Additive manufacturing other materials

Additive manufacturing methods extends past polymers, also being available to metals and other materials using processes that are fairly analogous to those used for polymers. A list of these processes with brief descriptions is given below.

Metal

• Fused Deposition Modelling, FDM
• This is directly analogous to FDM for polymers, except using molten metal instead.
• Selective Laser Melting, SLM
• Type of powder bed fusion. Uses a laser to melt and bind metal in a powder bed. Analogous to SLS.
• Electron Beam Melting, EBM
• Type of powder bed fusion. Like SLS but uses an electron beam to melt the powder instead, and therefore, this process must be done in a vacuum.
• Laser Engineering Net Shape, LENS
• Type of direct energy deposition, DED. This can be seen as a mix between FDM and soldering. Metal wire is supplied to a build where is it then heated and melted by a laser, locally depositing metal onto the build surface
• Electron Beam Additive Manufacturing, EBAM
• Type of DED. Similar to LENS but an electron beam is used to heat the metal instead and therefore, this process must be done in a vacuum.
• Binder Jetting, BJ
• Binding agent added to metal powder, sticking the powder together. The bound powder is then later sintered once out of the powder bed. This is fairly similar to MJF without the use of IR radiation to immediately sinter the object.
• Nano Particle Jetting, NPJ
• Metal particles dissolved in a solvent liquid are applied to a print surface by nozzles. The object is heated immediately, evaporating the solvent leaving the metal particles. The object is then sintered later. The printing process is similar to MJ, but requires extra sintering and doesn’t use UV.

Other Materials

• Fused Deposition Modelling, FDM
• Same process as for metals and polymers. Material filament is melted and extruded through a nozzle.
• Paste Extrusion Modelling, PEM
• Very similar to FDM but used for materials that are a paste at room temperature, such as cement paste. The printing works in the same way except there is no heating element. Also, instead if filament, simply a paste supply is extruded through a nozzle onto the print surface.
• Binder Jetting, BJ
• Similar to metal BJ and polymer MJF. Binding agent droplets are applied layer by layer to a material powder bed, causing powder to stick. Generally used for sand or gypsum.
• Drop on demand, DOD
• DOD is a type of material jetting (MJ) and is similar to the MJ process for polymers. Hot material is jetted dropwise through nozzles, layer by layer onto the print surface. Material then solidifies on cooling. An example material used for this is wax.
• Laminated Object Manufacturing, LOM
• Nozzles apply an adhesive to the top of a build surface. A new layer of material is then laminated onto the previous layer, bound by the adhesive. The layer is then cut to give the correct cross section by a knife, laser or wire. The process is repeated to produce an object.

The table below shows a summary of processes that are similar to those used for polymers.

And the following table organises each method into broader AM methods.

Looking to the future, the number of materials available to additive manufacturing will continue to increase. One such material is organic matter (printing organic matter is sometimes known as bio printing), with ambitions of printing tissue to test drugs, and entire organs potentially for transplants.