Coining is a form of precision metal stamping in which a piece of metal is subjected to an enormous amount of stress in order to induce plastic flow on the surface of the material. One of the beneficial features is that in some metals, the plastic flow reduces the metal’s surface grain size, which then work hardens the surface of the metal, while the deeper material of the part retains its toughness and ductility. The term “coining” comes from the initial use of the process which was in the manufacture of coins.

Coining is also used to manufacture small parts, such as washers, for many industries and is commonly used when very fine features and a high relief are required. As an example, not only is it used to produce coins, but also to produce medals, badges, and buttons, as well as precision energy springs and precision parts with small or polished surface features.

Coining typically requires a much higher tonnage for it’s presses than stamping, because the workpiece is plastically deformed and not actually cut, as in some other forms of precision metal stamping.

Metal bending is a manufacturing process in which a V-shape, U-shape, or channel shape is produced along a straight axis in ductile materials, most commonly sheet metal. Commonly used equipment includes box and pan brakes, brake presses, and other specialized machine presses. Some typical products that are made using this method are boxes such as electrical enclosures and rectangular ductwork.

When using press brake forming, the work piece is positioned over the die block and the die block then presses the sheet to form the proper shape. Usually, bending has to overcome not only tensile stresses but also compressive stresses as well. When metal is bent, the residual stresses often cause the material to spring back towards its original position, so the sheet has to be bent further than needed to achieve the proper bend angle. The amount of spring back is dependent on the type of material used as well as the type of forming. When sheet metal is bent, it also stretches in length. The bend deduction is the amount that the sheet metal will stretch when it is bent as measured from the outside edges of the bend. The bend radius refers to the inside radius of the bend. The formed bend radius is dependent upon the dies used, the properties of the metal, and the metal thickness. For example, the U-punch forms a U-shape with a single punc