COMPONENT TO MULTI-TRACK FEEDER ASSIGNMENT AND BOARD SEQUENCING IN PRINTED CIRCUIT BOARD ASSEMBLY
Journal of electronics manufacturing
approved: Sabah U. Randhawa This research was motivated by the use of multi-track feeders in the printed circuit board (PCB) assembly. In a low volume, high mix production environment, setup time is usually considered more important than processing time. Implementation of multi-track feeders not only increases the capacity of the surface mount machines but also reduces feeder changeovers. However, improper planning could diminish these benefits. The objective of this research is to develop a
... cess plan to minimize the feeder setups in multi-track feeder systems. Two problems have been identified: component to multi-track feeder assignment problem and PCB sequencing problem. The assignment problem is formulated as a multi-dimension symmetric assignment problem with an integer-programming model. The objective is to maximize the total similarity of the component assignment. This optimization model is implemented for small-sized problems using a commercial solver package. Due to NP-complete characteristics, heuristic algorithms are developed for solving large-scale problems and industrial cases. The Hungarian algorithm, designed for asymmetric assignment problems, is used to reduce problem size in the double feeder case. The PCB sequencing problem is solved in three stages: component and PCB grouping, intra-and inter-group PCB sequencing, and feeder setup planning. An optimal tool switch policy called Keep Tool Needed Soonest is adapted for planning the multi-track feeder setup. This research also identifies the interrelationship of the assignment problem and PCB sequencing problem. An optimal component to feeder assignment will show real advantages only when working with a well-planned PCB sequence. Data obtained from literature are used to verify the heuristic developments. The methods are also applied to industrial data for evaluation of performance of real-world problems. Experimentation is conducted with simulation data to investi gate the performance of methodology for different production situations. The results show that savings of up to 85% in feeder setups can be realized with a double feeder system compared to a single feeder system, with the use of the developed methodology. The approach is also robust and efficient for different production environments.