A Study of Mapping the Planeness to Dimension Chain for Assembly Tolerance Analysis

Fits of flat surfaces is one of the most popular ways for parts assembly, and the planeness of the flat surface would affect the assembly accuracy. In order to analyze the assembly error stack including planeness, a tolerance cell based on feature and digraph is proposed to represent the tolerance. And the tolerance model of the assembly component is established by combining the tolerance cells by using feature constraints. Based on the assembly tolerance model, the surface planeness could be decomposed into translation and rotation of the part to assemble in the following step. The translation and rotation of the part are mapped into the vectorial dimension chain when establishing the chain. A wing component assembly of a special aircraft is chosen to validate the proposed methodology. And the result shows that the surface planeness can be treated properly. It also provides some references for carrying out tolerance analysis of shape and location.