Electrical Discharge Drilling of D3 Die Steel using Air Assisted Rotary Tubular Electrode

This articles focus on developing a hybrid EDM process using liquid cum gaseous dielectrics to study its influence on tool wear rate (TWR), material removal rate (MRR) and over cut (OC) of workpiece. The compressed air flow through a rotary tubular electrode removed and flushed out the debris from the working gap and hence it improves the flushing efficiency and stability of the process. This study describe the experimental investigation of formation of holes in D3 die steel workpiece with conventional EDM and air assisted electrical discharge drilling (AAEDD). An attachment was designed and developed to carry out AAEDD process on the existing EDM machines. The entire arrangement is in the form of an independent unit which could be attached to the existing EDM machine. The influence of various machining parameters such as discharge current, pulse on time, duty cycle and tool speed on output response viz., MRR, TWR and OC have been studied. Under the same machining condition, high MRR and low TWR as well as OC obtained when AAEDD machining was performed as compared to conventional EDM machining. Experimental findings suggested that supply of compressed air through rotary tubular electrode in die sinking electrical discharge drilling have a positive influence on MRR, OC and TWR. However, rotation of tool has a negative effect on OC. The SEM images of selected specimens were also in line with the experimental findings. (c) 2017 Elsevier Ltd. All rights reserved.