Daimler Chrysler Ag

Ulrich Haag

Uwe Hardtke

Thomas Huelsberg

Thomas Hulsberg

A process for manufacturing holes on the circumference of a hollow section situated in an internal high pressure forming tool uses the action of a punch integrated in the forming tool. A desired breaking point is formed on the hollow section, which follows the edge contour of the operating face of the punch; and after the withdrawal of the punch, the hollow section material surrounded by the desired breaking area, acted upon by internal high pressure, is extracted from the hollow section from the inside to the outside, forming a hole. In order to produce holes on the circumference of hollow sections, in which the shape of the outer circumference of the hollow section is maintained, the wall of the hollow section is weakened to form an unstable thin area. The punch penetrates into the wall of the hollow section at an internal high pressure which corresponds to the forming pressure for forming a hollow blank inserted in the forming tool. When the punch is withdrawn, the internal high pressure, tears the hollow section material surrounded by the thin area out of the hollow section in the withdrawal direction of the punch.

Process and device for manufacturing holes on the circumference of hollow sections

A method and a device for producing holes in the circumference of a hollow shape, with a wall piece being separated as a slug from the hollow shape in an internal high-pressure mold and being jammed without projecting relative to the outer circumference of the hollow shape in a previously produced hole. In order to remove the slug produced during punching in simple fashion from the internal high-pressure mold, the separated slug is jammed at a fluid pressure that is reduced relative to an internal high fluid pressure without loss via a punch and can separate the slug following removal of the finished hollow shape from the internal high-pressure mold, from the hollow shape, finally clearing the hole.

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Buxtehude, Germany

Ulrich Haag