A Simulation on Unloading, Loading and Warehousing to Reduce the Waiting Times of the Processes

Abstract

Loading, unloading and warehousing are three critical processes for a manufacturing organization. Therefore, reducing cycle and waiting times related to those are vital in improving its performance. This study aimed to investigate such bottlenecks in a loading, unloading and warehousing system in an apparel manufacturer in Sri Lanka to provide necessary solutions for them. The selected system included two bays entirely dedicated for unloading and one bay also for loading processes. After the eighth hour of a 12 hour working day, the loading process was done for finished products. Also this was given the priority when hefty waiting times in the unloading process were existed in simultaneous running of both processes. The study observed arrival and service times of each container and its batch for three consecutive weeks. The inter-arrival times were then calculated and two possible were identified to optimize the efficiencies of the processes. Accordingly, the study suggested an addition of loading process and more resources for the bay dedicated for loading process. Thus both alternatives were simulated using Rockwell ARENA and performance was analyzed. The results showed percent of reductions in unloading waiting times to be 57.5, 79.6 and 90.2 respectively in bay one, two and three with the addition of more resources for the existing bays. Correspondingly, the warehousing times were reduced from 69.88, 72.90 and 42.45 percent. The loading waiting times reduces up to 100 percent in the same simulated model development while the addition of another bay does not. Thus, the findings of the study selected the resources addition to be the optimum of the two alternatives.