Method to form aperture in laminated trim sections for motor vehicles uses stepped punch to make small opening in laminate layer under tensile stress and then increase opening

摘要

The trim (1) consists of a layer (3) under tensile stress and a layer (2) subject to no or only small stress. An opening (10) is made in the first layer, which is smaller than the intended aperture (11), and reduces or eliminates the tensile stress in this area. The final aperture is then made around the opening. Both opening and aperture are made by punching in a single working stage, using a stepped punching die (5). This has first and second working surfaces (6,7), each with a ring-shaped blade-like outer edge (8,9).