Optimization On Scheduling For Printed Circuit Boards Assembly Lines

Printed circuit board (PCB) with insulation board as basic material, completes point connection and prints the electronic components according to design. The assembly system of printed circuit board is known as surface mount assembly system, with both computer integrated manufacturing and flexible manufacturing and other advanced manufacturing system characteristics, mainly in the application of Surface Mount Technology (SMT). At present, the printed circuit assembly industry is in small quantities and multi-types production environment. Only in the shortest time with minimal defect and cost to obtain the maximum output, it is to adapt to production requirements of many varieties, multitasking and multi-user. Therefore, there is important practical significance in SMT line optimization design study on the PCB board.The main work of this paper is the optimization modeling in the SMT production line scheduling problem on PCB board, divided into the following three levels:The first level is the production optimization of single type PCB board in single chip mounter, including three optimization subproblems:suction nozzle allocation, feeder assignment and component placement sequence, respectively using clustering algorithm, sequential traversal algorithm and combined with sticker set assignment.The second level is the production optimization of PCB board in single production line. The optimization in a single production line of single type PCB is mainly to optimize the load balance of components in the placement machines, and this paper uses the genetic algorithm to shorten the production time. The optimization in a single production line of multi-types PCB includes PCB packet, variety switching and other optimization subproblems. In this paper, it uses similar relative coefficient group strategy to divide the PCB into different groups; component feeder uses the KTNS section switching strategy to switch. Using active taboo search algorithm sorts for PCB among different groups and in the same group, so as to optimize the production.The third level is the production optimization of multi-types PCB board in the production lines, which is the optimization of multiple varieties PCB board in two production lines. It is to assign various PCB to two different production lines in a balance way. This paper makes further improvement of similar relative coefficient group strategy to similar the PCB boards in two production lines, so that the completion time of two lines is as close as possible. The target of production optimization is to make sure the maximum average flow time of two production lines the shortest.