Implementing JIT Philosophy in Push Based Production System

It is commonly known that implementing JIT philosophy in manufacturing environment involves a pull mechanism like Kanban card. However, one of the underline JIT principles focuses on creating and keeping stability of production system. Therefore, by sensing the production system status before making decision on releasing new work order into the system can be applied and achieve JIT philosophy without implementing pull mechanism such as Kanban which requires a significant change in several areas in production system. In this article, CONWIP (Constant Work-In-Process) concept is applied in tradition push based production system where MRP (Material Requirement Planning) is utilized as key control mechanism. In order to validate the impact of CONWIP concept, simulation model of case study production line is developed in order to take consideration of stochastic nature of the production process in evaluating the performance of CONWIP production system. As a result, CONWIP based production system outperforms current push based production system. In addition, the CONWIP’s control parameters are also developed based on the statistical relationships between system throughputs and those controlled parameters. Then, a production planning framework is developed to provide guidance in setting appropriate parameters based on production status. Also in CONWIP controlled system, production planner can accurately predict the job’s delivery time.