Upsetter Upset forging, sometimes called Heading, is performed on a horizontal forging machine called an Upsetter. It is essentially a process for enlarging and reshaping certain sections of a bar or tube. In its simplest form, hot upset forging is accomplished by holding the heated stock between two half dies and applying pressure to the end of the stock in the direction of its axis with a heading tool, which upsets (spreads) the end by metal displacement. Present day machines and tooling permit the use of multiple pass tooling that can produce complex shapes accurately and economically. The process is now widely used for producing shaft type parts, ranging in complexity from simple headed bolts to flanged shafts, cluster gears, and wrench sockets that require simultaneous upsetting and piercing. Forgings requiring center (not at the bar end) or offset deformation may also be produced. Hot upsetting may be used to preform or prepare sock for another forging machine, such as a hammer or press, or as a finishing operation following forging such as upsetting a flange on the end of a crankshaft. In addition to upsetting, the heading tools are used for piercing, trimming, extrusion, and bending. In the upset forging process, the working stock is confined in the die cavities and the heading action creates the pressure required to fill all of the die impressions completely. Since the dies are split, a wide variety of shapes can be forged and easily removed from the tooling, which is primarily composed of three die elements – two gripper and cavity dies (one is stationary and one is fastened to the moving die slide), and the punch, which is fastened to the header slide (ram). During the upset forging cycle the movable die slides to the stationary die to grip the stock. The punch that is fastened to the header (ram) advances forward and forces the stock into the cavities of the dies. When the punch retracts about 60% of its full stroke. The movable die slides to its open position allowing the forging to be released. The forging may then be shifted down to the next pass (die) where the cycle may be repeated. Many forgings require multiple passes (some as many as six) before completion. The stock may also be forged on one end and then slipped over (reversed) to be forged on the other end in one heat-cycle. After completion of the forging operation, the forgings are usually dropped through the throat of the machine to a conveyor that delivers the hot forgings into a metal tote box for cooling and transportation.