Table 1.

Overview of processes for MMAM (adapted from [47]).

Categories	Technologies	Printed Ink	Power Source	Strengths/Downsides
Material Extrusion	Fused Deposition Modeling (FDM)	Thermoplastics, Ceramic slurries, Metal pastes	Thermal Energy	▪Inexpensive extrusion machine ▪Multi-material printing ▪Limited part resolution ▪Poor surface finish
	Contour Crafting
PBF	Selective Laser Sintering (SLS)	Polyamides/Polymer	High-powered Laser Beam	▪High accuracy and details ▪Fully dense parts ▪High specific strength and stiffness ▪Powder handling and recycling ▪Support and anchor structure ▪Fully dense parts ▪High specific strength and stiffness
	Direct Metal Laser Sintering (DMLS)	Atomized metal powder (17−4 PH stainless steel, cobalt chromium, titanium Ti6Al-4V), ceramic powder	Electron Beam
	Selective Laser Melting (SLM)
	Electron Beam Melting (EBM)
Vat Photopolymerization	Stereolithography (SLA)	Photopolymer, Ceramics (alumina, zirconia, PZT)	Ultraviolet Laser	▪High building speed ▪Good part resolution ▪Overcuring, scanned line shape. ▪High cost for supplies and materials
Material Jetting	Polyjet/Inkjet Printing	Photopolymer, Wax	Thermal Energy/Photocuring	▪Multi-material printing ▪High surface finish ▪Low-strength material
Binder Jetting	Indirect Inkjet Printing (Binder 3DP)	Polymer powder (Plaster, Resin), Ceramic powder, Metal powder	Thermal Energy	▪Full-color objects printing ▪Require infiltration during post-processing ▪Wide material selection ▪High porosities on finished parts
Sheet Lamination	Laminated Object Manufacturing (LOM)	Plastic Film, Metallic Sheet, Ceramic Tape	Laser Beam	▪High surface finish ▪Low material, machine, and process costs ▪Decubing issues
Directed Energy Deposition	Laser Engineered Net Shaping (LENS), Electronic Beam Welding (EBW)	Molten Metal Powder	Laser Beam	▪Repair of damaged/worn parts ▪Functionally graded material printing ▪Require a post-processing machine