A geometric method for assembly tolerance analysis based on CAD system

To solve the analysis of complex tolerance problem efficiently, a new geometric method is discussed based on products´ digital models and parameter driven technique of CAD system. Firstly, tolerances were translated into geometric character, and then accessioned to products´ digital models. Secondly, establish size constraint solver, by utilizing the ability of CAD system to disposal geometry element, the digital models are remodeled. Finally, the complete loop is measured. Then we know the precision of assembly. These methods are implemented on the UG system, and applied to analyze the assembly of a selected mechanism. The preliminary application shows that the new geometric method can afford results with high precision efficiently.