An inspection information integration system of CAD and CMM

Manual definition of inspection feature in Coordinate Measuring Machines (CMM) is time-consuming and error-potential. Since CAD model contains all design data, an integration system of CAD/CMM is constructed to automate above process. First, tolerance feature and its attributes, including tolerance type, value and tag of related geometry, are extracted from CAD model and written to QDAS file, based on feature technology. The tags are then added as attribute to related geometry in CAD model. Thereby they can be automatically remarked in the parameter list of their corresponding geometric item when exporting STEP file. At last, both STEP and QDAS file are imported to CMM system. Based on the mapping between geometric and tolerance feature in neutral files, inspection features can be recognized by CMM without manual interruption. The system has been implemented on Unigraphics platform, and proved to applicable for all types of tolerance and geometry.