Interference between Parts of a Mechanical Assembly Contained in a STEP File

Abstract

Obtaining interferences among parts of a product contributes to determine the feasibility of the assembly sequences according to the geometry of the parts involved. However, in assembly may exist partswith freeform surfaces which make difficult to determine the interference relationship between themautomatically. The objective of this research is to present a method for obtaining interference among assembly parts with prismatic, cylindric and form free surfaces. The method is automated with a software developed on PythonOCC open source framework, which is based on OpenCascade. The techniques for extracting assembly geometric information which is contained in a 3D CAD file withSTEP standard format, the detection of collisions between the parts in disassembly directions, and the generation of interference matrices are described. Two examples of mechanical assemblies are analyzed to demonstrate the effectiveness of the method and the interferences matrices corresponding to the six principal axis disassembly directions are obtained as a result.