Parametric investigation of the effect from controlling variables on thermal deformation during stamping process in automotive body part

The purpose of this study is to analyze the thermal deformations that degrade the quality of assembled products through the stamping process. Special attention was paid to the ambient temperature change in the manufacturing process of automotive body part. First, we found that ambient temperature, which is the external condition and difficult to control, can be varied significantly due to seasonal change thus it can be an important factor for the deviation from thermal deformation. Important controlling factors for thermal deformation were identified and their effects on final dimensional changes were carefully analyzed by the design of experiments (DOE) procedure. Based on DOE result, we found that the influence of each controlling factor was non-uniform across the target surface. To understand the local variation clearly, vectorized plot of the thermal deformation was introduced for visualization. Locations vulnerable to thermal deformation have been identified and it was confirmed that ambient temperature change has significant effect especially on those weak spots. Finally, we tried to reduce the deviation from thermal deformation by controlling the initial temperature of the mold and the blank. We found that controlling the initial blank temperature was more effective.