Improvement in Micro Feature Generation in ECDM Process With Powder Mixed Electrolyte

Abstract

Electrochemical discharge machining (ECDM), also known as spark assisted chemical engraving (SACE), is an effective micro-machining process for machining of electrically nonconducting materials. It involves melting and etching process under the high electrical discharge on the electrode tip during electrolysis that enables the ECDM process to machine very hard and non-conducting materials such as borosilicate glass, quartz, ceramics etc. efficiently and economically. In the current study micro holes are machined on borosilicate glass with an electrolyte mixed with graphite powder. The conductive graphite powder in electrolyte has shown improvement in machining with more quantity of spark during machining. The main parameters taken in the study are voltage, tool rotation and duty factor along with concentration of powder in electrolyte. The main output responses taken in the study are Material Removal Rate (MRR) and lower Radial Overcut (ROC) along the machined holes. A multi-objective optimization is carried out for higher MRR and lower ROC with Grey Relation Analysis (GRA) in order to obtain the best parameters combination. From the experimental study the optimum values of parameters for MRR and ROC are found to be, voltage of 40 V, Graphite powder concentration 1.25% by weight, duty factor 70% and tool rotation of 500 rpm. From the microscopic images of the machined surface, presence graphite powder in electrolyte has improved the machined features due to its conductive nature.