Method of and apparatus for the cutting of an opening in a hollow body

摘要

In the internal pressure shaping of a tubular workpiece into a hollow body in a surrounding die, an opening can be formed in a wall of the workpiece by advancing a plunger while the maximum internal pressure is maintained to partially cutout a piece of the wall corresponding in shape to the plunger. That piece remains attached by a portion of the thickness of the wall. Their upon the internal pressure is reduced and the plunger is retracted until the cutout portion is pressed fully from the workpiece.