Purpose-For more than ten years, the value of additive manufacturing (AM) for after-sales service logistics has been propagated. Today, however, only few applications are observed in practice. In this paper, possible reasons for this discrepancy are discussed and a method is developed to simplify the identification of economically valuable and technologically feasible business cases. Design/methodology/approach-The approach is based on the Analytic Hierarchy Process (AHP) and relies on spare part information that is easily retrievable from the company databases. This has two advantages: first, the approach can be customized towards specific company characteristics, and second, a very large number of spare parts may be assessed simultaneously. A field study is discussed in order to demonstrate and validate the approach in practice. Furthermore, sensitivity analyses are performed to evaluate the robustness of the method. Findings-Results provide evidence that the method allows a valid prioritization of a large spare part assortment. Also, sensitivity analyses clarify the robustness of the approach and illustrate the flexibility of applying the method in practice. More than 1000 positive business cases of AM for after-sales service logistics have been identified based on the method. Originality/value-The developed method enables companies to rank spare parts according to their potential value when produced with AM. As a result, companies can evaluate the most promising spare parts first. This increases the effectiveness and efficiency of identifying business cases and thus may support the adoption of AM in after-sales service supply chains.

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Consolidation of parts is the redesign of an assembled component with fewer, but therefore more complex parts. While complex parts are often difficult to produce with conventional manufacturing (CM) technologies, the high degree of design freedom of additive manufacturing (AM) facilitates consolidation. Typically, consolidation with AM is chosen because of its functional befits such as weight reductions. Consequences for asset maintenance, however, are not that well understood. For example, the spare part management may profit from potentially shorter resupply lead times of AM, but may suffer from more expensive consolidated parts having to be stocked in anticipation of random failures. Together with a different price and failure rate of AM components, this complicates the decision whether AM should be used to consolidate a spare part. In this paper, we analyze the total costs of consolidation with AM, including logistics, manufacturing and repair costs. Our results suggest that consolidation with AM often leads to higher total costs. This finding mainly stems from loss of flexibility. For example, the repair of a component by replacing the defective sub-component only is no longer possible. Furthermore, short resupply lead times for the consolidated spare part turn out to be less beneficial than perceived and therefore relativize the benefit of consolidation with AM. Overall, these findings stress the necessity to adopt a total costs perspective when judging the effects of AM on spare parts management. Otherwise, consolidation may lead to unforeseen effects which may render its application debatable, even despite substantial functionality improvements.

The low-volume spare parts business is often identified as a potential beneficiary of additive manufacturing (AM) technologies. Currently, high AM unit costs or low AM part reliabilities deem the application of AM economical inferior to conventional manufacturing (CM) methods in most cases. In this paper, we investigate the potential to overcome these deficiencies by combining AM and CM methods. For that purpose, we develop an approach that is tailored toward the unique characteristics of dual sourcing with two production methods. Opposed to the traditional dual sourcing literature, we consider the different failure behavior of parts produced by AM and CM methods. Using numerical experiments and a case study in the aviation industry, we explore under which conditions dual sourcing with AM performs best. Single sourcing with AM methods typically leads to higher purchasing and maintenance costs while single sourcing with CM methods increases backorder and holding costs. Savings of more than 30% compared to the best single sourcing option are possible even if the reliability or unit costs of a part sourced with AM are three times worse than for a CM part. In conclusion, dual sourcing methods may play an important role to exploit the benefits of AM methods while avoiding its drawbacks in the low-volume spare parts business.

Additive Manufacturing (AM) is rapidly gaining interest as a highly innovative manufacturing technology, having many advantages over more conventional manufacturing methods. These advantages include the ability to produce very complex structures that are relatively easily customized to specific user requirements. The fact that AM services become affordable for small companies or even for consumers offers possibilities for decentralized manufacturing, downstream in the supply chain. In addition, AM allows for high degrees of flexibility, both in product design and manufacturing, as a result of using smart CAD systems that may be based on accurate scanning technologies. The ability to work with low setup times and costs, and to largely eliminate work in progress inventories while maintaining a high degree of supply chain responsiveness makes AM a promising alternative for low-volume, high-value items. In this chapter, we outline the basics of AM technologies, after which we discuss at a more advanced level its impact on the supply chain. Next, we turn to spare parts delivery in after-sales service supply chains; these slow moving parts are often mentioned as ideal candidates for AM. In a state-of-the-art report, we provide a methodology for the identification of spare parts that may appear promising candidates for the application of AM. We conclude with a field study conducted at a service provider in the aerospace industry. 28.1. Additive Manufacturing (basics) Additive Manufacturing (AM) is a technology that enables the production of complex geometries and near-net shape components. Its name stems from the fact that it builds a component, part or product from raw materials layer by layer (additively). Conventional machining methods such as cutting, milling, drilling or lathing, remove material and are therefore classified as subtractive manufacturing. Although only recently known to the broader public, the first AM technology was already commercialized in the late 1980's, when it was used as a technique for rapid prototyping, called stereolithography. In this technology, a vat with a vertically moving platform is filled with a photocurable liquid polymer. With the platform in upper position, a laser focuses an ultraviolet beam on the upper surface layer, curing that part of the photopolymer to create a solid body. Next, the platform is lowered a bit and the cured polymer is covered with another layer of liquid polymer, after which the sequence is repeated (Kalpakjian, 1992). By varying the shape of each new polymer layer, complex geometries can be built up with stereolithography. 28.1.1. Basic technologies, characteristics and fields of application Today, there exists quite a variety of AM technologies, of which the most important ones are Selective Laser Sintering (SLS) and Selective Laser Melting (SLM), Electronic Beam Melting (EBM), Digital Light Processing (DLP) and Fused Deposition Modeling (FDM). For a detailed exposé of these different technologies we refer to Gibson et al. (2015); here it suffices to say ...