Machining Performances of Electrical Discharge Machining Combined with Abrasive Jet Machining

The aim of this study is to investigate the machining characteristics of a developed hybrid process of electrical discharge machining (EDM) in gas with abrasive jet machining (AJM). The experiments with regard to parameter optimization were designed with an L18 orthogonal array based on Taguchi method. The main process parameters such as machining polarity, peak current, pulse duration, gas pressure, grain size, and servo reference voltage were chosen to determine their effects on machining performance relating to material removal rate (MRR), electrode wear rate (EWR) and surface roughness (SR) for SKD 61 tool steel. The experimental response values were transferred to signal-to-noise (S/N) ratios, and then the significant machining parameters associated with the machining performance were examined by analysis of variance (ANOVA). The optimal combination levels of the machining parameters were also obtained from the response plots of S/N ratios. The experimental results show that the significant machining parameters affecting the MRR were machining polarity, peak current, and pulse duration; peak current was the significant parameter with relation to the EWR; in addition, the peak current, pulse duration, as well as gas pressure were the significant in regard to the SR. Moreover, The S/N ratios were improved 9.51 dB, 3.44 dB and 4.52 dB at the optimal combination levels of machining parameters from the confirmation experiments for MRR, EWR and SR, respectively. Consequently, the developed hybrid process of EDM in gas and AJM could enhance the machining efficiency to fit the requirements of modern manufacturing applications.