Influence of different tool polarity on short electric arc machining of GH4169

Abstract

Short electric arc machining is a recently developed high-efficiency electrical discharge machining technology. Material removal rate, tool mass wear ratio (θ), and workpiece surface roughness (Ra) are important indexes used to evaluate the machining performance of short electric arc machining. In order to obtain better machining effect, the nickel-based superalloy GH4169 is machined by graphite in this article. The influence of voltage, duty cycle, and flushing pressure on short electric arc machining performance is then investigated under different tool polarity conditions. Experimental results show that higher material removal rate and lower θ can be obtained by negative polarity machining, while positive polarity machining can produce better surface quality. To investigate the cause of this difference, the surface integrity of GH4169 machined by different tool polarity is studied from macro and micro perspectives.