ABSTRACT
One of the most difficult issues encountered during the electrical discharge machining (EDM) of metal matrix composite (MMC) is the flushing of debris that remains after the test between the electrodes passage. The formation of electric arc and short circuiting also takes place when disintegrated particles build in the electrode space, reducing the material removal rate and surface integrity. In this work, a parametric study of the Electric Discharge Drilling (EDD) operation has been done using an air-assisted multi-hole slotted rotary tool during machining of Al-SiC composite. The employment of a multi-hole slotted tool results in the effective extraction of deteriorated particulates from the discharge gap, improving process performance. Effects of process parameters like discharge current, tool speed, discharge air pressure, pulse on time, and duty cycle have been studied by assessing them as input factors with process responses electrode wear ratio (EWR) and material removal rate (MRR). A comparison of responses with a solid rotary electrode and an air-assisted multi-hole slotted rotary electrode is introduced. Regression analysis and analysis of variance were used to evolve and determine the competency of the evolved MRR and EWR models. MRR is found to be higher, while EWR is found to be lower in the case of air-assisted rotary EDD (AAEDD) in comparison to conventional rotary EDD (REDD) processes. Formation of fewer recast layers and surface cracks in the AAEDD process in comparison to the REDD process has been found. The optimized MRR value of 25.30 mg/min and the EWR value of 1.35 were acquired with optimal input parameters by optimizing established statistical models with a genetic algorithm. The present work proposed a novel method for improving the machining performance by improving the flushing efficacy of the machining region resulting in a better material removal mechanism.
