Studies On The Economic Lot Size And Flow Rate Control Model For Production Systems

Production lot sizing problem is one of the most important subjects in the fields of manufacturing industry production and business management. It is hot research area of the inventory control that how to cut down the production run cost, reduce the inventory occupancy capital and accelerate flow of fund. The common used method is to apply the traditional economic production quantity(EPQ) or economic order quantity(EOQ) and determines the procur-ing lot of all kinds of raw materials and production lot of all kinds of products. The economic quantity that is calculated according to the traditional inven-tory control models is larger since they have many assumption conditions that disagree to the production practice. This paper extends the tradition EOQ model and EPQ model such that the traditional inventory control model is more close to the stock management reality.First, on the classical EPQ model, we present a practical inventory model with permissible delay in payments and allowable shortages, and obtain the optimal replenishment lot per cycle. For a deteriorating production system in which the time to shift from an in-control state to an out-of-control state is assumed to be a general shift distribution, we propose a new product inspec-tion policy, and discuss the properties of the optimal product run time and the corresponding inspection policy. We also probe into an optimal periodic production policy for a failure-prone production system with two production state (in-control state and out-of-control state) and a failure state. We ob-tain the optimal expected lot sizing and the properties of the optimal periodic production run time.Furthermore, we use the continue flow model with a more direct physical significance to describe the production systems in processing industry, in which production systems in processing industry are studied being one failure-prone machine, and extend the classical flow control model. Considering the ma-chine maintenance rate as a control variable and the inventory deterioration, respectively, we study the optimal production policy for the flexible manufac-turing systems with multiple failure mode and multiple product. When the age of the machine and preventive maintenance are considered, we study the maintenance scheduling and production control problem for the non-flexible production systems with not frequent setup.