On the suitability of insourced Additive Manufacturing for spare parts management

Abstract

Additive Manufacturing (AM) has recently emerged as a promising technique in spare parts manufacturing. Unlike conventional manufacturing (CM) techniques, AM can lead to a reduction in inventory levels, particularly when insourced, through manufacturing spare parts on demand. However, due to the high production costs, the economic benefits of manufacturing spare parts through AM are unclear to managers and practitioners. Recent studies aimed at assisting in this decision have two main limitations: (i) they assume that AM spare parts typically have higher failure rates than CM parts: and (ii) they do not consider the AM machinery investment costs and parts are assumed to be externally supplied. We have developed a model that overcomes these limitations, first by assessing the failure rates of AM spare parts through an interdisciplinary approach rather than making arbitrary assumptions, which enables a comparison with the failure rates through CM reported in the literature. Second, we considered that the manufacturing of AM spare parts can be insourced and thus the investment costs for AM printers are also included, while the manufacturing of CM spare parts is considered to be outsourced. The model was tested with unconstrained and constrained stock systems, and clearly demonstrates the advantages of an insourced 3D printer for on-demand printing under constrained stock systems. Neither is AM preferable under an unconstrained system, due to the high costs of purchasing the printer and of production.