Sampling of IGES trimmed surface for an online inspection system

A CAD-directed online inspection system which can meet inspection tasks and integration requirements of a manufacturing system for parts that need to be redesigned according to their multivariate constraints is proposed. The IGES file generated from CAD/CAM platform is adopted as the carrier of CAD model information, and the format of IGES surface model is demonstrated. A method that combines uniform sampling and inserting sample points according to curvature variation is introduced to improve the efficiency and accuracy for the extraction of sample points. Then 3D surface is parameterised with parameters in 2D space, and sample points and edges are mapped to the same parameter space. In this way, points in trimmed area are identified and eliminated by judging of points in polygonal region or not. The simulation shows that the number and position of sample points can express the surface well and points in trimmed area are all identified, which makes a good preparation for the online inspection.