Environmental impact, personnel health and operational safety aspects of electric discharge machining a review

1. Review Article
Proc IMechE Part B:
J Engineering Manufacture
2015, Vol. 229(9) 1481–1491
Ó IMechE 2014
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DOI: 10.1177/0954405414543314
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Environmental impact, personnel
health and operational safety aspects
of electric discharge machining:
A review
Janak B Valaki1,2
, Pravin P Rathod3
and Bharat C Khatri1,4
Abstract
Electrical discharge machining has emerged as the most popular non-conventional material removal process due to its
novel variants, inherent process capability, and suitability for hybridization with other conventional and non-conventional
material removal processes. However, high specific energy consumption, self-sacrificial electrode, hazardous emissions,
toxic dielectric waste and sludge generation make this process one of the most unsustainable machining processes.
Increased market competitiveness and requirement to comply with ISO 14000 standards demanded to implement sus-
tainable manufacturing practices for short- and long-term business growth. In this article, the authors have reviewed the
research work done in three of the sustainability indicators for the electrical discharge machining process, such as envi-
ronmental impact, personnel health and operational safety. Modes of dielectric supply such as wet, dry and near dry have
a paramount influence on the said sustainability indicators. Research works related to each indicator have been reviewed
for the three modes of dielectric supply. This review provides a basis for understanding the current status of research
activities for electrical discharge machining in the context of sustainability indicators. Future research needs have been
discussed to make electrical discharge machining a more sustainable metal removal process.
Keywords
Sustainable manufacturing, environmental impact, personnel health, operational safety, wet, dry and near-dry electrical
discharge machining, sustainable electrical discharge machining
Date received: 14 November 2013; accepted: 19 May 2014
Introduction
Electric discharge machining (EDM) is the most widely
practiced non-conventional material removal process
and enjoys more than 7% market of worldwide sales of
total machine tools.1
In this process, high-frequency
electric sparks cause decomposition of the dielectric
media, which eventually generates intense temperatures
of the order of 8000–12,000 K to melt and vaporize the
work material.2
Uniqueness of the process lies in the fact
that the material is removed accurately and precisely at
extremely high temperature. Controlled material erosion
makes it possible to generate dimensionally and geome-
trically accurate profiles on difficult-to-cut materials.
EDM is basically used for the manufacture of molds,
dies, punches, cutting tools and surface texturing of
steel rolls.3
However, with developments of various var-
iants of the process, its applications are likely to be
extended to surface alloying and texturing, and manu-
facturing of components for electronics, medical and
surgical, optical, jewelry, automotive and aeronautical
industries.4
The dielectric fluid plays extremely important func-
tions regarding productivity, cost and quality of the
machined parts.4
Functions performed by dielectric
fluids in EDM process are grouped into primary and
secondary functions as listed below.
1
Mechanical Engineering Department, School of Engineering, RK
University, Rajkot, India
2
Mechanical Engineering Department, Government Engineering College,
Bhavnagar, India
3
Mechanical Engineering Department, Government Engineering College,
Bhuj, India
4
Mechanical Engineering Department, L. D. Engineering College,
Ahmedabad, India
Corresponding author:
Janak B Valaki, Mechanical Engineering Department, Government
Engineering College, Bhavnagar, Gujarat 364 001, India.
Email: janakvalaki@gmail.com
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