**2. Die face**

The die face plays a crucial role in drawing operations as it determines operation quality (Makinouchi, 1996). Not only does the design have to prevent sheet metal from cracking, wrinkling, offset of the characteristic line, it also has to take the following factors into consideration including compensation of springback, and whether the trimming mold should use normal cams or suspended cams, whether the restriking mold should use a convex hull, and piercing direction. Designers usually search for previous successful cases as references when designing a new die face. This design process is explained in Section 2.2.
