Computer aided angular tolerance charting system: Implementation

Tolerance charting is one of the important technologies used in process planning to develop the mean sizes and tolerances of the working dimensions for a new manufacturing process, or to analyze a set of existing dimensions and tolerances to determine if the component can be made to meet the blueprint specification. In this paper a computer-aided angular tolerance charting system is implemented, which is mainly based on the mathematical models of the algebraic method for both square shouldered and angular features. A surface changing algorithm is applied to calculate the working dimensions. The process tolerance allocation is carried out with a discrete interval cost-tolerance model and a multi-choice knapsack model. With a genetic algorithm, an optimal or a near-optimal solution of tolerance allocation is achieved consequently. The implementation of such a computer-aided angular tolerance charting system is presented from the viewpoint of software engineering. The data structures for blueprint information, operation information, and tolerance charts are designed. The functions of the angular tolerance charting system are described. The prototype of the system is analyzed in detail.