Stretch Forming

The blank is firmly clamped at much or its entire circumference and the shape is developed by the penetration of a punch, at the expense of sheet thickness. Small quantities can be generated with only a punch, even though at higher material cost, as in the aircraft industry.

Mating dies with carefully designed blank holders are more economical for the large quantities; typical of the automative and appliance industries. An important aspect of the process is the control of or compensation for elastic recovery (spring back), which distorts the shape. Embossing is a highly localized form of stretch forming.