Coining is the squeezing of metal while it is confined in a closed set of dies.
A workpiece is placed a confined die. A movable punch is located within the die. The action of this punch cold works the material and can form intricate features.
This process is used to produce coins, medallions and other similar products on flat stock with relief features. Very fine detail can be reproduced. Pressures as high as 1375 MPa (200,000 psi) is required to generate very fine features.