Rubber pad forming
Rubber pad forming (RPF) is a metalworking process where sheet metal is pressed between a die and a rubber block, made of polyurethane. Under pressure, the rubber and sheet metal are driven into the die and conform to its shape, forming the part. The rubber pads can have a general purpose shape, like a membrane. Alternatively, they can be machined in the shape of die or punch.
Rubber pad forming has been used in production lines for many years. Up to 60% of all sheet metal parts in the aerospace industry are fabricated using this process. The most relevant applications are indeed in the aerospace field. It is frequently used in prototyping shops and for the production of kitchenware.
Rubber pad forming can be accomplished in many different ways, and as technology has advanced, so have the applications for this simple process. In general, an elastic upper die, usually made of rubber, is connected to a hydraulic press. A rigid lower die, often called a form block, provides the mold for the sheeted metal to be formed to. Because the upper (male) die can be used with separate lower (female) dies, the process is relatively cheap and flexible. The worked metal is not worn as quickly as in more conventional processes such as deep drawing, however, rubber pads exert less pressure in the same circumstances as non-elastic parts, which may lead to less definition in forming, and rubber pads wear more quickly than steel parts.
The Guerin process
The Guerin process, also called Guerin Stamping, is a manufacturing process used in the shaping of sheet metals. It is the oldest and most basic of the production rubber-pad forming processes.