Resin and filament are the two dominant technologies in 3D printing. So if you’re on the fence between buying a resin or filament 3D printer, we’ve got you covered. In this post, we’ll talk about the differences between resin and filament 3D printers and talk about the advantages and disadvantages of both.
What is FDM(filament) 3D printing?
Fused Deposition Modeling or FDM 3D printing is the most common type of 3D printing technology in use today. It is also known as FFF, or Fused Filament Fabrication.
The key term to understand here is deposition. In FDM 3D printers, plastic filament is melted and forced through a nozzle that deposits the plastic on a surface, layer by layer.
In essence, each layer is deposited on the printer bed, and as the next layer is deposited, it fuses with the previous layer.
Layer by layer, the model forms on the 3D printer bed.
FDM or FFF printers are very common because the printers themselves come in a wide range of budgets starting from less than $300 all the way up to thousands of dollars. Even the budget 3D printers do a great job of printing most models, and the filament is cheap.
What is resin 3D printing?
Resin 3D printing is called SLA printing, which stands for Stereolithography. Resin 3D printers are slowly becoming more and more common and there are some budget options out there on the market.
SLA or resin 3D printers use a liquid resin as the medium to fabricate the model. The liquid resin is light-sensitive, which means it hardens when exposed to certain kinds of light.
SLA printers use a laser beam to “draw” the model in the resin. Anything the light touches will harden.
Another form of resin 3D printing is called DLP, which stands for Digital Light Processing. Unlike SLA, where the entire model is “drawn” by the laser beam, in DLP 3D printers, each layer of the model is projected onto the build surface and each layer solidifies as it is exposed to light.
In resin printers, the entire print bed is submerged in a vat of resin and it rises up out of the vat.
SLA vs FDM Differences
Variety of materials and colors
FDM printers are compatible with a much wider variety of materials than resin or SLA printers.
FDM printers can use many different kinds of filament:
- TPU and other flexible filaments
Nearly all FDM 3D printers are compatible with these filaments, perhaps with the exception of nylon, which requires an all metal hot end to maintain the high temperature required to melt it. Still, even if your 3D printer did not come with an all-metal hot end in the stock configuration, you could easily upgrade it for a relatively small cost.
Each of these filaments are also available in a really wide variety of colors. PLA is by far the most common, and you can find a huge palette of colors to choose from. ABS is also available in many different colors.
PETG and TPU are generally available in fewer colors, but it really depends on the manufacturer.
Additionally, with the exception of a few 3D printers, any brand of filament is compatible with any printer as long as the filament diameter matches the hot end. The two diameters available are 1.75mm and 2.85mm.
Resin printers are quite limited with the type of material they can work with
Resin printers are much more finicky with the type of resin they can use, and in many cases, you’ll have to use the resin specified by the manufacturer of the 3D printer as it will not be compatible with other types of resins.
Resins are available in a limited variety of colors, and most resins are just the typical hard plastic.
Formlabs is a manufacturer that does offer different resins such as flexible and extra-tough.
Cost: Is resin cheaper than filament?
Filament is far cheaper than resin. A 1 kg spool of filament will set you back between $15 to $20, whereas a 500gm bottle of resin costs around the same.
Another cost to consider is the other parts of your 3D printer that undergo wear and tear. In filament printers, these are the nozzle and print bed.
Nozzles are quite durable and unless you end up with a monster clog that you’re unable to clean, you may not need to replace your nozzle for a long time.
The print bed may get damaged from scratches incurred when removing prints. In this case, you don’t need to replace the entire bed: just replacing the top surface is sufficient. As a tip, unless you have a magnetic bed, don’t print directly on the stock bed. Use a sticker that you can easily replace if needed.
In resin printers, the other consumable is the protective film on the print bed. The film gets smudged over time, and you’ll need to replace it to make sure the light can get through easily.
Is resin printing easier than FDM?
FDM printers are very straightforward and once the model is printed, there is comparatively little post-processing required. Resin prints require a lot more post-processing for every single model.
