Evaluating the Reliability of a Nondestructive Evaluation (NDE) Tool to Measure the Incoming Sheet Mechanical Properties

Today, the automotive OEMs and part suppliers are increasing their material suppliers globally. Therefore, the same grade steels are supplied by different steel mills and batch conditions to meet this requirement. However, the variation of the incoming mechanical properties can significantly influence the stamping quality associated with necking, wrinkling, and cracking. This increases the overall manufacturing costs and lowers productivity. Nondestructive evaluation (NDE) tools have become useful to reduce this uncertainty by measuring incoming mechanical properties. The measured data can be used during production in a feed-forward control to select the optimal process parameters or as forming process parameter optimization using simulations. A detailed evaluation of a 3MA (micromagnetic, multiparametric microstructure, and stress analysis) Fraunhofer IZFP’s device and its viability of implementations in a production environment is introduced. The 3MA equipment was incorporated into an industrial flexible robot and a practical calibration procedure was developed and validated for Bake-Hardening (BH) 340 steel.