Entropy-based method for evaluating spatial distribution of form errors for precision assembly

Accurate evaluation of form errors is an important part of precision assembly. On the microscopic scale, there are peaks and valleys of different sizes that are non-uniformly distributed on the surface. Different from the traditional minimum tolerance evaluation method, this paper proposes an entropy-based method for evaluating the spatial distribution of precision assembly form errors. In this method, information entropy is applied to evaluate the three levels of form error height distribution, and the nearest neighbour index technique is used to check the position distribution. Two experimental machined surfaces were used for testing and error matching was used to verify the proposed evaluation method. The results show that the method is reliable and effectively evaluates the spatial distribution of form error, which provides new insights for shape error evaluation and lays a new foundation for evaluating assembly accuracy and contact performance.