A high-precision 3D model is created from the coin design, which is then milled into the master die. Creating an image on a special coin involves three stages:
The coin design is transferred to a digital 3D model. Based on this, an oversized synthetic model is produced using a CNC milling machine. This model is used to check all the details.
The design can now be reduced to coin size and milled into an unhardened steel cylinder. This is a laborious process as all the details of the model have to be transferred. It takes between 8 and 14 hours. The resulting die is called the master die.
The master die is hardened and the actual embossing dies are now produced in the negative by repeated sinking. Up to 5000 special coins can be minted with one pair of dies.