Abstract: Geometric dismountability (GD) of component is the premise for assembly sequence planning based on “acquire assembly by disassembly”, while interference matrix is an essential assembly relation model for determination of GD. To solve the problem of GD determination in the directions not parallel to the standard orthogonal coordinate axes, extended interference matrix (EIM) is proposed, whose structure is extended to directions of local coordinate axes of each component. To facilitate analysis of GD of component with multidirectional disassembly path, turning interference matrix (TIM) is proposed, whose structure is compact enough to describe the complete interference information from the turning point. Several methods for generating EIM and TIM rapidly and automatically are presented, including precise stepping-detection, coarse detection and accelerating detection based on bounding-box. The method for refraining static hard-interference automatically is also studied. A more comprehensive algorithm for determining GD based on EIM and TIM is then presented. An assembly planning system “AutoAssem” is developed based on UG NX platform, with the examples illustrating the effectiveness of each interference detection measures. EIM and TIM are testified to enrich the variety and variability of disassembly directions, which provide GD determination for complex production with great commonality, and provide subsequent sequence planning algorithms with effective foundation.

Key words: Assembly sequence planning, Extended interference matrix, Geometric dismountability, Interference detection, Turning interference matrix