zmanj{a hrapavost obdelovanca.
Klju~ne besede: rezalne plo{~ice, prevleke, nikelj (Ni), nanomateriali, SEM, Taguchi metoda
1 INTRODUCTION
Machining is a process where raw materials are made
into a desired product using a controlled process of
material removal. Turning is a type of the machining
process where a non-rotary tool-bit-type cutting tool
defines the helical tool path.1 In earlier days, a turning
operation was carried out manually. It required highly
skilled labour and close monitoring. Constant super-
vision was required. Later this type of turning was
replaced with computer numerical control lathes. To
make their name short, they were called CNC lathes and
they are still widely used nowadays. The speed, feed and
depth of a cut are the three prime machining parameters
of a turning operation.2 The speed generally refers to the
workpiece and spindle speed. The unit of measurement is
revolution per minute (min–1).
The feed is defined as the relative velocity, at which
the cutter advances the workpiece. Its direction vector is
perpendicular to that of the cutting speed. The unit of
feed rate is dependent on the workpiece and the motion
of the tool. Generally, the unit of feed in a turning ope-
ration is distance per spindle revolution (mm/min). The
feed rate is the most influential process parameter that
influences the metal-removal rate3 (MRR). The depth of
cut is the amount of material, which is removed in single
cut. The unit of measurement is millimetre (mm).
Nowadays inserts are widely used for turning operations.
Inserts are detachable cutting tips. They are not brazed or
welded to the tool. Inserts are normally indexable as they
Materiali in tehnologije / Materials and technology 52 (2018) 2, 171–175 171
UDK 620.1:620.178.16:539.92 ISSN 1580-2949
Original scientific article/Izvirni znanstveni ~lanek MTAEC9, 52(2)171(2018)
can be flipped or rotated without affecting the overall
geometry of the tool. The time wasted for set-up
changes, new input values for CNC lathes and tool
grinding can be avoided with the inserts that are perio-
dically changed.
An experimental investigation conducted in the
machining of the AISI 310 austenitic stainless steel with
titanium-carbide cutting tools showed the effects of
machining parameters on the built-up-layer (BUL) and
built-up-edge (BUE) formation and the wear behaviour
of the cutting tools.4 The highest accumulations of the
BUL and the BUE were observed at low cutting speed,
feed rate and cutting depth. Researches revealed that a
multilayer TiN/TiCN/Al2O3/TiN-coated insert performed
better than the uncoated inserts.5 Also, a carbide-coated
insert exhibits machinability with a better surface finish.6
When the optimum condition is chosen, it lowers the
flank wear and surface roughness with a higher MRR.7
The application of nanotechnology in the coating
field proved to be profitable. The materials exhibit new
behaviours and properties at a nanoscale. The range of
nanoscale varies from 1 nm to 100 nm. It takes skill to
utilize these nanoprinciples. A sincere effort is needed to
manipulate and control nanomaterials in a better way.
The properties of materials such as electrical conduc-
tivity, heat conductivity, magnetic properties, hardness,
etc., can be improved by varying the size of the particles
within the nanoscale. Surface areas of nanoscale
materials are larger when compared with larger-scale
materials of similar volumes. The surface interacting
with the other materials around them is large in the case
of nanoscale materials. A better tool life is achieved
when adaptive nano-multilayered coating is done.8
From the literature study, it was evident that the tool
life, wear resistance and hardness can be improved by
coating the tool and inserts.9 Also, nanomaterials have
low friction and good wear resistance10 as compared to
ordinary coatings. It was also seen from the literature
that silicon, titanium and zirconium coatings are pre-
sently used to improve the life of inserts. Nickel is a
harder material, whose particles, at a nanoscale, exhibit
better mechanical properties than those of SiO2, Ti or Zr.
2 EXPERIMENTAL PART
The experimental work was carried out in a
computer-numerical-control (CNC) lathe machine.11 The
CNC lathe, in which the experiments were carried out, is
shown in Figure 1.
