Electrochemical deep hole drilling in super alloy for turbine application

This investigation reports parametric study of electrochemical (DC mode) deep hole drilling in which acidified salt solution replaces acid electrolyte. Depth averaged radial overcut (DAROC) and mass metal removal rate (MRRg) are investigated. Through holes of 26 mm depth and diameters ranging from 2.054 to 4.128 mm are drilled in nickel-based super alloy. The results show that the best hole is obtained at a voltage of 9 V, tool feed rate of 0.9 mm/min, bare tip length of 0.9 mm, with an electrolyte composition of 12.5 wt.% NaCl and 2.5 wt.% HCl. These optimum parameters are used to drill holes of much higher aspect ratio, in super alloys.