A Multi-Constraint Assembly Registration Method Based on Actual Machined Surfaces

Modern manufacturing places increasing demands on assembly accuracy, revealing the limitations of conventional tolerance-based methods and studies that oversimplify multi-surface constraints into single-surface problems. To address this challenge, it is crucial to account for geometric distribution errors on multiple surfaces and constraints from multiple mating surfaces, analyzing their coupling effects in assembly. This paper presents a model that incorporates the effects of machining-induced geometric distribution errors and the constraints arising from multiple mating surfaces. The model determines contact points between two pairs of mating surfaces and calculates the spatial pose of the assembled part to predict assembly accuracy. The model validation was conducted in two stages: initial verification of fundamental principles through a two-dimensional simulation, followed by experimental validation. The experimental study involved mating surfaces with distinct geometric distribution errors manufactured by different machine tools. Assembly tests were performed under two distinct orientations of applied external forces. Results show close agreement between predicted and measured values, with a root mean square error (RMSE) below 2%, confirming the method’s effectiveness. The proposed method offers a solution to the assembly registration problem involving coupled multi-constraints and geometric distribution errors.