Additive or conventional manufacturing for the management of spare parts inventories? The impact of qualification testing

Additive manufacturing (AM) is a promising technology for spare parts management given its ability to produce spare parts on-demand, reducing lead times and inventories. This potential has attracted interest from spare parts managers, who are contemplating switching from Conventional Manufacturing (CM) to AM for spare parts production. To support decision-making, researchers have developed cost-based models to evaluate production, backordering, and holding costs of AM and CM technologies, but have overlooked qualification costs. Qualification testing, necessary for all spare parts, involves significant costs (especially for critical parts). To fill this gap, this work incorporates, for the first time, qualification costs into a cost model, helping spare parts managers in identifying when switching from CM to AM is cost-effective, and quantifying the impact of qualification costs on AM convenience. Additionally, as new AM qualification procedures are emerging, we investigate their impact on AM's cost-effectiveness, highlighting future scenarios for spare parts inventory management.