Comparative study on machinability improvement in hard
turning using coated and uncoated carbide inserts: part II
modeling, multi-response optimization, tool life, and economic
aspects
Ramanuj Kumar
1
•
Ashok Kumar Sahoo
1
•
Purna Chandra Mishra
1
•
Rabin Kumar Das
1
Received: 23 March 2017 / Accepted: 16 January 2018 / Published online: 9 March 2018
Ó Shanghai University and Springer-Verlag GmbH Germany, part of Springer Nature 2018
Abstract The present study focused on mathematical
modeling, multi response optimization, tool life, and eco-
nomical analysis in finish hard turning of AISI D2 steel
((55 ± 1) HRC) using CVD-coated carbide (TiN/TiCN/
Al
2
O
3
) and uncoated carbide inserts under dry environ-
mental conditions. Regression methodology and the grey
relational approach were implemented for modeling and
multi-response optimization, respectively. Comparative
economic statistics were carried out for both inserts, and
the adequacy of the correlation model was verified. The
experimental and predicted values for all responses were
very close to each other, implying the significance of the
model and indicating that the correlation coefficients were
close to unity. The optimal parametric combinations for
Al
2
O
3
coated carbide were d1–f1–v2 (depth of cut = 0.1
mm, feed = 0.04 mm/r and cutting speed = 108 m/min), and
those for the uncoated tool were d1–(0.1 mm)–f1 (0.04
mm/r)–v1 (63 m/min). The observed tool life for the coated
carbide insert was 15 times higher than that for the
uncoated carbide insert, considering flank wear criteria of
0.3 mm. The chip volume after machining for the coated
carbide insert was 26.14 times higher than that of the
uncoated carbide insert and could be better utilized for
higher material removal rate. Abrasion, diffusion, notch-
ing, chipping, and built-up edge have been observed to be
the principal wear mechanisms for tool life estimation. Use
of the coated carbide tool reduced machining costs by
about 3.55 times compared to the use of the uncoated
carbide insert, and provided economic benefits in hard
turning.
Keywords Machinability Á Hard turning Á Regression Á
Grey relational analysis Á Tool life Á Economic analysis
1 Introduction
In recent decades, innovation of new technology in the
field of machining of hardened steels has played a vital role
in various manufacturing industries towards the improve-
ment of product quality. Manufacturers are continuously
focusing on cost reduction, good-quality finished products,
and operation at optimized cutting and environmental
conditions, such that it is suitable for manufacturing
industries to obtain desired outputs. To achieve the target
of good surface finish on hardened materials with cost
effectiveness, a new evolving technology called hard
turning, which has slowly replaced the conventional
cylindrical grinding operations, should be implemented.
Hard turning is a process used to produce a cylindrical
surface of a hardened piece having a hardness value
between 45 HRC and 65 HRC using a single point cutting
edge of the tool [1–5]. Hardened steel has been utilized in
various industries, like the aerospace industries, automo-
bile industries, and highly precise machine tool manufac-
turing industries. Hard turning is already proving its
importance in a major way, with significant evolution in its
cutting tool technology and lubrication techniques. The
major hurdle faced in machining of extremely hard metal is
tool wear, as cutting tools are very expensive, and therefore
affect the overall cost of production when generation of
quality products is the goal. With recent advances in tool
material and the coating technology of different cutting
& Ashok Kumar Sahoo
aklala72@gmail.com
1
School of Mechanical Engineering, Kalinga Institute of
Industrial Technology, Bhubaneswar-24, Odisha, India
123
Adv. Manuf. (2018) 6:155–175
https://doi.org/10.1007/s40436-018-0214-0
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