Some Investigations on Punch Force in Cold Forging Process by FE Simulation

There are several factors affecting the estimation of the punch force in backward extrusion process of the cylindrical cup. In the present investigation, the focus is on the billet size, reduction ratio, face flow angle of the punch and land height. The billet material is AISI 1010 steel and the diameter of the billet is constrained to 30 mm for technical implications considering tooling and available press specifications. The height of the billet is altered only for varying initial height to diameter ratios. The effect of selected factors on the estimation of punch force is presented through well planned finite element (FE) simulations. The FE simulations were carried-out based on four factors at four levels full factorial design (FFD) using response surface methodology (RSM) model. The fitness of the developed model to predict the punch force was checked through analysis of variance (ANOVA). The FE simulation results were validated with shop floor experiments. The investigations revealed that the punch force tends to decrease with increase in reduction ratio; whereas the force increases with punch face flow angle and land height. On the other hand, there is a marginal increase in the punch force with increased billet height is evidenced.