Design guidelines for embossing
General design guidelines for hollow embossing can be derived from experimental and theoretical investigations. These guidelines can be used as early as the design phase to detect and prevent premature coinage failure.14
Material:
The material plays a crucial role in the stretch forming capability of the embossing. For a given tool geometry, the embossing height can be increased with a material that has a higher hardening exponent.
Lubrication:
The embossing height can only be influenced minimally with lubrication. The drawable floor height of a conical floor shape can only be increased by 6.7% by applying lubricant to both sides.
rolling direction:
The position of the embossing in relation to the rolling direction of the sheet is of secondary importance.
tool geometry:
The maximum drawable embossing height h is the most important parameter. It depends crucially on the following tool parameters:
- punch diameter d
- Punch corner radius rSt
- Die radius rM
- Draw width w or flank angle α
These guidelines are designed to ensure that embossing can be performed successfully and efficiently.