A heuristic algorithm for loading new work on circuit pack assembly lines

SUMMARY

This paper describes a scheduling algorithm used to suggest the sequence in which new products should be started on circuit pack assembly lines. For a real application many aspects, such as inaccuracy of data, incomplete information, variability and unpredictability of many events, etc., make it very difficult to have a realistic model which is analytically tractable. The scheduling approach developed here is an effort to capture the right details and to leave an allowance for the aspects not represented in the model. It shifts the emphasis from optimization with’ idealistic models to a conservative approach with more realistic models. A combination of heuristics are used to achieve the objectives of meeting weekly due dates, of keeping W1P, flow time and number of set-ups low while maintaining capacity. Due dates are given the highest priority. Within the limitations imposed by due dates, a weighted, cumulative load imbalance measure is used to balance the load on all operations. Set-up considerations determine the choice if this measure is close to (say, within 15% of) the minimum. This provides a simple, robust and reasonably sound solution to an enormously difficult problem.