Powder mixed electrical discharge machining of oil hardened non shrinking steel die steel – Optimization and investigation

Abstract

Powder Mixed Electrical Discharge Machining process is commonly used to machine hard to cut materials such as OHNS steel which are used to make gauges where precise machining is required. Precise machining requires proper control of parameters and obtaining the most suitable set of parameters. Hence, this work deals with varying the input parameters over a specified range and studying there effect on the responses such as Material Removal Rate (MRR) and Surface Roughness (SR) which are the critical responses that govern productivity and product quality. The input parameter such as Pulse ON time (T on), Pulse OFF time (T off) and Powder concentration was varied. The Response Surface Methodology was used to select the critical set of parameters and Analysis by variance (ANOVA) analysis was used to identify the most influential parameter for the responses. FESEM was recorded which showed better surface with reduced crack at Pulse ON time (T on) = 35 micro seconds, Pulse OFF time (T off) = 7 micro seconds and Powder Concentration of 4 gm/litre.