Direct generation of die surfaces from measured data points based on springback compensation

Reverse engineering is an approach for constructing a CAD model from a physical part through dimensional measurement and surface model. For sheetmetal parts, when removed from dies after forming, are subject to springback due the resultant in-plane forces and moments throughout the sheet at the end of the forming processing. Therefore, springback should be compensated for integrating reverse engineering into the system of forming sheet metal with a complex surface. However, CAD modelling from measured points data is a roadblock to the automation of the duplication procedure. The difficulties here arise from surfaces fitting to measured points, which is well-known to be time-consuming. To avoid the roadblock, based on the convex hull property of B-spline, a new strategy for direct generation of die shapes from digitized points with springback compensation is presented in this paper. The proposed algorithm has been applied to a part of complicated geometry with good results.