Simulation of a manual order picking system in a convenience store chain distribution center

Abstract

The manual order picking system is a common process in warehouses that fill orders and refers to the collection of items and / or materials requested by customers. It is a fundamental task that affects the total operating costs of a supply chain, so it must be performed efficiently to ensure that the needs of the customers are met. The following work presents a case study in a manual order picking system to supply a chain of sixteen convenience stores, in which the orders of around twenty products are ready for dispatching to stores every day. The objective of the study is to determine the number of order pickers needed to ensure that delivery of all orders to stores is met, and that the expected time to have an order ready for dispatching to the customer is three hours maximum. In order to accomplish this objective, a FlexSim discrete event simulation model was developed. Simulation modeling has proven to be a powerful tool to size the amount of human resources needed to comply with the customer service policies established by companies. Simulation results indicate that with the current number of order pickers, a 91.5% service level has been provided by the distribution center, in terms of the number of dispatched orders to the convenience stores daily. Moreover, a total of 16 order pickers are required to have an order ready for dispatching in a period of three hours maximum.