Table 1.

Layer bonding mechanisms of different beamless metal AM techniques.

Material Melting	Bulk Sintering	Electrochemical	Thermo/Mechanical
Liquid metal printing, Wire and arc AM (WAAM), Shape Deposition Manufacturing (SDM)	Binder jetting (BJ), Nanoparticles inkjet printing, Material extrusion, 3D screen printing (3DSP), Aerosol jet process, Selective inhibition sintering (SIS)	Electrochemical fabrication (EFAB), FluidFM 3DP	Ultrasonic AM (UAM), Cold spray AM (CSAM), Friction stir AM (FSAM), Additive friction stir deposition (AFSD)