Study Of Tolerance Analysis Method Based On Matrix Transformation

Along with the development of modern manufacturing industry, the quality of products becomes more and more important in the competition among enterprises. Since complicated products are made of many parts, the quality is largely depended on the assembly accuracy of key characteristics. Therefore, the prime task is to improve the quality of products by machining accuracy and assembly accuracy management in order to improve the competitiveness of manufacturing enterprises. Tolerance analysis is the core of accuracy management and a lot of work has been done in this field by scholars both at home and abroad. Engineers can find the defects in the tolerance design and process design stage before making prototypes. Moreover, the development time and the manufacturing cost will be decreased at the meantime.The thesis proposes a systemic 3 dimensional tolerance analysis method in which the homogeneous coordinate transformation matrix represents for 3D assembly error and the matrix operation is used in tolerance analysis. The major work is as follows:(1)The previous work in tolerance analysis field is surveyed, and the advantage and disadvantages of those former study are concluded and a tolerance analysis method;(2)A new assembly model is proposed, providing the parts information, assembly feature information, constraint relation of parts and fitting relationship information, with which to generate the error accumulation route;(3)The feature tolerance model is established according to the matrix transformation method characteristic. The shape and position tolerance in the engineering drawing can be transformed into a special tolerance type that can be used directly in tolerance analysis method is put forward;(4)The Monte Carlo method is used to simulate product manufacturing process and take random error value for all the tolerance of the features; (5)The influence of the feature's deviation on assembly's key characteristics is studied, with the homogeneous coordinate transformation matrix representing for 3d assembly error;(6)The error accumulation result is analyzed and the analysis result for product tolerance optimization is also evaluated.