According to the friction analysis between punch and sheet during thin plate blanking,the calculating formula of friction force was derived and quantitative relationship between burnish band on the shearing surface of the sheet material and the wear on the punch flank was obtained.The grey prediction model of tool wear was established and its accuracy and efficiency were verified by high speed blanking experiment.

Based on the numerical simulation and torque equilibrium theory,an optimal method was applied to calculate the torque difference between both sides of the center line;and the offset distance was obtained.The data got from the method applied in a progressive die for an electronic shell part was compared with the calculating results from the conventional analytical method and it shows effective and accurate in optimizing the pressure center of progressive dies.