FDM vs. SLA: Understanding these 3D Printing Technologies

FDM vs SLA: How do these 3D printing technologies compare? What is their difference? Read on to find out.

If you are already familiar with 3D printers, you probably know about FDM 3D printers.  But what does FDM actually mean? Are there any alternatives to it?

In this guide, we’ll look at two of the most popular 3D printing technologies; FDM and SLA.

What does SLA mean? What is the printing process used? What are the differences between FDM and SLA?

Read this guide to help you get started.

sla fdm comparison

FDM vs SLA: What is the Difference?

FDM

FDM stands for Fused Deposition Modeling.

With FDM technology, plastic filament is melted, extruded and stacked layer by layer through a pressure nozzle. It doesn’t matter whether the layers are printed by shutting down the heating bed or by powering up the hotend.

The standard thermoplastics are mostly PLA, ABS, HIPS or PETG.

FDM 3D printers are mainly popular with 3D printing hobbyists. These printers are cheaper, reliable and easier to use than SLA Printers

SLA

SLA stands for stereolithography.

This was the first 3D printing technology to be widely adapted for professional area. In the stereolithography process, liquid resin is hardened at certain points using a laser or LEDs to create model shapes.   This process is also called photopolymerization.

Generally, SLA printers are more expensive and a little complicated to use than their FDM counterparts. However, things have been changing over the past few years. Today, there are dozens of SLA 3D printers that are easier to use and cheaper.

As a result, while SLA printing process was initially confined in professional use, today hobbysists can also get cheap and easy-to-use SLA printers on the market.

Now that we know the two technologies, which one is better? Which technology is faster and more precise? What about cost-effectiveness?

Continue reading.

Benefits of FDM 3D Printing

FDM 3D printers are fed with filament, such as PLA or ABS. The filaments typically have a diameter of 1.75 mm or 3 mm. However, the 1.75 mm diameter filament is becoming accepted as standard.

The filament is fed through a stepper to the hotend and heated there. Depending on the material, the hotend is between 190 and 260 degrees.

fdm pressure structure

The hot filament is pushed on and pressed through the nozzle, which may be of different diameters.  Most diamter measure 0.4 mm. Generally, the larger the diameter, the coarser the printed image.

It is important that the liquid filament is cooled again immediately after the nozzle so that it does not flow.

You can compare the FDM printing principle to how a  hot glue gun works. When one level has been completely covered, the hotend is raised by 0.x millimeters and the next level is filled. After, usually, hundreds of levels, the 3D printing is finished.

Here are some highlights of FDM printing:

  • Filament costs: About $20 for 1kg (see picks on Amazon)
  • 3D printer costs: Cheap FDM 3D printers start at around $100 (see recommendations on Amazon)
  • Easy to maintain and modding
  • generally low operating volume
  • Print speed depends on the type
  • Scales better in size / purchase price
  • Operating volume (3-4 steppers make “noise”)
  • high temperatures are required. This also means high power consumption
  • Accuracy / resolution is “average”

Since an FDM printer is “just a better hot glue gun”, rebuilding, adding or tuning them is relatively easy. Aside from electronics, the printers have simple operating mechanics. The most important thing you will need to tune in an FDM printer is the steppers to reduce vibrations.

If you are looking for a good quality, budget FDM printer, get the Anet A8. This inexpensive produce quite high-quality prints.

Anet A8 3D Printer Review

 

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Read our Anet A8 3D printer review here .

Best FDM 3D Printers

Over the past years, we have tested dozens of FDM 3D printers. These three are our favorites for beginners:

Anycubic I3 Mega

Anycubic i3 Mega

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Features: metal frame, 2 Z-axes, touchscreen, and print area of 210 x 210 x 205 mm

Creality3D CR-10

Creality3D CR-10

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3D printer with a very large community and installation space of 300 x 300 x 400 mm

QIDI Technology 3D Printer

QIDI Technology 3D Printer

SEE ON AMAZON

 

>Benefits of SLA 3D Printing

Stereolithography, while seeming more complex, is actually the older technology. The technology was already in use in the early 1980s and is still used more in the professional sector.

In the past, liquid resin was usually hardened with a laser. However, there are more and more low-cost solutions with powerful UV LEDs.

sla pressure build up

The graphic above shows the printing process well.

The Z-axis is immersed in the resin bath and the mirror directs the laser beam to the area to be cured. The Z-axis slowly moves up over time and dips the print object into the resin again and again.

Highlights of SLA 3D printing include:

    • The resolution is, depending on the type, very, very precise
    • Low operating volume
    • Low heat and power consumption
    • Often less space is required for the entire device
    • Resin costs: About $50 for for 500g  (see prices on Amazon)
    • Not easy to repair, i.e. have no “DIY kits”
    • Multiple accessories (e.g. UV hardener) are required
    • Undetectable danger (laser!)
    • Have a small print area

Formlabs is certainly one of the pioneers in low-cost SLA 3D printing for beginners. Watch the video below about the printer:

Which 3D Technology Should You Use?

Currently, FDM 3D printing is still clearly ahead in the hobby area. There are hundreds of different 3D printing models you can experiment with.

Moreover the filament is cheaper than resin.

sla 3d print

What about SLA 3D printers?
Well, to begin, resin is still relatively expensive. In addition, the printing areas are relatively small.
However, if you want to print precise 3D prints on a small scale, you will need an SLA 3D printer.

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