Improving Daily Total Complete Shipment by Using System Dynamics Simulation in an Indonesian Car Spare Parts Manufacturer

PT. Nusahadi Citraharmonis is a leading manufacturing company in Indonesia that produces spare parts for various automotive industries. The company is an active supplier for several well-known car manufacturer in Indonesia, which are: NTC, HMMI, TMMIN, and ASKA. However, the company is currently having difficulty in fulfilling all customer demand on time. Thus, creating backlogged order in the system and decreasing the daily total complete shipment. The objective of this research is to redesign new inventory level to increase the daily total complete shipment. To solve the problem, Define-Measure-Analyze-Improve-Control (DMAIC) is used as the procedure, cause effect analysis is used as a tool to identify the key factors affecting daily total complete shipment, and system dynamics simulation is used as a tool to redesign inventory level. From the result of system dynamics simulation, the newly redesigned inventory level is able to decrease the backlogged order in the system and increase the daily total complete shipment. Besides the system dynamics simulation, standard operating procedure for operating the system is also made and given to the company for future use.