Excenter pressing (piston and die pressing, eccentric pressing) is a certain kind of pressing performed in a press that uses an excentric mechanism to do the punches.
The excenter press uses a mechanism called excentricity to transform the rotational force from its engine to a linear reciprocal force, which in this case is used to perform punches. There are excenter presses that do one punch (single stroke presses) or multiple strokes on every component.
See "Presswork" for more information.