Study On Hybrid Remanufacturing/Manufacturing Inventory Control System Based On PULL Strategy

In recent years, with enhanced environmental awareness of people as well as the introduction of environmental regulations, recycling waste products has gained more and more attention. This led to manufacturers should not only concern the forward logistics which is from the supply of raw material to the product delivery to the customer, but also re-manufacture of waste products arising from the issue of reverse logistics, which formed the R/M (re-manufacture/manufacture) hybrid systems. And inventory control is one of the key issues which re-manufacture/manufacture hybrid system need to solve.In view of the situation that the manufacturers responsible for product's reuse after being remanufactured. The paper introduced Markov decision theory to the research of the inventory management problems in re-manufacture/manufacturer hybrid system based on PULL control strategy, which is an innovative exploration. The paper came to the optimal control strategy by setting out Markov decision process model based on PULL inventory control strategy with and without the production lead-time condition and proved its superiority by the example analysis.The paper's work is mainly reflected in the following aspects:(1) The paper created MDP model based on PULL inventory control strategy R/M hybrid system and then got the optimal control strategy. The model use Markov decision process theory as foundation, use periodic product as decision variable and use available inventory in current period as state variable. On this basis the paper analyzed changes of optimal number of manufacture (purchase strategy) in every situation and finally got the optimal control algorithm. At last the paper proved PULL strategy is superior to PUSH strategy by making a comparison of PUSH and PULL strategies' influence to the total inventory cost performance through analyzing numerical examples.(2) Taking into account the non-zero production lead time and safety stock, which are more fit the actual operation situation. the paper made the R/M hybrid system MDP model based on PULL inventory control strategy consider, whose lead time is L and then got a optimal control algorithm under the new conditions. The paper got the change of optimal number of manufacture (purchase strategy) in two situations that available inventory is different from demand by two proofs of the model property. Finally, the paper provides enterprise with proposed reference of management by the comparison to model total cost under non lead time situation and analysis of factors which can affect cost and control strategy in lead time situation.