Medical precision metal stamping

Metal stamping process: the elements of designing parts

Precision metal stamping is an economical process that can produce a large number of precision parts from sheet metal or strip metal with high productivity, usually using special tools. The precision stamping industry produces components and components involved in our daily lives, from electronic products to transportation. Your phone has tiny stamped metal contact pins that can send power and signals throughout the phone. The structural elements of the car you drove to work this morning are made of precision metal stampings and components.

The essence of the metal stamping process includes punching flat, sharp-edged tool steel into a matching die cavity to punch, trim and punch the material. This process can be used to produce perforations, trim edges and finished sheet metal parts of various shapes and sizes.

When designing metal stamping parts, the metal always maintains a consistent wall thickness. As we all know, any feature contained in a part will have the same wall thickness. What happens when we punch holes on it? What should I expect when creating trim edges?

Product parameter

Anatomy of the hole

The cutting gap between the punch and the die is strictly defined and specified, and the process produces very predictable edge conditions on the finished part. Basically, the punch first attempts to compress the material, creating a curled or rounded top edge. When the sharp punch starts to cut in, it cuts the material, creating a straight, polished wall, usually 1/4 to 1/3 the thickness of the material. As the force accumulates beyond the strength of the material, it yields and breaks away at the same angle as the punch and die cutting gap, resulting in burrs on the bottom edge.

Glitch

Burrs, such as parting lines in plastics or burrs on castings, are normal by-products of the metal stamping process. Blanking burrs are usually a bit jagged and sharp. As the punch and die edges become dull, their height may vary, but it is generally expected to be up to 10% of the material thickness. When needed, a large number of finishing processes or secondary processing can be used to passivate or remove burrs, depending on the application.

Hole size and tolerance

Since the punch and die gap is usually about 8% to 10% of the material thickness on each side, the bottom of the hole or trim will gradually reduce the die gap. Therefore, the internal dimensions are usually measured at the shear or the smallest part, regardless of fracture. If this detachment cannot be tolerated in a particular application, the geometry should be specified, and non-standard methods can be used. For most applications, normal piercing and blanking operations have extremely high repeatability, and very small tolerances can be achieved.

By using dedicated, customized tools and appropriately sized stamping equipment, a large number of precision parts can be produced during the entire life cycle of the product's operation. In most cases, as the product is revised and improved, tool changes can be made easily and economically to adapt to the changes.