Determination of Production Start Time for Inventory Storage Space Minimization

The research explores a production scheduling problem in a system where multiple items are manufactured on a single production line on a rotating basis. The objective is to identify the proper production start time for each item within a predetermined production sequence by strategically inserting idle time between the production of consecutive items to minimize the maximum required storage space. A mathematical model and the Idle Time Insertion for Storage Space minimization (ITISS) constructive algorithm are presented. The performance of the ITISS algorithm is evaluated on 300 randomly generated problems across five different problem sizes (10, 20, 30, 40, and 50 items) and two slack time levels (0.01 and 0.03 years). The ITISS algorithm provides optimal solutions for all 300 experimental problems with more than a 99% reduction in computational time compared to solving the linear programming model. In comparison to consecutive production schedules, production schedules with optimized start times can reduce total inventory storage space by 13.81%. This reduction is more emphasized in the production system with larger slack time.