An Integer Linear Programming Model for Herbal Cosmetic Production Planning

Abstract

This paper addresses a problem related to the production of herbal cosmetic products. Multiple herbal cosmetic products are produced under batch production and require different amounts of processing time. Sometimes the output does not match the customer demand, or the customer demand exceeds available capacity and inventory of the process. The entire out-of-stock of goods is assumed to be the backorder. Moreover, a manager must appropriately assign workers to tasks not only according to their skills but also to the workload balance. For this reason, an Integer Linear Programming (ILP) model has been developed to minimize the total cost of the process; this includes material, inventory, backorder, production, and labor costs. The results showed that the total cost of operation under the production plan generated from the ILP model could be reduced by 5.06% compared with that under the current production plan.