Considerations for 3D Printers: The Difference Between FDM and SLA 3D Printers


Three dimensional printing machines, FDM and SLA 3D printers.

This is an excellent overview of the basic considerations for 3D printers for beginners, or even advanced users.

You’ve probably heard of FDM and SLA 3D printer models, but what is the difference between them?

Both of these technologies can be used to print plastic parts. But that’s where the similarities end. They both have their own advantages and disadvantages.

In this article we’ll take a look at how each technology works, which one is better for certain applications, and when it makes sense to use one over the other.

Companies have been using FDM, or SLA, printers for years because they are cost-effective and reliable.

The 3D printing and additive manufacturing market has experienced rapid change in recent years. While still being used by hobbyists, highly capable desktop machines have developed into essential tools for businesses for prototyping and even for production.

Fused deposition modeling (FDM) and stereolithography (SLA) are the two most popular types of 3D print systems on the market. Both 3D printing technologies have been adapted and refined for the desktop, making them more affordable, easier to use, and more capable.

In this comprehensive buyer’s guide, we take a closer look at FDM and SLA 3D printing machines, and how they compare in terms of print quality, materials, applications, workflow, speed, costs, and more, to help you decide which technique is ideal for your business.

In this article we’ll take a look at how each technology works, which one is better for certain applications, and when it makes sense to use one over the other.

Designing for manufacturability has been a crucial part of 3D design for many years. To start, let’s understand the differences in the technologies:

FDM or “Fused Deposition Modeling” is the most common form of 3D printing to date. FDM 3D printers work by using a plastic or metal wire (filament) that is supplied to a heated extrusion nozzle which both melts and places the filament on the build plate.

SLA / SL or “Stereolithography”, also known as stereolithography apparatus, optical fabrication, photo-solidification, or resin printing, is a form of 3D printing technology using resin to create more detailed objects with finer surfaces in a layer by layer fashion. SLA uses photochemical processes by which light causes chemical monomers and oligomers to cross-link together to form polymers.

When you’re ready to start producing your finished products, you’ll need to figure out what material (or combination of materials) you’ll be using. Optimizing your design, and selecting the correct material(s) and 3D printer is important to allow for the desired precision and control.

3D printers that use FDM can 3D print with a variety of materials, but they’re limited to only plastics like PLA and ABS.

On the other hand 3D printers that utilize SLA technology can 3d print in resin which opens up an entire new world of possibilities when it comes to printing parts. For example there are many different options, including:

  • Tough resin (ABS-like)
  • Durable resin (PP-like)
  • Heat resistant resin
  • Rubber-like resin (flexible)
  • Ceramic filled resin (Rigid)

From an application standpoint consider these points:

  • Standard resins are used for general prototyping
  • Engineering resins have specific mechanical & thermal properties
  • Dental & medical resins have bio-compatibility certifications
  • Castable resins have zero ash-content after burnout

It’s also important to note that printers utilizing SLA printing technology can 3D print in a variety of colors, while FDM printers are typically limited to one color.

In some cases it’s possible to use more than one material at once on an FDM 3D printer for example you could combine PLA filament with wood filled filaments which would give the 3d printed object a wooden appearance.

When it comes to your printing applications, SLA printers are typically used for objects with fine details such as jewelry and figurines, or rigid parts that require high strength or heat resistance (e.g., industrial machinery).

If speed is a concern, SLA printers can 3D print objects at a slightly faster rate than printers using FDM printer technology.

FDM 3d printers are typically used for prototyping, while SLA 3D printing is more suited to short-run production applications.

If cost is a concern, FDM 3D printers are the most cost-effective way to get into 3D printing. FDM 3D printers are available at reasonable prices on the market. SLA 3D printers are generally higher in cost.

Once you’ve invested in software, developed models, and invested in a printer, to start printing with an FDM 3D printer is as simple as sending a .stl file to the printer and watching it work its magic. For SLA 3Ds, you need to prepare your model for 3D printing first by creating supports manually or automatically (which can be time consuming).

Once the 3D printed parts come out of FDM printer they will often look like they were dipped in plastic. 3D prints, especially using FDM, will commonly require post processing steps such as sanding and polishing to smooth the surface of 3D printouts, as such, it’s not possible for these 3Ds to achieve the high levels of detail that SLA 3Ds can.

In summary, there are lots of factors that should be considered when deciding between SLA or FDM 3D printers which depend on the 3D printing application and the quality, cost and desired output required.

3D printing is a complex topic and there are lots of 3d printer technologies available, but hopefully this article has given you some “3D” insight into the differences between FDM 3Ds and SLA 3Ds.

To learn more about purchasing a printer read more here:

What To Know Before Buying 3D Printer – Guide (2021)

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