Sensor Placement Strategy for Stamping Tooling Integration Based on...

Monitoring contact pressure distribution across the sheet metal-tool interface by means of tool-integrated sensors is a relatively new approach to stamping process monitoring. The first step toward realizing such a system is to determine the number and location of sensors to be integrated into the tool structure. This paper examines three mathematical methods [rectangular meshing on polygonal spaces by Schwarz-Christoffel mapping (SCM), low discrepancy sequences (LDS), and largest empty circles (LEC)] for process-independent selection of sensor locations on a tool with a given geometry. The comparative merits of these methods have been investigated based on a finite element model of a panel stamping process. Contact pressure data at the tool geometry was extracted from the finite element model at sensor locations generated by the three methods. This provides a numerical reference base for the pressure that would measured by sensors placed at those locations.

These spatially discrete pressure measurements were then used to interpolate the contact pressure distribution on the tool surface by means of thin plate splines. Comparison of the thin plate splines with the FEA-determined contact pressure solution provides a quantitative measure for comparing the performance of the three geometric sensor location methods. Results indicate that the LEC method provides for the most accurate regeneration of the contact pressure distribution. The results and methods presented are relevant for further experimental research and potential industrial applications. Published in the Transactions of NAMRI/SME, Vol. 37, 2009, pp. 605-612.