Modelling the spare parts stock levels and its applications in industrial systems

This paper addresses a practical decision making by developing an innovative inventory and transportation cost model to determine the optimum number of the spare parts and its location in the warehouses subject to run-in, random and usage failure inside a maintenance network. The spare parts slow moving items inventory management is a complex problem. The demand is sporadic and difficult to forecast, the utilisation is specific, the part economic value is high, the failure causes system downtime costs and normally this complexity is compensated by overestimated the part inventories. The proposed procedure can be used to determine the spare parts stock level and allows to minimise a function cost sum of aggregate inventory costs and downtime production plant costs caused by the parts failure and transportation from the storage areas to the user or machines failed. Four real case studies from different industrial application projects are illustrated in order to demonstrate how to apply the proposed model into real world applications. The results and findings from such industrial applications are found useful to engineers and managers in industry.