5 Ways To 3D Print

5 Ways To 3D Print

Luke Howard

Jan 4th, 2019

WHAT ARE THE DIFFERENT TYPES OF 3D PRINTERS?

There are now over 10 different types of 3D printing processes available, but there are only 2 main processes for the general maker or small business owner: FDM printing, and SLA printing. Here I cover the top 5 methods of 3D printing and what they are used for. 

FDM (Fused Deposition Modeling) is the process of printing by depositing melted filament layer-by-layer in a predetermined path.

  • Common types of filament:  PLA, ABS, HIPS, nylon, PETG, TPU.
  • This is the most widely used, and affordable 3D printing technology.
  • A spool of thermoplastic filament is loaded into the extruder head that is on a 3-axis system, which heats the material to a specific temperature and deposits the material in a predetermined location on a heated print bed. The material cools and solidifies while on the print bed.
  • Each FDM printer takes a specific type of filament, so it is important to check with the manufacturer on materials that your particular printer can use.
  • It is also important to know that there are two main filament diameters 1.75mm and 3mm.

SLA (Stereolithography) is the process of printing by selectively curing a polymer resin layer-by-layer using an UV laser beam.

  • Common Material: liquid (thermoset) resin.
  • A resin tank is filled with liquid photopolymer and the build platform starts in the liquid. A UV laser cures the resin layer-by-layer on the predetermined path using a set of mirrors to direct the laser.
  • Although it is much more expensive than FDM printing, it is currently the most cost-effective way to achieve extremely accurate and smooth prints.
  • You can not melt an SLA print back to liquid resin because it uses thermoset plastics which burn once set, instead of melting.
  • The printing process does not fully cure the print. A post-curing process is needed to fully finish each print.

SLS (Selective Laser Sintering) is a selective lasering process that solidifies polymer powders and fuses them together layer-by-layer to create an object.

  • Common Material: thermoplastic polymers
  • Granular thermoplastic polymers fill a powder bin, where the polymers are heated to slightly below melting temperature, and then selectively fused together by a CO2 laser.
  • SLS prints are considered to allow more design freedom, higher accuracy, and more consistent mechanical parts than FDM or SLA.
  • Prints do not need support structures, because the uncured polymer powder acts as a support

MJ (Material Jetting): is the process of extruding drops of liquid photosensitive material that solidifies under UV light as it builds up layer-by-layer.

  • Common Material: Thermoset photopolymer resins
  • This is very similar to the 2D inkjet printing process, but this builds upon the layers.
  • It creates a very smooth finish while using a variety of materials and colors, which is useful for visual prototypes or tooling manufacturing
  • It is considered one of the most accurate printing processes with a dimensional accuracy of +/-0.1%, and warping is less prevalent than with other technologies

SLM (Selective Laser Melting) or DMLS (Direct Metal Laser Sintering): These processes are almost identical to each other and are part of the powder bed fusion 3D printing category (SLS).  A Laser selectively fuses metal powder particles, bonding them together to create an object layer-by-layer.

  • Common Material: Aluminum, stainless steel, titanium, cobalt chrome.  
  • The build chamber is filled with an inert gas (ie: Argon) to reduce oxidation and then heated to optimal temperature. A thin layer of metal is spread over the build plate before a laser fuses the powder on a predetermined path. This process is repeated for every layer as the build platform drops to allow new material to be added.
  • SLM uses a single type of metal powder that fuses at a specific temperature, while DMLS printing uses a variety of metal powders that have variable melting points.
  • Support structures in the design are needed for this powder bed fusion technology to reduce warping of the print.
  • Metal printed parts have greater strength, hardness, and flexibility than typical metal manufacturing techniques, but are more prone to fatigue.

Check out the Idea Foundry's 3D printing class and get started printing your own designs.