Tolerance evaluation system of manufactured parts based on soft gaging

摘要

This report deals with soft gaging as an inspection technique for manufactured aprts.First,we propose a modeling of soft gagingh for inspection of tolerances on features with or without a relationship between the feature and the datum.The soft gaging model that conforms to the geometric tolerance standards is represented using ISO10303-11 EXPRESS-G notation.We also propose mathematical definitions of soft gages for such tolrances and the procedure fo the evaluation of such tolerances of machined parts based on a CMM measured point set in this paper.Second,we develop a tolerance evaluation system of machined parts based on the proposed soft gaging and a fitting procedure based on a small displacement screw method considering spatial constraints,which enables the fitting of the soft gage into a measured point set of the machined parts and thus deriving a deviation.Finally,we also show that the proposed method is very effective in its application to certain inspection examples.