Force-based inline detection of wear evolution during blanking of cold rolled steels

Abstract

Blanking plays a crucial role in the metalworking industry as this forming operation defines the final geometric and functional properties of the product. However, the occurrence of wear, as a process-related uncertainty, has a significant impact on the product properties, so it is necessary to determine the occurrence and evolution of wear inline. As current methods are mainly limited to empirical wear monitoring and do not allow differentiation between the type of wear and its location on the tool, a method for monitoring wear based on the blanking force is established. To this end, an optical system is first constructed to observe the evolution of wear during the blanking process and to understand its occurrence. Four main types of wear are found in the processing of cold-rolled steels: adhesion and abrasion on the lateral surfaces, rounding of the cutting edge and chipping at the reversal point. To quantify the wear inline during blanking, features are extracted from the process force and correlated with the occurrence of each type of wear. Since high correlation coefficients are found between process force-based features and the form, size and localization of wear, the proposed method is suitable for inline monitoring of wear evolution in real blanking processes.