Reduced cycle time and work in process in a medical device factory : the problem and a proposed solution

Abstract

Many manufacturing firms have improved their operations by implementing a work-in-process (WIP) limiting control strategy. This project explores the application of this concept to limit WIP and reduce cycle time for the Becton, Dickinson and Company's manufacturing facility in Tuas, Singapore. BD's Eclipse Safety Needle production line is facing increasing pressure to reduce its high WIP and long cycle times. With the forecast of increasing demand, the current production control practice will sooner or later push the shop floor space to a limit. We divided the overall system into three manageable sub-systems and analyzed different strategies for each. This paper documents the approaches to Needle Assembly machine (AN) and downstream machines, as well as the inventory policy for Needle Shield (NS) and Safety Shield (SS) molded components. At AN and downstream, we can achieve significant reduction in cycle time and work in process by eliminating the unnecessary early start of production and extra delay caused from the current planning method, by reducing transfer batch sizes and by applying mixed scheduling policy at AN. We can obtain further improvement by implementing a CONWIP release rule. For the stocking of NS and SS molded parts, a simple periodic review, base stock inventory policy can effectively reduce the current inventory level by more than 40%, as well as reduce the inventory variation.