The CNMG 120408 tool (C-shape, N-clearance
angle, M-tolerance, G-groove/hole) was chosen as the
insert. The workpiece machined using CNMG inserts
exhibited a lower surface-roughness value than TNMG
and WNMG inserts. Then the machining was carried out
under different cutting conditions. During the machining,
the machining time was noted.
The inserts were then coated with the nickel nanoma-
terial using the physical-vapour-deposition technique12
(PVD). The PVD technique is preferred over CVD since
PVD coatings are thin but still tougher and smoother.
Various properties of the nickel nanomaterial are shown
in Table 1.
Table 1: Properties of nickel nanoparticles13,14
Chemical symbol Ni
CAS No. 7440-02-0
Group 4
Electronic configuration (Ar) 3d8 4s2
Molar mass 58.69 g/mol
Melting point 1453 °C
Boiling point 2732 °C
The radio-frequency (RF) sputtering technique,
which is one of the physical-vapour-deposition pro-
cesses, was used for applying nanomaterials on the
inserts. The RF sputtering technique was used as it
effectively and evenly applies the material over the
substrate. Table 2 shows the experimental data for the
turning operation.
Table 2: Experimental data for the turning operation
Process parameter Level 1 Level 2 Level 3
Speed in min–1 1200 1600 2000
Feed in mm/rev 0.18 0.24 0.28
Depth of cut in mm 0.4 0.8 1.2
The Taguchi method was used for determining the
number of experiments.15 The Taguchi method provides
an experimental design, involving orthogonal arrays, to
organize the parameters that affect the process and its
different levels. Since factorial design consumes more
time and resources, the L9 orthogonal array is a more
effective method than factorial design. Unlike the
factorial design where all possible combinations are
tested, only pairs of combinations are tested with the
Taguchi method. This helps us determine the factors that
affect the product quality using the minimum number of
experiments. So, it saves time and resources. Here, the
Taguchi L9 orthogonal array is chosen, as there are three
S. MANOJ, V. C. S. GANDHI: INVESTIGATION OF A TOOL AND WORKPIECE MACHINED ...
172 Materiali in tehnologije / Materials and technology 52 (2018) 2, 171–175
Figure 1: CNC lathe
parameters and three levels. Table 3 shows the experi-
mental design using the L9 orthogonal array.
Table 3: Experimental design using L9 orthogonal array
Experiment
No.
Levels
Speed in min–1 Feed inmm/rev
Depth of cut in
mm
1 1200 0.18 0.4
2 1200 0.24 0.8
3 1200 0.28 1.2
4 1600 0.18 0.4
5 1600 0.24 0.8
6 1600 0.28 1.2
7 2000 0.18 0.4
8 2000 0.24 0.8
9 2000 0.28 1.2
A surface-roughness tester was used to measure the
surface-roughness value and a SEM test was conducted
to study the wear that occurred on the coated and
uncoated inserts.
3 RESULTS AND DISCUSSION
The experiments were chosen using the Taguchi L9
orthogonal array and the turning operation was con-
ducted in a CNC lathe with a CNMG insert coated with
nickel nanoparticles as shown in Table 4.
Table 4: Surface-roughness comparison between coated (nickel-nano-
coated) and uncoated inserts
S. No. Speed inmin–1
Feed in
mm/rev
Depth of
cut in mm
Surface roughness
in microns
Coated Uncoated
1 1200 0.18 0.4 0.8 1.6
2 1200 0.24 0.8 1.6 3.2
3 1200 0.28 1.2 3.2 6.3
4 1600 0.18 0.4 0.4 0.8
5 1600 0.24 0.8 1.6 3.2
6 1600 0.28 1.2 6.3 12.5
7 2000 0.18 0.4 0.8 1.6
8 2000 0.24 0.8 1.6 3.2
9 2000 0.28 1.2 6.3 12.5
From the above Table 4 we can see that the surface
roughness increases with increases in the speed, feed and
depth of cut. It is evident that the surface roughness of
the workpiece machined with the nickel-nanocoated
inserts is far better compared with the uncoated inserts. It
is observed that for the coated inserts at a speed of
1600 min–1, feed rate of 0.18 rev/mm and depth of cut of
0.4 mm, the surface roughness is 0.4 microns. For the
uncoated inserts, the surface roughness is 0.8 microns. It
is seen that the surface roughness of the coated inserts is
lower by 50 % when compared with the uncoated inserts.
