Subassembly generation algorithm from a CAD model

Abstract

Assembly or disassembly sequence planning is a very hard combinatory problem while the assembly parts numbers become important. To reduce this difficulty, especially for the case of complex products, the subassembly identification concept can constitute an original way. It aims to decompose the complex assembly product into some subassembly entities containing a small number of parts. Consequently, the generation of assembly or disassembly sequence planning of parts becomes between the subassemblies and, in that case, can be determined relatively easily. Despite the prettiness of the subassembly method, the identification of subassembly from a computer-aided design (CAD) model remains a relevant research subject to be improved. In this paper, a subassembly identification approach is presented. The proposed approach begins with the exploration of the CAD assembly data to carry out an adjacency matrix. Then, to identify the subassemblies, the extracted matrix is transformed through three steps. The first step consists of idealizing this matrix by removing all connection parts identified by the Feature-Manager, which permits reducing its size. Afterward, based on the reduced matrix, an all-direction matrix is constructed to identify the base part of a subassembly. The third step consists of enriching the all-direction matrix by mounting conditions to construct the set of subassemblies. An example of a CAD assembly mechanism is presented in all sections of this paper in order to explain and discuss the steps of the proposed approach.