Many Varieties Service Parts Inventory Control

With the globalization of production and increased competition, how to manage the service parts inventory effectively has become a concern of many manufacturers. The traditional economic order is the most well known model, however, it's no longer suitable for the service parts inventory management because of the characteristics of service parts. First, with the aging of products, the obsolescence risk of service parts increase fast, so different from the product, the service parts order quantity is affected by the life function, and depends on the order moment. Second, the species of service parts are too many, manufacturing service parts are almost 20 times of the finished goods, their value are different too.Based on former research, the paper researches the inventory strategy of multi-item service parts based on different conditions. The research contents of the paper can be concluded as follows:1,Firstly, the paper outlines the related research work, the research significance, and the service parts characteristics. Then, it analyses and compares the research statue on service parts at domestic and overseas. It summarizes the current problems on research, and points out feasible research directions.2,This chapter studies the inventory of multi-varieties service parts base on service level and certainty of life-cycle. The paper assume the life of service parts for exponential function, it's useful for the short lifetime service parts. But it assumes the obsolescence risk is constant, and this is the limitation of this chapter.3,This chapter studies the inventory of multi-varieties service parts under the condition of storehouse capacity and has the repair rate restraint, and presents the optimal policy of storage. Finally the model proves to be effective whether to rent the warehouse or not through an example.4,In view of multi-item and uncertainty of life-cycle, the inventory of multi-item service parts based on trade credit and function of life-cycle was studied. According to the value of trade credit period, two EOQ models with order cost, inventory cost, interest earned, interest payable and obsolescence cost were constructed. Also, the effect of credit period length and obsolescence risk on the firm's optimal strategy and annual total cost is examined.