Types A schematic of coining with a backgauge The U-punch forms a U-shape with a single punch. The formed bend radius is dependent upon the dies used, the material properties, and the material thickness. The bend radius refers to the inside radius. The bend deduction is the amount the sheet metal will stretch when bent as measured from the outside edges of the bend. When sheet metal is bent, it stretches in length. The amount of spring back is dependent on the material, and the type of forming. When bending is done, the residual stresses cause the material to spring back towards its original position, so the sheet must be over-bent to achieve the proper bend angle. Usually bending has to overcome both tensile stresses and compressive stresses. In press brake forming, a work piece is positioned over the die block and the die block presses the sheet to form a shape. Typical products that are made like this are boxes such as electrical enclosures and rectangular ductwork. Commonly used equipment include box and pan brakes, brake presses, and other specialized machine presses. Bending A chimney starter, a sample product of bendingīending is a manufacturing process that produces a V-shape, U-shape, or channel shape along a straight axis in ductile materials, most commonly sheet metal. For the form of stage magic, see Spoon bending.
