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Abstract
The present investigation presents a study of sinking electric discharge
machining assisted by magnetic field process with different features. In this
work, a copper and graphite electrodes are proposed as electrode tools in
electric discharge machining assisted by magnetic field process for high
performance alloy, armoured steel (500HV). The working parameters,
namely, peak current, magnetic flux density, duty factor and dielectric fluid
pressure are investigated to study performance criteria, i.e., metal removal
rate (MRR), tool wear rate (TWR) and surface roughness (Ra, Rz).
An experimental study is presented through performing series of designed
experiments. For this purpose, a designed and fabricated test rig was used.
The experimental results are statistically analyzed and mathematically
modeled through response surface methodology (RSM).
The results reveal that using EDM assisted by magnetic field through copper
and graphite electrodes for armoured steel (500HV) is an economical
method. It saves the expenses of the EDM process and adds a new
controlling parameter, magnetic flux density. The results reveal that MRR,
TWR and surface roughness (Ra, Rz) are significantly improved with the
increase of magnetic flux density when using both electrodes. The dielectric
fluid pressure has a moderate effect when machining by EDM assisted by
magnetic field for the two electrodes. Also, the results revealed that EDM
assisted by magnetic field could facilitate the expulsion of machining debris
to reduce the probability of abnormal electrical discharge, so the surface
cracks were relatively less on the machined surface.