Preparing a wax model
The first step in the production of a new coin is the artist's sketch. From this, the artist creates a wax model, converting the flat sketch to a relief.
Then a silicon rubber model is made, which in turn is the basis for the sometimes numerous plaster moulds. Finally, a mould of hard plastic is cast. The models are around seven times larger than the minted coin. It is difficult to make models since a good large-scale model does not necessarily mean that the actual coin – on which all details will be very small – will be a success. Often various draft models must be made before the final design of the coin is found.
The hard plastic model is then reduced to the actual dimensions of the coin. This is a very lengthy process. For instance, it takes 20-24 hours to reduce a 5-krone coin. Reduction takes place in a reducing machine where a sensor registers "peaks" and "valleys" on the model.
A small-scale miller then transfers the "pattern" to a steel piston called an original die.
The final minting dies are created from the original die. In contrast to the flat original die the minting dies are convex, i.e. they are higher in the centre than at the rim. When a convex die is used to stamp the coins the die first hits the centre of the metal disc (the blank) on which the coin is stamped. Then the metal "flows" outwards like a wave as the piston is pushed down onto the blank. The result is a clearly embossed coin. If flat dies were used instead, the metal would not flow outwards and the embossment would not be visible.
The Royal Danish Mint's minting machines can mint around 700 coins per minute.