Forging is a manufacturing process involving the shaping of metal using localized compressive forces. The blows are delivered with a hammer (often a power hammer) or a die.

Forging hammers are used in the drop forging to form the metal between two dies. The first half of the die is attached to the anvil and the second part to the hammer. The material is placed in the lower die and then hammered with the upper one until the hot metal flows in all directions, filling the die cavity. Drop forging is the first industrial process which had been developed for closed die forging, before the introduction of presses.