Abstract
One problem in the blanking of a motor core has been that products tend to become oval shaped. In this research, a method of expressing dimensional changes was investigated using the distributions of stress and strain in a deformed material by finite element method (FEM), to manufacture products of high circularity by circular blanking. The effects of the clearance between the punch and the die, and the material anisotropy property, namely, r, on the dimensional change of the blank were examined. In addition, the validity of the method was confirmed by comparing the calculated and experimental values. The result showed that the configuration factors of the process of the dimensional change included the timing of fracture, the position of fracture, and the extent of plastic elongation, and that the process was affected markedly by clearance and r. The extent of plastic elongation decreased when clearance increased; it increased with decreasing r, because the extent of plastic deformation increased, therefore taking time to the start of fracture. The analysis results showed good correlation to the experimental ones. It is suggested that the method can be used to predict dimensional changes of products.
