Forming tool for thin metal or plastic sheet parts, in particular automotive body parts, has a forming gap to which compressed gas can be fed and a pressure switch linked to a warning circuit

摘要

The tool die (4) or punch (1) has a bore (6) which enters the forming gap at a concave area of the tool surface. Immediately after tool closure a valve (10) is actuated to allow a brief connection with a compressed gas source (8). Back pressure in the bore is determined by a sensor (12) connected to a warning system (16,17) or computer (18) indicating a pressure trend which warns of excess material thinning.