Coining (metalworking)

Coining is a form of precision stamping in which a workpiece is subjected to a sufficiently high stress to induce plastic flow on the surface of the material.

Coining is used to manufacture parts for all industries and is commonly used when high relief or very fine features are required.

For example, it is used to produce coins, badges, buttons, precision-energy springs and precision parts with small or polished surface features.

Coining is a cold working process similar in other respects to forging, which takes place at elevated temperature; it uses a great deal of force to elastically deform a workpiece, so that it conforms to a die.

In soldering of electronic components, bumps are formed on bonding pads to enhance adhesion, which are further flattened by the coining process.