Modeling and numerical analysis of the process of punching aluminum sheets taking into account punch wear

The paper presents a modeling and analysis algorithm as well as the results of simulation tests with the use of FEM of a process of punching aluminum sheets used for casings. In industrial practice, the difficulty lies in the correct selection of punching clearance. In order to predict the effect of clearance on the quality of the edge cut, a numerical model was developed taking into account the geometric and physical nonlinearity with damage. The model makes it possible to simulate all the phases of the cutting process, including the fracture phase, which is of key importance to the formation of the workpiece edge. A new approach of creating a real geometry of the punch edge was presented. The geometries developed take into account the most common defects of the punch cut edges. Owing to this, it is possible to predict the course of the proces depending on the type and degree of the wear of the cutting edges of the punch. The results obtained showed that for clearances below the value of a = 0.16 mm, the crack has the shape of a straight line. Clearance values a = 0.16 mm and below allow one to obtain a perpendicular shear area and a considerable width of the smooth cutting zone. As the clearance increases, the width of the cutting zone decreases. Punch wear significantly reduces the smooth zone and it increases perpendicular deviation of cut surface.