3D printing doesn’t quite work like normal printing – while when it comes to ink on paper, just about any machine that uses, well, paper and ink, will do, 3D printing is a lot more specific. Not every printer, or even every type of printer is suitable for every filament type or project – you’ll need to do your research before picking one to make sure you get the right type for your needs.
Here is a summary of some of the most common types of 3D printers you can find. It’s not a comprehensive list, but these are the ones a budding 3D printing enthusiast needs to know about!
SLA or Stereolithography was the very first kind of 3D printing ever. Created in 1986 by Chuck Hall, it uses a printing technique that is called Vat Polymerisation – it uses photopolymer gum that is exposed to a light source. This type of printer is ideal for smooth surfaces, and high levels of detail on printed projects.
It’s not particularly one for beginners and has a lot of uses in medicine, where it is used to print anatomical models as well as microfluidics. The printer uses multiple mirrors arranged to point a laser pillar across the gum used as a filament, so that it can form the different layers in the forming zone.
Accuracy and speed are key, and 3D print projects are built from the base up. In addition to the mentioned uses in medicine, this printing technique is also useful in aviation and the auto industry. Printers of this type include ProJets and Vipers.
Specific laser sintering or SLS softens nylon-powders into a solid plastic build. Materials used are thermoplastics, which means the results are tough, suitable for snap-fits and high impact uses. The technique used is called power bed fusion. A thermoplastic will be heated until just before it liquefies and then layered onto the forming stage. A laser is used to sinter the powder that has been stacked into a solid, hard layer – and when a cross-segment is complete, the stage drops by the height of that layer, more powder is added, and the laser once again sinters it to a solid.
Excess powder that is added but not sintered serves as a sort of supporting material that will eventually fall away. Support structures aren’t needed because of this. The main advantage of SLS is that it creates great mechanical properties, with the drawback of longer lead times than other types of printers. Examples include the Sinterit Lisa, Formlabs Fuse 1 and Sharebot SnowWhite 2.
Fused Deposition Modeling and Fused Filament Fabrication are similar types of printer. They expel a plastic fibre layer by layer onto the forming stage. This way, complete models can be created relatively quickly and efficiently. Created surfaces tend to be anything but smooth and the resulting models are also usually not too strong. In other words, actual usage of printed parts can be fairly limited. Despite this, this type of printer is a great choice for beginners as it is experiment-friendly and fairly easy to use.
That said, this type of printer can be one of the more affordable ones for printers on a budget. A spool of filament is run into the printer and then pushed through a heated spout. The most common materials used are PLA, ABS and PET, but some others work too, depending on the spout used.
The printer’s head moves along set axes, and dispense the liquefied plastic layer by layer. When a layer is complete, the next layer is launched until the object is complete. Some of the best uses for this technique are fixtures and casings, but FFF and FDM are also suitable for all sorts of small vanity print projects.
Printer models include the Snapmaker and Ultimaker, as well as plenty of others. Given how widespread this type of printer is now, there are lots of different models in all price ranges.
Digital Light Processing is somewhat similar to SLA printing. It prints faster and uncovers layers at the same time rather than doing it in cross-parts with the use of a laser. SLA and DLP have similar usage purposes and are infusion shape type models. Unlike FFF, surfaces are smooth and therefore projects can find applications in things like dental applications.
On the flipside, DLP prints are somewhat weak. They aren’t normally useful for mechanical parts or anything that requires particular stability. As for the differences between SLA and DLP – where the former uses a laser to draw rounded shapes, DLP uses a screen to project square voxels of a certain minimum size in order to create the shapes that are being printed.
Printers of this type include the Micromake L2, SprintRay Moonray and Anycubic Photon S.
Multi Jet Fusion printers assembles parts from nylon powder. Rather than a laser (like in SLS printing), an inkjet cluster is used to apply the heat to melt the powder. The outcome is more stable and predictable mechanical properties, as well as better surface results.
The faster fabrication times this technique offers also leads to lower creation costs overall. The print head jets hundreds of small droplets of photopolymer that are cured and solidified later in UV light. When a layer is cured, the next layer is applied until the object is complete.
This technique does need a helper material that is taken out in post-handling. While that can present some difficulties, MJF is one of the only techniques that allows printers to produce multiple objects in a single line without sacrificing any of the build speed. It can also produce things using different materials and in full tone. This means that when arranged optimally, MJF can mass-produce small identical parts significantly faster than any other printer type. Printers of this type include the HP Jet Fusion series.
PolyJet printers produce smooth and accurate parts suitable for a variety of things. They offer a microscopic layer resolution and can produce both thin walls and complex elements since they can work with the widest variety of materials out of any 3D printer (provided they are equipped with the right nozzle/bed, of course). PolyJet prints can be used to create fixtures, molds, and various manufacturing tools.
There is a variety of printer models specifically for use in dental work – for dental labs and dental printing. The fast and high-quality prints that result from this technology make it a great choice for that sort of medical usage. These printers work by using several jetting heads – they deposit a layer of build material by sliding along an axis. Each head contributes different amounts in different spots in order to create whatever the shape of that layer may be. The most common setups of these printers feature a multi-nozzle inkjet-style print head.
The distributed materials are flashed and hardened by a UV layer before the printer moves along – the platform drops a layer, and the next layer is added. The raw materials and filaments are stored not on spools but rather in cartridges that are hooked up to the nozzles, not unlike a regular inkjet printer. Printers of this type include the Connex 3 series, the Objet30 and the J5 DentaJet.
DMLS printers have one primary application – printing metal-based things. Using metal-based additives, DMLS are the standard machines for any sort of 3D prints that involve MF filaments. While some other printers are capable of handling the material as well, DMLS ones are particularly good at creating uniform parts with similar qualities to things that were cast out of ‘normal’ metal.
DMLS is short for Direct Metal Laser Sintering, and that’s exactly how it works – it uses a high-powered laser to melt powdered layers of metal/plastic mixes before hardening them again to create the project. It works similar to how one might weld or solder with a very fine and precise laser, however it is faster and much more accurate than human hands could hope to be.
These printers are fairly complicated to use and require/use some unconventional elements (such as the usually argon gas-filled build chamber) and are therefore really not suitable for beginners at all – especially considering their painfully high prices. That said, they can work with various alloys and metals, including steel, titanium, nickel, cobalt, and copper. DMLS printer models include the EOS M 290 and the FormUp 350.
Electron Beam Melting is a type of powder bed fusion printing. It uses an electron beam rather than the typical laser to fuse particles and build the part. It creates incredibly stable and resistant structures by fusing metal to metal. Currently, this technology is only used and manufactured by one company – GE Additive.
Compared to other printers that use lasers as a heat source, EBM printers use an electron gun to extract electrons from for example a tungsten steel filament in a vacuum. They are then sped up and projected onto the metallic powder that is deposited for each layer.
When the project is printed, excess powders are removed with a blowgun. Since the whole process happens under a vacuum, parts and powder don’t oxidize while they are being used – and when the print is done, a good amount of the unused powder can be used directly. This is different from most other printing techniques, and significantly reduces the cost of printing, as materials can get quite expensive, especially when it comes to metal filaments.
Compared to laser beam printers, electron beam ones have the advantage of speed, but suffer a little in regards to precision and maximum production part size. Since the beam is wider than a laser, some things that are possible with a laser can’t be done in an EBM printer. Given the limited number of available printer models, there is also a limitation on part sizes – the manufacturing volume of a laser printer can easily be double that of a comparable EBM model.