Diagnosis of sheet metal stamping processes based on thermal energy distribution

Computer-aid design (CAD) and finite element analysis (FEA) have been widely used in sheet metal stamping nowadays, especially in automotive and aerospace industries. However, die tryout and fault diagnosis still heavily rely on the experiences of the machinists on the shop floor. In this paper, a novel approach is proposed using the thermal energy distribution of the part. The new approach is based on the fact that during the stamping process, the part absorbs energy to deform. Since most of the (plastic) deformation energy would convert to heat energy, it is therefore possible to detect possible defects by means of analyzing its thermal energy distribution. In practice, the thermal energy distribution can be acquired using an infrared camera. Furthermore, it is possible to compute the thermal energy distribution through a simple FEA. A practical example of cup drawing is discussed in details together with the experiment validation.