Fused Deposition Modeling (FDM)
This is the most frequently used method in desktop 3D printing. Thermoplastic filament is heated and extruded through an extrusion head which then passes the molten plastic in X and Y coordinates, while the build table lowers the object layer in the Z direction.
SLA is the earliest form of 3D printing technology, invented in 1983. This 3D printer creates smooth surfaced objects with extreme detail, and is increasingly popular in inudstries such as jewellery and cosmetic dentistry.
Digital Light Processing (DLP)
Equal to SLA, DLP uses liquid photopolymers, which are cured by applying light to it using a special projector. Tilting tiny mirrors back and forth, the reflecting light creates a bright pixel, or a dark pixel. This is commonly used in movie projectors, mobile phones and for 3D printing. The ability to print layers with this printer is instantaneous.
Selective Laser Sintering (SLS)
SLS 3D printers use powdered materials in the building process. A laser is used to selectively sinter a layer of granules, which combines the materials to create a solid structure, and then left to cool in the machine before being removed. SLS is most likely used for product development and rapid prototypes in many commercial industries, as well as limited-run manufacturing of end-use parts.
SLM (Selective Laser Melting)
Some see SLM as a subcategory of the SLS printer type, as SLM uses a high-powdered laser beam to fully melt metallic powders into solid 3D parts. Stainless steel, aluminium, titanium and cobalt chrome are the most common used materials for this printing process, which are utilised mostly in aerospace or medial orthopedics industry.
Electron Beam Melting (EBM)
This technique uses a computer-controlled electron beam under high vacuum to fully melt the metallic powder at high temperatures up to 1000 degrees. This 3D printer uses metals such as pure titanium, Inconel718 and Inconel625 to fabricate aerospcae parts and medical implants, and is one of the slower printing processes and very expensive.
Laminated Object Manufacturing (LOM)
LOM fuses adhesive-coated paper, plastic or metal laminates, under heat and pressure and shapes by cutting with a computer operated laser or knife. Commonly followed by machining or drilling, the 3D object is created layer-by-layer, and once excess is taken away, the object is sanded or sealed with paint.
Binder Jetting (BJ)
Also known as 'powder bed printing' or 'inkjet 3D printing', this additive manufacturing process uses two materials - a powder based material and a bonding agent. The agent acts as an adhesive between powder layers, and the binder is usually extruded in liquid form from a printhead, similar to a regular inkjet 2D printer.
Material Jetting (MJ)/Wax Casting
This technique has been used by jewelers for centuries, and is now also used for experiments involving casts. Molten wax is deposited onto an aluminium build platform in layers using several nozzles which pass over the build area. Once heated, the material jets onto the build plate and then solidifies. A different wax with a lower melting point is then placed below overhangs in the product, acting as a support, and once finished is put in a heated bath that melts away the support.