Optimization of component placement scheduling for SMT assemblies

The surface mounting of electronic component is the major manufacturing technology for the electronic products in the last decade. The surface mounting technology (SMT) is an assembly process that assembles the surface mountable component (SMC) and the printed circuit board (PCB) together. The SMT mounter is an automatic assembly machine that processes the SMT assemblies in terms of the optical positioning and robotic handling. The SMT assembly consists of calibrating printed circuit board (PCB); vacuuming components form feeder stations; compensating the orientation of the vacuumed surface mountable component (SMC); and finally placing SMC chips on the PCB. In order to increase the throughput, the synchronous batch vacuuming of SMC components is designed. In addition, different types of component feeding and mixing in each batch increase the difficulties of finding the best component mounting sequence. In this paper, the optimal component placement scheduler is desired to perform higher assembly performance and to reduce the cycle time. The proposed optimal component placement scheduler is developed based on the rule based heuristic search approach. In addition, to evaluate the cycle time of each heuristic search, the route oriented Petri nets (ROPN) based SMT assembly models are constructed. The optimal component placement scheduler can be further determined in terms of evaluating the ROPN SMT assembly models. Finally, the practical test PCB board data is discussed in this paper.