The grey forecasting method is suitably applied to establish the predicting formula and acts as an auxiliary to calculate the unfinished experimental data. In this paper, a residual modified grey dynamic model RGM(1,3), using a technique that combine
residual modification with the rolling modeling, is proposed for fitting and predicting the surface roughness of SK3-YK30 tool steel in the wire electric discharge machining (WEDM). A statistical analysis of variance (ANOVA) is performed to indicate that the arc on time (AN) and the arc off time (AFF) of discharging are regarded as the significant processing parameters on the performance characteristics of surface roughness. The grey forecasting model of surface roughness is made up of the arc on time (AN) and the arc off time (AFF) of discharging by using the residual modified grey dynamic model RGM(1,3). According to the experimental results, the proposed model in this paper has high accuracy for predicting the performance characteristics and may also solve problems that have too few experimental data..
