Formula of average value: after designing the carrier tape under CAD, calculate the area s at the top of the carrier tape.

The product of S and leather thickness t is the overall product V of leather blanking, and then calculate the surface area s’ of each surface of the cavity, then V / s’ is the required average thickness t. 

The dimensions of A0 and B0 are relatively accurate, and the thickness of the bottom will be a little smaller. But this formula is not omnipotent. Individual cavities will be larger when calculated!  just for reference!