Tool-integrated spring back measuring system for automotive press shops: A contribution to the quality control of complex car body parts

The spring back on car body parts defines their dimensional accuracy. Throughout the production process in press shops the conformity with the geometrical specification is inspected by tactile or optical measuring devices offside the production line in no particular order. To enable an efficient control of dimensional accuracy during production processes, this study deals with the investigation of a tool-integrated measuring system, which generates specific geometrical information for every produced part. On a pilot basis, eddy current sensors for distance measurement are integrated into the tool-support of an inner door panel. The system shows that it is able to detect process variations such as different material batches or variations in blank holder forces and their effect on the forming process, resulting in changes of the car body geometry.