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ScienceDirect
Materials Today: Proceedings 4 (2017) 10836–10844 www.materialstoday.com/proceedings
2214-7853 © 2017 Published by Elsevier Ltd.
Selection and Peer-review under responsibility of Advanced Materials, Manufacturing, Management and Thermal Science (AMMMT 2016).
AMMMT 2016
Evaluation of Electroless Nickel Poly alloys for Drilling of CFRP
Krishnakant Bhole
a
, J N Balaraju
b,
*, A. Anil Kumar
c
, U N Kempaiah
d
\
a
University Visvesvaraya College of Engineering, Bangalore University, Bangalore,560001, India. krishnakant.bhole@gmail.com
b
Surface Engineering Division, CSIR National Aerospace Laboratories, Bangalore 560017, Karnataka, India. jnbalraj@nal.res.in
c
Advanced Composites Division, CSIR National Aerospace Laboratories, Bangalore 560017, Karnataka, India. aanil@nal.res.in
d
University Visvesvaraya College of Engineering, Bangalore University, Bangalore,560001, India. unkemp@rediffmail.com
Abstract
Today even though composites have wide range of applications in aerospace and other industries, machining of composites is
still considered to be a difficult task. In this study, efforts are made to reduce drill bit wear characteristics during machining of
CFRP composite. Electroless coating method is used to coat nano-crystalline ternary Ni-W-P coating on HSS drill bits of
diameter 7mm, to carry out drilling operations on CFRP. The coatings are characterised by their morphology, composition,
structure, phase transformation behaviour and nano-hardness. By subsequent pre-treatment steps, Ni-W-P coatings are adhered
on HSS drill bits and coarse nodular structures were observed upon surface testing by using FESEM. About 14.5 weight % of W,
5.41 weight % of P with balance of Ni was observed in the compositional analysis of the deposit carried out by EDAX. With
constant feed and speed, drilling operation carried out on CFRP plate of thickness 2.5 mm and drill bit characteristics were
evaluated. HSS drill bits of type uncoated, Ni-W-P coated and heat treated were used for drilling CFRP plate. Drill bits tool wear
were examined by using Tool Makers Microscope. The drilling operation is carried out to drill 100 holes on CFRP plate by all
types of drill bits and the drill bits were examined at every 20 intervals of drilling. It was found that Ni-W-P coated drill bits have
shown about 60% reduction (0.2mm less) in chisel edge wear, about 40% (0.1mm) lower wear on cutting edge and about 60%
(0.5mm) less wear on flank surface compared to uncoated and heat treated drill bits. Based on the results obtained in this study,
electroless ternary Ni-W-P coating seems to be most likely material which enhances the tool life and gives better quality
machining.
© 2017 Published by Elsevier Ltd.
Selection and Peer-review under responsibility of Advanced Materials, Manufacturing, Management and Thermal Science
(AMMMT 2016).
Keywords: Electroless nickel; CFRP Drilling; Drill bit wear.
* Corresponding author. Tel.: +0-802-508-6239; fax: +0-802-521-0113.
E-mail address: jnbalraj@nal.res.in