Discrete Event Simulation-Based Collation System Analysis in Mail-Order Pharmacy Automation System

摘要

This paper presents an analysis of collation systems with different configurations in mail-order pharmacy automation (MOPA) systems by developing discrete event simulation (DES) models. In a MOPA system, one of the most important factors that impact the system productivity performance is collation delay, which is defined as the waiting time for an order from the first item arriving at collation station until the last item arrives. Therefore, the research objective is to optimize the collation solution to minimize collation delay and improve the system throughput. Specifically, two collation systems: collation loop and collation robot are tested and compared through DES models. Multiple demand scenarios are tested and analyzed in this research, which is differentiated by 1) fill time window (FTW), 2) order quantity, and 3) order size distribution. FTW is the time from the first item leaving the filling station until the last one item in one order. Three performance metrics are used to evaluate the system, 1) collation delay, 2) number of items in loop, 3) number of tubes being used in collation robot. The result shows the collation robot system achieved shorter collation delay than the collation loop.