Heuristic interpretation of infeasible solutions to a production scheduling problem in cigarette manufacture

In this paper an end-user Infeasibility Resolution Heuristic (IRH) is developed to assist managers and production schedulers in the evaluation and interpretation of infeasible solutions arising from the use of a production scheduling model of a tobacco processing plant. The primary aim of the model is initially to determine whether the forecast annual demand for tobacco products can be met by the plant, and if not what must be done. Having determined that the demanded quantities are feasible, the model is then used to arrive at a production schedule such that the minimum number of machines are used in the entire process for the planning period (the model is a monthly one linked together by the closing stock equations for up to 12 months ahead). The operations of the plant modelled include the selection of the appropriate blend of leaf, assignment of the forecast product demand to suitable making machines, production of the required quantity of filters, assignment of the cigarettes produced to specific packers and then the determination as to whether the final product produced in the current period will be used to satisfy the current month's demand or demand in the future. The problem of sequencing the monthly production once the production schedule is determined has not been dealt with in this paper.