Stamping processes are primarily used to produce flat parts of various materials (sheet, cardboard, textiles, etc.) with a press and a cutting die.
The upper part of the die (the stamp) has the interior shape; its lower part (the die plate) has the corresponding opening, i.e., the exterior shape, which might take the form of holes, for example. Several processes (such as bending operations) are integrated into special progressive dies used during high production stamping.
High production stamping is a special form of stamping designed to maximize the number of parts. This focuses on the small, but highly precise, parts. Metallic materials, such as brass, stainless steel, bronze or copper beryllium, sometimes precious metal coated, and also other materials are processed, for example pure precious metals or plastics.
The high performance stamping process works directly from a coil (wound metal strip). During this process, the strip is guided through precision presses with a nominal pressing force between 250 and 4000 kilonewtons at a rate of 400 to 1400 strokes per minute. To guarantee high precision, the vibrations which occur during the stamping process must dissipate quickly, which is why these high production presses must have a high rigidity. In addition, the press must resist tilting.
During production, the stamping die plays a critical role (stamping/bending or progressive dies) since it is exposed to extremely high stresses and also must maintain high precision through a long period of use. The stamping die is generally made of carbide using grinding or electrical discharge machining methods. The dies must be used efficiently and protected effectively during operation. A frequent limitation to the stamping process is that the “punched pieces” rise up and are carried along. These are normally small pieces of residue resulting from the stamping process. They can damage both the die and the product and also can lead to delays in production. Spring-loaded casting pins in the punch, a special polish of the punch face, and force or ultrasonic sensors in the die are used to avoid or to reduce these problems.
The design and construction of a stamping die require technical expertise and years of experience. Both are available at Heraeus with an in-house design department and in-house tool making. This puts Heraeus in a position to produce highly complex, custom made dies for our customers in our own facilities.
