Review of additive manufacturing technologies and applications in the aerospace industry

Additive manufacturing (AM) is transforming all segments of the aerospace industry, including commercial and military aircraft, space applications, as well as missiles systems. Such transformation is due to the unique ability of AM to produce parts with complex designs, reduce manufacturing costs (material waste, assembly due to part consolidation, and the need for tools and fixtures), and fabricate parts with premium materials with small production runs and short turnaround times. AM allows the realization of advanced part designs that provide additional space, multifunctional parts, multimaterial parts, part consolidation, and parts that are difficult to machine. The capability of AM to fabricate freeform designs makes it very suitable for the aerospace industry. To date, aerospace companies, such as Boeing, have installed tens of thousands AM parts (including 200 unique nonmetallic part references) on 16 commercial and military aircraft. It has also started the production of titanium AM parts that will allow savings of up to three million USD per aircraft in the near future. GE Aviation is using metal AM to manufacture thousands of fuel nozzles annually for its new LEAP engine. Similarly, Airbus is utilizing metal AM brackets and bleed pipes on its aircraft. It is currently collaborating with Arconic on the production of large-scale AM airframe components and expects to produce 30 t of AM metal parts by December 2018. The main applications of AM in the aerospace industry are rapid prototyping, rapid tooling, and repair, as well as direct digital manufacturing (DDM) of parts made of metal, plastic, ceramic, and composite materials. Currently, the fastest growing application is DDM (final part manufacturing). For metal parts, the main AM technologies in aerospace applications are directed energy deposition and powder bed fusion. For nonmetallic parts, the dominant AM technologies are vat photopolymerization, material jetting, and material extrusion. This chapter reviews the applications, benefits, and opportunities of AM for the aerospace industry, describes the relevant AM technologies, and discusses the current challenges and potential applications.