Closed-die forging, or impression-die forging, involves the metal being placed in a die that contains the shape of the part. The metal is then hammered or pressed, causing the metal to flow and fill the die cavities and the shape of the part. After forging, the flash is removed. With closed-die forging, little to no machining is needed. The process utilizes the force from the hammer or press and, often, heat in order to deform the metal to fill an enclosed die impression that contains the shape of the part.