A Simulation Model to Optimize Pre-sewing Operations in the Apparel Industry: A Case Study from Sri Lanka

Abstract

Themost crucial factor in apparel manufacturing is catering for due dates. The unoptimized, ad-hoc scheduling and static routing of Production Orders (POs) result in late deliveries of orders. The inability to analyze the available presewing capacity against the demand results in last moment revelation of resource over utilization. This study proposes a systematic approach in analyzing pre-sewing capacity against the demand.A mathematical model in estimating pre-sewing job completion times for six chosen pre-sewing departments is proposed. Operation Flexibility and Routing Flexibility in presewing section are analyzed and integrated in scheduling through Precedence Diagramming Method (PDM) and priority scheduling algorithm. An optimized scheduling approach with a simulationmodel to facilitate the visibility of resource utilization and PO completion times is adopted. The simulation model provides approximated PO completion time with optimized criterion, provides measures on resource utilization and queue wait times, thus facilitating proactive measures for the management at an early stage of the production.