When your FDM model finishes printing, it’s fairly easy to remove from the print bed. In some cases, you can just pull the model off the bed. Other times, you may need to use a paint scraper to get between the bed and the bottom of the model and pry it off.
Still, the model comes off with minimal effort.
If you don’t need any extra finishing and you’re satisfied with the model as is, that’s pretty much it. Just remove it from the bed and you’re good to go.
You may also wish to sand the model to smooth the surface a little, and if you print with ABS, you can use acetone to really smooth the print.
In case your model uses supports or rafts, you will need to remove the supports or rafts once the print is complete. Supports can be easily broken off with your fingers or pliers, but rafts require a bit more effort to remove.
If you did use supports or rafts, you may need to sand the bottom of the model to get the finish you are looking for.
For really strong PLA prints, you can consider annealing them in an oven.
However, the bottom line is that FDM printers can get away with very little post-processing.
Resin prints are much harder to remove from the print bed. There’s a lot of extra resin on the print bed that you’ll have to clean up after each print, too. The issue of extra filament does not arise with FDM printers.
There’s also some post-processing that you must do after each resin print:
- A completed resin print will still be covered in a sticky film of leftover resin that you need to wash off with a bath of isopropyl alcohol. You should wear rubber gloves when handling these parts as you don’t want your skin to come in contact with too much resin or alcohol
- For maximum strength, the resin part needs to be cured with UV light, so you’ll need to pick up an extra UV curing station for best results.
Finishing and smoothness
FDM printers generally produce parts that have visible layer lines.
Since FDM printers lay down filament layer by layer, the resolution of the print is the thickness of each individual layer. You can print at really small resolutions if your printer supports it, and in this case, the layer lines will hardly be visible.
However, you’ll find yourself using somewhere around a 0.2mm layer height for most prints, and in these models, you’ll clearly be able to see the layer lines.
FDM printers are also not very good for printing highly detailed parts like miniatures. Some features of the miniature model may not print correctly, even if you use a very small layer height.
Resin printers are able to produce very detailed models
Since resin printers use light, they are able to produce highly detailed models even at very small scales. That’s what makes them a super choice for printing very small parts that require lots of accuracy and detail.
The last main point of difference between filament and resin printers is safety. While it’s not fair to say one is objectively safer or more dangerous than the other, both have their own considerations that you must be aware of.
Filament 3D printers tend to release microparticles in the air which can cause issues. It’s always best to use any 3D printer in a very well-ventilated area. PLA is generally the least harmful filament to print, but ABS releases toxic fumes as it melts, so you must print in a ventilated area, use a fume hood, or both.
Resin is also no child’s toy. It is an irritant and should be handled with care. That’s why you should always wear hand and eye protection when handling resin. When it comes time to remove the print, you will get resin on your hands.
Also, since resin is UV sensitive, you can get a chemical burn if resin is on your skin and gets exposed to UV light(sunlight).
Resin vs PLA strength
Resin and PLA are both similar in terms of strength. Both are fairly rigid, but will degrade with prolonged exposure to the sun. However, filaments like ABS and PETG are much stronger than resin and if you need strength and UV resistance, those two filaments are the ones to use.
Resin vs Filament for miniatures
For miniatures and prints that require fine details, resin is the way to go. Resin printers are amazing for finely detailed, tiny prints. It may end up costing a little more due to the higher cost of the resin, but the finish will blow FDM prints out of the water.
Conclusion: should I get a resin or filament 3D printer?
If you need accuracy and detail and cost is not a limiting factor, you should get a resin 3D printer. If you don’t need so much accuracy, wish to print a wide variety of materials, and are on a budget, stick to a filament 3D printer.
To summarize, resin printers are good for:
- Highly detailed models like miniatures
- Moulds for mass-production
- Prints where strength is not critical
Filament printers are good for:
- Printing many different materials
- Printing many models, fast (rapid prototyping)
- Hobby printing and educational purposes