What are the different 3D printing technologies?

The rather broad “3D printing” is a term that actually refers to a number of different processes. In this article, we break down the plethora of different technologies that encompass 3D printing so that you come away much more informed on what goes on behind the scenes of this new technology.

Vat Photopolymerisation

This is a method of 3D printing that includes a container filled with photopolymer resin, which is hardened by a UV light source.

Stereolithography (SLA)

This is a popular layering process that uses an ultraviolet laser and a vat of liquid curable polymer to create solid, physical objects. It was invented in 1986 by Charles Hull, who was one of the first people to achieve commercial success with this technology.

You can categorize an SLA printer into four main areas:

• Perforated platform
• Printer filled with liquid plastic
• UV laser
• Computer to control the platform and laser

During this process, the layers of plastic come into contact with the laser which hardens the material.

Digital Light Processing (DLP)

DLP uses light photosensitive polymers to print 3D objects. Although similar to SLA, it uses a different light source, like arc lamps, and is generally one of the quicker 3D printing methods.

Continuous Liquid Interface Production (CLIP)

This is one of the fastest 3D printing processes and it uses Vat Photopolymerisation that is developed by Carbon.

Material Jetting

In this 3D printing process, a small nozzle applies drops of material, building a platform by layering this material and using UV light to harden it.

Binder Jetting

You can use two materials with binder jetting: a powder base material and a liquid binder. The material is layered and bonded together by the liquid to form your 3D model. The leftover powder is cleaned at the end of this process and can be used again.

Material Extrusion

Fused Deposition Modeling (FDM)

FDM is a process that uses a plastic filament that is fed through an extrusion nozzle, with the ability to switch the flow on and off. The material is heated until it melts and can move both horizontally and vertically to build layers upon layers, which hardens as it leaves the nozzle.

Fused Filament Fabrication (FFF)

FFF is pretty much the same process, only FDM is Stratasys’ trademarked version of this technology.

Powder Bed Fusion

Multi Jet Fusion (MJF)

This is when a robotically controlled arm deposits powder in layers before another arm applies a binder agent using inkjets. These also release a detailing agent on top of the binder to create a smoother finish. At the end of the process, a blast of thermal energy causes the agents to react together and bond.

Selective Laser Sintering (SLS)

The process of SLS is where a powerful laser fuses particles of powder to form a three-dimensional object. It first scans the layers (cross-sections) on the powder bed’s surface then applies a new layer of material until the model is finished.

Direct Metal Laser Sintering (DMLS)

This is very similar to SLS, but it uses metal powder, and it’s developing into a laser melting process. You can reuse any leftover powder for your next project.

Sheet Lamination

Sheet lamination uses sheets of material, such as metal, paper, or a polymer of some sort, and welds them together using ultrasonic welding to build layers. It’s then CNC milled into the desired form.

In the case of paper sheets, adhesive glue is used to bond the layers and sharp blades cut it to shape.

Directed Energy Deposition

This is when 3D printing equipment is attached to a robotic arm with a nozzle attached. This deposits metal powder or wire and then a source of energy such as a laser, plasma arc, or electron beam, melts it to form a physical object.