21. Production Planning for Make-to-Order Flow Shop System Under Hierarchical Workforce Environment

In make-to-order system orders are scheduled for production based on the due date agreed with customer and the strategy of company. Production planning of such system includes scheduling of orders to the production periods and allocation of workers at different work centers. Complexity in the system arises when the operation to perform next and its processing time is skilled dependent where a higher qualified worker type can substitute a lower qualified one, but not vice-versa. Under such working environment, efficient scheduling of orders and allocation of workers at different work center play major role to improve system performance. This paper develops a mathematical model for make-to-order flow shop system under hierarchical workforce environment. The model helps identify optimum schedule of orders and allocation of workers with an objective of minimizing the weighted average earliness and tardiness. A heuristic method is also proposed to overcome the complexity of mathematical model and solve the problem efficiently. Numerical analysis indicates that proposed heuristic is capable of finding optimal or near optimal solution in a considerably reduced amount of computational timing.