This is the minimum surface-roughness value obtained.
So, the corresponding process parameters are considered
to be the optimum conditions.
Nickel nanocoating withstands the temperature
during the machining. Nickel nanocoating reduces the
temperature generated during the machining. The nickel
nanocoating on the inserts not only improved the surface
roughness but also improved the wear resistance of the
inserts. A scanning electron microscope (SEM) analysis
of the tool inserts was done. Both the uncoated insert and
the nickel-nanocoated insert were studied with the SEM
analysis. Transmission electron microscopy (TEM),
X-ray diffraction (XRD) and energy-dispersive X-ray
analysis (EDX) are the other methods that can be used to
study the wear surface of a tool. SEM images of the
coated and uncoated inserts at various magnification
levels are shown in Figures 2a, 2b, 2c and 3a, 3b, 3c.
The SEM images of the uncoated insert show that
crater wear occurs on the rake face of the tool, which
causes a change in the tool-chip interface geometry. This
affects the cutting process. The major factors that cause
crater wear are the temperature at the tool-chip interface
and the chemical magnetism between the workpiece
material and the tool. It is thus tri-biochemical wear due
S. MANOJ, V. C. S. GANDHI: INVESTIGATION OF A TOOL AND WORKPIECE MACHINED ...
Materiali in tehnologije / Materials and technology 52 (2018) 2, 171–175 173
Figure 2: a), b) and c) SEM images of the uncoated insert at different
levels of zoom
to the chemical affinity between the cutting-tool mate-
rials and the workpiece materials. The life of the tool is
also reduced. Figures 3a, 3b and 3c show SEM images
of the nickel-nanocoated insert at different levels of
zoom.
Figures 3a, 3b and 3c shows that the crater-wear
formation is smaller. The nickel coating binds well to the
tungsten-carbide substrate and no peel off is seen. There-
fore, the life of the insert is improved due to a higher
wear resistance.
4 CONCLUSIONS
A nickel nanomaterial was successfully applied over
a tungsten-carbide insert using RF sputtering of the PVD
technique. The number of experiments was chosen using
the Taguchi method. Then the workpiece was machined
with both uncoated and nickel-nanocoated tool. SEM
images of the uncoated and nickel-nanocoated inserts
were studied. From the above discussion, it is concluded
that:
• the workpiece machined with the nickel-nanocoated
insert exhibits a low surface roughness when com-
pared with the uncoated insert;
• the uncoated carbide insert wears out more quickly
than the nickel-nanocoated insert; so the nickel nano-
coating improves the life of the insert;
• the optimum parameters for the minimum surface-
roughness value are obtained.
5 REFERENCES
1 G. Bartarya, S. K. Choudhury, State of the art in hard turning, Inter-
national Journal of Machine Tools & Manufacture, (2012) 53, 1–14,
doi:10.1016/j.ijmachtools.2011.08.019
2 B.Varaprasad, C.Srinivasa Rao, P. V. Vinay, Effect of Machining
Parameters on Tool Wear in Hard Turning of AISI D3 Steel, 12th
Global Congress On Manufacturing And Management, 97 (2014),
338–345, doi:10.1016/j.proeng.2014.12.257
3 B. Rajendra, D. Deepak, Optimization of Process Parameters for
Increasing Material Removal Rate for Turning Al6061 Using S/N
ratio, International Conference on Emerging Trends in Engineering,
Science and Technology, 24 (2016), 399–405, doi:10.1016/j.protcy.
