2013 Volume 21 Issue 4 Pages 263-277
When a new model of a machine is introduced, fewer units of the old model are shipped but spare parts must still be supplied to customers continuing to use the old model. However, many companies, especially those not involved in direct sales, struggle to supply parts and hold a suitable inventory because of the difficulty of determining the product lifetime and the number of working machines (NWM). Accordingly, this paper aims to use data on shipments of machines and parts to analyze NWM, order quantity of spare parts, and inventory in the supply chain. From the analysis, a method for estimating NWM and the order quantity of spare parts is proposed, and a policy for holding inventory is discussed. A classification scheme based on trends in spare part orders and an inventory policy for each classification are devised. Finally, the method is validated against actual data on small developing machines.
