Influence of porous structure on the machining performance of micro EDM

Porous metals are widely used in acoustic or heat absorbing material, heat exchanger, catalysis and biochemical products. Porous metals are available to be processed by electrical discharge machining (EDM). However, the relationship between machining parameters and performance is unclear. In this investigation, extensive experiments are conducted on solid stainless steel 304 and porous stainless steel 304 with different pore sizes. Material removal rate (MRR) and tool wear ratio (TWR) are used to evaluate the machining performance of micro EDM. It was found that the machining of porous metal has a higher MRR and lower TWR than those of solid one. It was also found that the machining performance is significantly affected when the size of porous metal is close to the discharge gap. The abilities of debris removal and machining in porous metal machining by EDM are proposed to analyze this phenomenon. Experimental results match the calculated values well. It is helpful to select proper machining parameters of micro EDM to process porous metals.