Optimization of spare parts based on inventory level and turnaround time

This paper addresses the issue of determining the single item inventory level and turnaround time to make system expected backorders achieve the optimal with marginal effect analysis. First, the objective function of system expected backorders is created under cost constraint, and its characteristics are analyzed. Next, the solution to the model will be developed in two steps: for a single first-indenture item, the method of marginal effect analysis is developed to weigh inventory level and turnaround time to make its expected backorders minimum; in order to make the system expected backorders achieve the optimal, all items which are combined in a system are analyzed with marginal effect analysis. Finally, the credibility of optimization model is validated through particular case applying.