Reducing micro-machining errors during electric discharge machining of titanium alloy using nonionic liquids

Abstract

The study employs nonionic liquids with cryogenically treated tool electrodes to investigate micro-machining errors. An extensive Full Factorial-based experimental campaign is executed involving unmodified process: 12 experiments (kerosene dielectric as baseline for improvement) and modified process: 108 experiments. In modified process, three distinct nonionic liquid types, their concentration, cryogenically treated electrodes, and pulse ON:OFF time are used. All the nonionic liquid-mixed dielectrics have shown noticeable improvement in terms of achieving low machining errors as compared to the conventional dielectric system. In unmodified process, the aluminum and graphite have produced micro machining errors 151.9 µm and 75 µm, respectively. The Desirability Function has recommended (experimentally validated 17.75 µm micro-machining error) the use of cryogenically treated graphite electrode with pulse ON:OFF time of 50:50 µSec and nonionic liquid S-60 with 25 g/L concentration to achieve minimum micro-machining errors with the highest desirability index of 98.60%.