An Approach to Feature-Based Inspection Planning

Summary

An automated, feature-based CNC CMM inspection task planner has been developed for 3D solid CAD models. The part was modeled using the CSG representation in the solid modeller CATIA ver 3 rel 1. Both the geometric data and tolerances of the part were first extracted then classified. A PC-based inspection task planning module, written in C, ranks this information so that inspection codes for the CNC CMM can be ultimately generated. A CAD-CMM interface was used to pre-process the APT-like inspection plan into a neutral data format which can then be post-processed into the CNC CMM’s machine code. This post-processed inspection data file was then downloaded from the CADCAM System to the PC linked to the CNC CMM. The inspection path, showing the probing points, may be previewed on-screen before execution. Basic engineering shapes such as cones, cuboids, cylinders and inclined planes can be inspected. The results of inspection trials carried out on two test blocks with these geometric features are presented.