The original definition of forging is the "mechanical deformation of metal when heated to a plastic state". However, in recent years it has come to include similar operations done in the cold or room temperature state as well. However drop forging is also used for a number of appl0ications due to its peculiar traits.Drop forging is a metal shaping process in which a heated workpiece is formed by rapid closing of a punch and die forcing the workpiece to conform to a die cavity. A workpiece may be forged by a series of punch and die operations (or by several cavities in the same die) to gradually change its shape. Drop forging is also called impression die or closed die forging, or rot forging. Process characteristics- gradually forms heated metal by singular or repeated blows in a sequence of individual or multistage die cavities. Produces a parting line and flash on the workpiece; flash must be removed. Typically requires machining to obtain dimensional tolerances and good surface finish. Drop forging is a process used to shape metal into complex shapes by dropping heated metal into a punch and die which compresses to gradually change the shape of the metal. The process- the process of drop forming is very simple. The workpiece is placed into a die and punch, then the impact of a ram on the punch causes the heated material, which is very malleable, to conform to the shape of the punch and die cavities. Typically only one ram is needed to completely form the part. The extra space between the die and punch is called the flash. It acts as a relief valve for the extreme pressure produced by the closing of the die halves but is eventually trimmed off of the finished part.
Equipments- the equipment used in the drop forming process is commonly known as a power drop hammer. These may be powered by air, hydraulics, or mechanics. Depending on how the machine is powered, the mass of the ram, and the drop height, the striking force can be anywhere from 11,000 to 425,000 pounds. The tools used are dies and punches, come in many different shapes and sizes, as well as materials. Examples of these shapes are flat and v-shaped which are used for open-die forging, and single or multiple-impression dies used for closed die-forging. The designs for the dies have many aspects to them that must be considered. They all must be properly aligned, they must be designed so the metal and the flash will flow properly and fill all the grooves, and special considerations must be made for supporting webs and ribs and the parting line location. The materials must also be selected carefully.
