Stamping is a process in which thin walled metal parts are shaped by punches and dies. The punches and dies are mounted on mechanical or hydraulic presses and they perform two functions during the stamping process: shearing and bending. Mechanical presses utilize a flywheel to store the energy required for the stamping operation. The flywheel runs continuously and is engaged by a clutch only when a press stroke is needed. The drawback of mechanical presses is the driving force varies with the length of the stroke. Hydraulic presses use pressurized oil acting against one or more pistons to drive the punch and die on the press. It is capable of providing full force of the hydraulically driven piston over the entire length of the stroke. However, hydraulic presses are slow compared to mechanical presses. Most stamping operations are carried out on high-speed mechanical presses even though they are more expensive than hydraulic presses.
Stamping operation can be done at either a single die station or multiple die stations using progressive dies. Progressive dies is often use when the part contains closely spaced features or if they have bend angle greater than 90°. They can also reduce die wear and decrease the amount of spring back (thus improves geometric accuracy). The disadvantage of progressive die is they require multiple stations, which requires more space to accommodate additional presses.
In order to minimize die cost, the following guideline should be followed while designing parts for stamping manufacturing process:
