Clearance Verification between Stamping Dies by Using Virtual Die Machining Method

Abstract

In the press-working of sheet metal parts for automobile bodies, two stamping die CAD models with mutually inverted curved surfaces are necessary. They are designed to have some clearance between them when they are assembled so that they can properly hold a sheet metal within. Since these two models have very similar curved surfaces, engineers usually design a single CAD model only. The other model is obtained by copying, partly modifying, and inverting the designed model. The modification is generally very small and limited, and the visual inspection of the modified shape is difficult. False modifications often cause bad results in the later trial press-working process and expensive design reworks become necessary. In order to assist the stamping die designer, the authors developed an algorithm for visually inspecting the clearance between the designed model and virtually machined model of its modified counterpart. A fast clearance inspection between 2 models is achieved by using the hierarchical structure of OBBs and the multiple-threading technology.