Power Press

Power presses that shear, punch, form, or assemble metal or other material using tools or dies attached to slides. Power presses can be mechanical, hydraulic, or pneumatic. In mechanical power presses, tools and dies are mounted on a slide or ram and move away from the stationary bed containing the lower die. The upper and lower dies press together to punch, shear, or form the workpiece.

Improper use of mechanical power presses cause a large number of workplace amputations. Crush injuries and fractures to the fingers, hands and arms are also common injuries.

The two types of power presses are:

• full revolution (positive clutch) – once activated, it cannot be stopped until the press cycle is completed by lowering and raising of the slide or ram. Presence sensing devices will not work on these machines. Operators must be protected by fixed guards or mechanical interlock guards during the entire operating cycle.
• part revolution or friction clutch – can be disengaged at any time before it completes the down stroke. Can be guarded with presence-sensing devices.