ABSTRACT
Although mechanical forces are of increasing interest, air pressure is still widely used to accomplish the forming task. It is a gentle force, leaves no marks on the surface, acts in all directions with equal force, and is readily available. The magnitude of this force is established by the difference in the air pressure acting on each side of the sheet. With a vacuum on one side, the maximum pressure available is the atmospheric pressure of 14.7 psia. For most forming processes only a fraction of this pressure is attained. If higher forces are required or if it becomes impossible to establish a good seal at the low-pressure side of the sheet, pressurized air can be used. Other advantages of using pressurized air are described later.
