Process for fabricating large-surface metal plate into a shaped part, such as an outer skin panel of a vehicle body

A process for forming a large-surface metal plate into a shaped part having a central section and a boundary section, the process comprising the steps of:

• forming the central section by external high pressure punching;
• and
• forming the boundary section by pressing with a greater degree of deformation compared to a degree of deformation of the central section, using a molding tool having a reservoir filled with incompressible fluid work medium and having profiling elements, arranged therein for the boundary section of metal plate clamping jaws for tight clamping of the metal plate in an outside boundary section at the edge of the reservoir and a shaping die, movable towards the reservoir and having at an outer edge configured profiling elements corresponding to the profiling elements of the reservoir,
• wherein the external high pressure punching by the shaping die moving forward against the pressure of the fluid work medium is ended, when the shaping die reaches the profiling elements in the reservoir, by the pressure of the fluid work medium in the reservoir being reduced, and
• wherein the boundary section of the metal plate is formed between the profiling elements of the shaping die and the reservoir pressing against each other at a pressure of the fluid work medium that is lower relative to the pressure of the fluid work medium when the central section is formed, or at zero pressure.