An evaluation method for spatial distribution uniformity of plane form error for precision assembly

This paper presents a method to evaluate the uniformity of planar spatial distribution considering form error. At the microscopic point of view, there are numbers of convex hulls and valleys with different sizes and shapes, which are non-uniformly distributed on the surface. Different from the traditional evaluation method of the minimum tolerance, this paper presents an improved method based on the preliminary evaluation of the plane form error using information entropy. The information entropy is used to evaluate the uniformity of the amplitude (height) distribution of the convex hulls. The nearest neighbor index is used to evaluate the uniformity of the position distribution on the surface. Then, taking two actual machining planes as an example, the validity of the evaluation method is verified. This method provides a new idea for the form error evaluation, and establishes the basis for the evaluation of assembly accuracy and contact performance.