Repairable items inventory optimization based on maintenance data and risk criteria

Abstract

The performance of organizations has a strong dependence on the successful operation of their physical assets and this is based on a large scale in the way how assets are managed, where spare parts play an important role. Repairable items, while units that can run an unlimited number of times between the asset (equipment) in which they are installed, the maintenance shop where they are submitted to maintenance activities (preventive or corrective) and the warehouse where they will wait for a demand, are very important elements once they represent a huge part of the inventory. This paper presents a methodology, initially developed in the aeronautics field to determine the optimum quantity of individual repairable items to exist in the warehouse to face their necessity. In the methodology it is taken into account the scheduled maintenance (hard time maintenance) as well as the unscheduled removals and the time of recovery in the maintenance shop. All these elements are gathered from maintenance historic data. The methodology also takes into account the risk by introducing the concept of Service Level. This work also presents a real case study, showing the applicability of the methodology presented and demonstrating its valuable contribution to the maintenance management decision making process.