AUTOMATIC ASSEMBLY SEQUENCE GENERATION

Abstract

Assembly Sequence Planning (ASP) is part of Assembly Planning. It has been experienced that around 40 percent cost of the product is involved into the assembly process. Therefore, optimization of assembly sequence is necessary to ensure the minimization of cost of final product. In this work we have worked on the formation of automatic assembly sequence (optimized) generation. This work is divided into three steps. In the first step the interactive data of assembly is taken from CAD model. This data is used for part — part (liaison) matrix. The precedence relation information is taken interactively. The methodology for accurately taking the precedence relation information is developed. In the second step, all the possible subassemblies are determined. A case study of industrial product having 25 parts is taken. For the determining subassemblies, algorithm has developed which uses the liaison matrix as well as precedence information matrix and generate all the feasible subassemblies. By using experience and the previous work we proposed the rules for the formation of subassemblies. Once all the subassemblies and individual parts are determined, then using Jonson-Truttor algorithm all possible sequences are determined. Finally from all possible sequences practically feasible sequences by using precedence information are generated. From all practically feasible sequences optimum sequences are selected by using the optimization constraints like reorientation, weight, priority preference operations, assembly time, assembly cost. The whole programming is done in Visual C++, run on the Pentium 4 desktop, 1 GB RAM. The results are quick and there is no possibility of probability less than one in any example of assembly, as it is most possible in genetic algorithm, fuzzy logic technique used for assembly sequence generation.