Based on geometry model of single abrasive particle, comparing abrasive geometries of different materials displayed in SEM images, it is proposed that abrasive geometry is similar to inverted cone with vertex radius in sphere. Based on abrasives with inverted cone geometry, through introducing sliding ratio, mathematical models of cutting force and specific grinding energy of single abrasive have been established to study about cutting force in meshing line of single abrasive; in accordance with specific grinding energy of single abrasive, combined with internal meshing principle, the relationship among specific grinding energy, engagement, and meshing line length l have been studied. Through simulation analysis, it is shown that the unit normal force of single abrasive in whole meshing line gradually increases from tooth top to pitch line and tooth root; the greater the value of l from pitch line to tooth top, the more the specific grinding energy accordingly; however the greater the value of l from pitch line to tooth root, the smaller the specific grinding energy therewith; the greater the engagement, the smaller the specific grinding energy which tends to stable with changing of l.

Comparing with conventional WEDM in emulsion, dry finishing of high-speed WEDM (HS-WEDM) has advantages such as higher material removal rate, better surface roughness and straightness. Authors have presented a new procedure as gas-liquid combined multiple cut, in which roughing is processed in dielectric liquid, and semi-finishing is in liquid or gas, while finishing is in gas. For better understanding the effect of machining parameters on surface roughness and cutting speed in dry finishing, a L25(56) Design was implemented. The analysis of variance shows that the effect of pulse duration on surface roughness is of high significance, and peak current is of significance respectively, and the effect of no load worktable feed on cutting speed is high significant.