A hierarchical optimization method in the PCB assembly for surface mounting machines

An hierarchical optimization method to improve efficiency of the surface mounting machines (SMM) in PCB assembly is presented. To minimize the setup time, an automatic CAD data conversion system and a database system of components are proposed, which automatically generate the data for pick and place sequences from the CADSTAR output files. For maximization of the efficiency of operations, an effective assignment algorithm for heads and nozzles and an effective arrangement algorithm for feeders are proposed. Finally, a modified effective heuristic algorithm for traveling path of heads is also proposed, which is based on the traveling salesman problem (TSP) solution technique. The proposed algorithms are tested through simulations on the assembly tasks of PCBs actually manufactured. It is shown that the proposed algorithms reduce the time required to perform the assembly sequences by up to 40 percent compared to the randomly generated sequences