The Hybrid Heuristic System in Balancing the PCB Assembly Line of Surface Mount Technology with Multiple Placement Machines

Printed circuit boards (PCBs) are extensively used in diverse electronic products today. The placement process is generally the bottleneck in a PCB assembly line. Many researchers have indicated that an optimal component placement sequence reduces the cycle time of an assembly line with single placement machines. However, in current PCB assembly lines, more than one placement machine, including Pick-and-Place and Chip Shooter machines, are concurrently used. Therefore, in the PCB assembly lines with multiple placement machines, the improvement of a single placement machine is no longer an issue in increasing throughput rate. The line balancing tasks within machines has a greater impact on the throughput rate. This research uses a hybrid heuristic approach in designing a prototype system to implement line balancing tasks within the multiple placement machines of a PCB assembly line. First a minimum spanning tree algorithm is introduced to solve the problem in allocating components to various feeder slots. Then, by incorporating with the initial results of this step, a mathematical model is developed to solve the line balancing problem faced in the assembly line. The developed line balancing model uses the combination of formulations and experts' reasoning knowledge to rearrange the component groups which are placed by the placement machines. The proposed system model is used to construct a prototype system that assists the process planners to reduce the cycle time of the assembly line so as to increase the throughput rate.