A Comparative Study of EDD and PM-EDD in Producing Holes in Inconel 718 Alloy

Abstract

In recent times, aerospace, chemical industries and nuclear plant have usually used Inconel 718 alloy because of its excellent mechanical and chemical properties at elevated temperatures. It falls under the category of difficult-to-cut materials due to its high toughness, poor thermal conductivity and high hardness. The set-ups for electric discharge drilling (EDD) and powder-mixed electric discharge drilling (PM-EDD) were developed, and experiments were conducted on them separately. This research shows a comparative study amid producing holes by EDD and PM-EDD in Inconel 718 alloy workpiece with copper tool electrode. SiC was used as an abrasive powder because of its better thermal conductivity in order to get properly mixed with dielectric in a separate tank. Output response was assessed in the form of material removal rate, under the influence of discharge current, duty factor, pulse-on-time and tool speed, as the input parameters.

The state of the art of electrical discharge drilling: a review

“…Powders with specific materials are added to the dielectric fluid to improve its breakdown characteristic. The series discharges caused by the powders enlarge the sparking gap, which can facilitate the removal of the debris and stable machining process [142][143][144]. The added powder would be energised and move in a zigzag fashion during the pulse-on time.…”