Tolerance Modeling Using the Feature Based Product Model for Prediction of Used Parts Deterioration

The objective of this paper is the prediction for the deteriorated status of mechanical parts based on the feature-oriented product model for supporting the parts reuse phase. As the first step, the product model with “Geometrical Quality Feature” is proposed for representing the deteriorated status. The geometrical quality feature consists of “form tolerance” and “geometrical-relation constraint”. Based on the TTRS (Technologically and Topologically Related Surface) method, the form tolerance is described for representing deteriorated deformation of each geometric element. A geometrical-relation constraint is defined corresponding to the type of surfaces and its geometrical relation. The relationship between the form tolerances and the geometrical-relation constraint is also described in each movable element for interpreting the change of form tolerance into that of the geometrical-relation constraint. In the prediction process of parts deterioration using the geometrical quality feature, the effect of the deteriorated deformation on the functional behaviour is calculated using the cause list and behaviour simulation. This calculated status is assigned to each geometric element through form tolerance and it refers to the prediction of the deteriorated status comparing to the usage history. Through this process, the reuse of mechanical parts as a material for the machining process can be supported.