2016.05.055
4 M. B. Bilgin, Investigating the Effects of Cutting Parameters on the
Built-Up-Layer and Built-Up-Edge Formation during The Machining
of AISI 310 Austenitic Stainless Steels, Mater.Tehnol., 49 (2015) 5,
779–784, doi:10.17222/mit.2014.253
5 A. K. Sahoo, B. Sahoo, Experimental investigations on machinability
aspects in finish hard turning of AISI 4340 steel using uncoated and
multilayer coated carbide inserts, Measurement, 45 (2012),
2153–2165, doi:10.1016/j.measurement.2012.05.015
6 B. Pazhanivel, T. P. Kumar, G. Sozhan, Machinability and scratch
wear resistance of carbon-coated WC inserts, Materials Science and
Engineering B, 193 (2015), 146–152, doi:10.1016/j.mseb.2014.
12.006
7 N. Senthilkumar, T. Tamizharasan, Effect of Tool Geometry in
Turning AISI 1045 Steel: Experimental Investigation and FEM
Analysis, Arabian Journal for Science and Engineering, 39 (2014),
4963–4975, doi:10.1007/s13369-014-1054-2
8 A. Biksa, K.Yamamoto, G. Dosbaeva, S. C. Veldhuis, G. S.
Fox-Rabinovich, A. Elfizy, T. Wagg, L. S. Shuster, Wear behavior of
adaptive nano multilayered AlTiN/MexN PVD coatings during
machining of aerospace alloys, Tribology International, 43 (2010),
1491–1499, doi:10.1016/j.triboint.2010.02.008
9 A. Attanasioa, E. Ceretti, A. Fiorentinoa, C. Cappellinia, C. Giardi-
nib, Investigation and FEM-based simulation of tool wear in turning
operations with uncoated carbide tools, Wear, 269 (2010), 344–350,
doi:10.1016/j.wear.2010.04.013
10 L. H. Moreno, J. C. Ciacedo, F. Martinez, G. Bejarano, T. S.
Battaille, P. Prieto, Wear Evaluation of WC Inserts Coated with
TiN/TiAlN Multi nano layers, Journal of the Brazilian Society of
Mechanical Science and Engineering, 32 (2010), 2, doi:10.1590/
S1678-58782010000200003
11 E. Uhlmann, J. A. Oyanedel Fuentes, M. Keunecke, Machining of
high performance workpiece materials with CBN coated cutting
tools, Thin Solid Films, 518 (2009), 1451–1454, doi:10.1016/
j.tsf.2009.09.095
12 M. Nalbant, H. Gokkaya, I. Toktas, G. Sur, The experimental
investigation of the effects of uncoated, PVD- and CVD-coated
cemented carbide inserts and cutting parameters on surface
roughness in CNC turning and its prediction using artificial neural
networks, Robotics and Computer-Integrated Manufacturing, 25
(2009), 211–223, doi:10.1016/j.rcim.2007.11.004
13 A. Sohrabi, A. Dolati, M. Ghorbani, A. Monfared, P. Stroeve, Nano
mechanical properties of functionally graded composite coatings:
S. MANOJ, V. C. S. GANDHI: INVESTIGATION OF A TOOL AND WORKPIECE MACHINED ...
174 Materiali in tehnologije / Materials and technology 52 (2018) 2, 171–175
Figure 3: a), b) and c) SEM images of the nickel-nanocoated insert at
different levels of zoom
Electrodeposited nickel dispersions containing silicon micro- and
nano particles, Materials Chemistry and Physics, 121 (2010),
497–505, doi:10.1016/j.matchemphys.2010.02.014
14 M. Srivastava, J. N. Balaraju, B. Ravishankar, K. S. Rajam, Improve-
ment in the properties of nickel by nano-Cr2O3 incorporation,
Surface & Coatings Technology, 205 (2010), 66–75, doi:10.1016/
j.surfcoat.2010.06.004
15 N. Senthilkumar, T. Tamizharasan, V. Anandakrishnan, Experimental
investigation and performance analysis of cemented carbide inserts
of different geometries using Taguchi based grey relational analysis,
Measurement, 58 (2014), 520–536, doi:10.1016/j.measurement.
2014.09.025
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