Deviation modeling of manufactured surfaces from a perspective of manufacturing errors

Abstract

Assembly analysis, as an important step in the product design stage, provides verifications of product design with specific requirements. The manufactured surfaces that participate in the analysis result from different manufacturing methods and show inconsistency with the designed surfaces due to the effects of numerous manufacturing errors. These deviations have a vital impact on the assembly analysis results and make a big difference on the final product design process. Therefore, consideration of such manufactured surface deviations in assembly analysis is critical in order to achieve an effective product design. In this paper, a general surface deviation modeling and representation approach based on curvilinear coordinate system is proposed. Different curvilinear coordinate systems for various manufacturing methods are defined on nominal product surfaces. By introducing the deviation dimension in the orthogonal direction of the curvilinear coordinates, deviation coordinate systems are formed. The deviation coordinate system could be used to describe deviation surfaces resulting from numerous manufacturing errors with deviation functions. As an example, non-ideal planar surfaces in the face milling process are modelled with the proposed method. With the generated non-ideal planar surfaces, the sealing performance analysis of an assembly is implemented. The validity of the proposed method and its applicability in simulation are verified in the end.