Dottorato in INGEGNERIA AERONAUTICA E SPAZIALE

Titolo della tesi: Additive manufacturing based Supply Chain. Extreme part consolidation and procedural aspects for the production of aerospace spare parts.

Additive Manufacturing (AM) embraces a set of innovative manufacturing technologies which can differ greatly one from the other, but share the common principle of building objects in a layer-by-layer fashion. This aspect separates AM from the conventional manufacturing technologies and opens the path to new possibilities for designers. Acknowledged conventional manufacturing constraints limiting the shape complexity of the components are overcome with AM which thus allows, among others, a complexity-for-free fabrication. AM has thus attracted a lot of attention, both from the industry and the academy. The aerospace is the most prolific sector along with the automotive, bioengineering and medical ones for the evident advantages that AM can deliver in these fields. For these sectors, AM is already a consolidated reality. AM plays a role not only as a fabrication means, as it is expected to have a major role in the rising Fourth Industrial Revolution, or Industry 4.0. This is the attempt, shared by many Superpowers, to increase the efficiency and the sustainability of the new Industry by interconnecting humans and machines. The target is shifted from a mass production to a mass customization aiming at providing real added-value goods to the consumers. The complexity-for-free feature of AM along with its predisposition for low-scale productions fits this context perfectly. Simultaneously, AM-base supply chain has been the topic of many researches. Based on AM capabilities to produce on-demand, tailor-made components, the shared view envisions smaller, higher number of de-localized fabrication processes operated in order to answer specific customer’s needs. The benefits for the aerospace sectors are several, mainly due to the elimination of warehousing, minimization of inventory and eventual spare parts obsolescences. This work shows how AM can lead part-consolidation design guidelines to the extreme. This has a relevant impact on AM-base supply chains, as those assembly-dedicated facilities can be eliminated. In fact, not only the part consolidation can be obtained with AM, i.e. the reduction of the number of the parts, but also the integration of mechanism and locking/unlocking features allowing to get rid of fasteners. With the satellite market shifting its focus on constellations made up of hundreds of small satellites rather than single big satellites, this can lead to a cost-saving, due to the acknowledged role played by assembly operations in driving costs. Moreover, this work makes AM implementation for the production of spare parts a step closer. A dedicated workflow leading to a standard component to an AMed counterpart is proposed. This is built based on the indications of the existing literature. This is applied to a real test case - a support for a back-up analogical compass aircraft - and all the phases of the process are discussed in detail with particular attention to the re-engineering phase. The importance to consider AM-related aspects for no-critical components in terms of performance is manifest, as they allow to drive the design toward the reduction in wasted material and the speed-up of the manufacturing process. Considering the high cost of AM material and the generally low throughout speed, these aspects are crucial for an efficient implementation of AM in the supply chains.