Research And Applications Of Cut-sets Theory On Mechanical Assembly

During the assembly of the products, the priority in the assembly of spare partsplays a decisive role in the assembly in terms of quality and efficiency. According asproduct complexity improves and the production cycle reduces, the achievement of aquick and efficient assembly sequence is inevitable requirement for the improvementof enterprise competitiveness. As a matter of fact, the automatic generation of productassembly sequence which is on the basis of cut-set theory, has important theoreticalsignificance and engineering application valueTaking numerical control lathe spindle unit as research object, the productassembly model is built and the method of graph theory is used to express the productassembly model; the method of combing the connection between the cut set in thegraph theory and the spare parts of the assembly with their constraint relationship isadopted to automatically generate the whole assembly sequence. Finally, Extensionanalytic hierarchy process is used to evaluate the assembly sequence.First, the assembly model of the assembly is established, including the relationmodel and the hierarchical model. The relation model is expressed in the undirectedliaison graph. Under the assumption that the assembly sequence and the disassemblyis inverse, the whole cut set of the liaison graph is solved, and the feasibility of the cutset is confirmed which will reduce calculation amount and increase efficiency byeliminating those unfeasible cut-set. Finally, all the feasible assembly sequence isshown in AND/OR graph. AHP method is used to evaluate the assembly. The result ofthe assessment shows directly the advantages and disadvantages of each assemblysequence so as to provide reliable basis for the actual processes of production andassembly.