Optimal Dispatching in a Periodically Review in On-line Manufacturing System with Vendors Evaluation

This paper, we consider dynamic dispatching control of a fully flexible online manufacturing system. Hence, vendors, who supply the materials, play an important role in this system. So, selection of vendors is much important. In a periodically reviewed, online manufacturing system where materials are dispatched from a central control station to different manufacturing sales. After production process, the parts are routed to inspection and quality control room. Hence optimal dispatching policies are pursued to minimize the in-process inventory carrying / holding cost over finite horizon. A dynamic programming formulation is developed for optimal dispatching which shows that the dynamic recursive functions (i.e. cost to go function) are convex and monotonic under the condition of low defects rates and relative low cost material handling. From the derivation we conclude that optimal dispatching sales for a combination of zero inventory and Nonzero inventory policies. Thus, the optimal input control is proved to be in the form of a pulling system. Keyword: online manufacturing system, material dispatching control, in-process inventory, vendors evaluation, monotonic properties.