Additive manufacturing (AM) is revolutionizing manufacturing in conventional industries and will undoubtedly enable applications that have not yet been conceived.  AM is the collective name used to describe high energy, layer-by-layer processes. Subsets of AM include cold spray, stereolithographic (SLA) 3D printing, powder bed fusion (e.g. selective laser melting - SLM), fused deposition modeling (FDM), binder jetting, and direct energy deposition. Many of these processes rely on interacting with a metal powder including cold spray, metal printing (both SLM and binder jet printing), and SLA of ceramic filled resins.

 

SLM is a relatively mature additive manufacturing technology where a bed of metallic powder is melted by a laser or electron beam that moves along a predetermined path to build a metal part in a layer by layer process. Cold spray is less mature and involves depositing oxide-free metal powder in a supersonic gas stream to an existing part or substrate while avoiding the generation of residual stresses. Cold spray is most often used to repair specialized metal components that are cost-prohibitive to replace. SLA of ceramic filled resins remain relatively uncharted.

 

Additive approaches are finding their place in the general toolbox of industrial manufacturing. Still, there remain materials and applications that are dominated by casting or subtractive technologies which focus on bulk materials in which interfaces play a nominal role in the ultimate part. Instead, with the complexity and layer-by-layer approach of additive, interfaces abound! Continued success of powder-based additive manufacturing depends to a great extent on addressing the following grand standing challenge: Can the additional interfaces created with the additive process be transformed from a weakness into a strength?