Early Detection of Rejects in Presses

Various production parameters such as inhomogeneous material properties or varying lubrication lead to deviations in manufacturing. Quality management must ensure that the required geometric dimensions and tolerances are maintained. In many cases, the inspection is carried out randomly, manually and at the end of the production chain, which prevents early detection of rejects and intervention. The problem complexifies due to the increasing demand for 100% testing of workpieces, e.g. for safety-relevant components in the automotive industry. This leads to additional effort regarding time, personnel and logistics. One solution to these problems is the inline measurement of the workpiece geometry. Due to rough environmental conditions in forming machines, the implementation presents particular challenges. In this publication, the disturbance variables occurring in presses are described and requirements are derived which result for the applied sensor technology. Based on this, a methodology for measuring small rotationally symmetrical workpieces is presented.