Filament-based 3D printers spent a long time at the developmental forefront for hobbyists, but resin-based printers have absolutely done a lot of catching up, and so have the resins they use. It used to be broadly true that resin prints looked great but were brittle, but that’s really not the case anymore.
A bigger variety of resins and properties are available to hobbyists than ever before, so if that’s what’s been keeping you away, it’s maybe time for another look. There are tough resins, there are stiff resins, there are heat-resistant resins, and more. Some make casting easy, and some are even flexible. If your part or application needs a particular property, there is probably a resin for it out there.
What is Available?
Resins can be purchased direct from printer manufacturers (like Elegoo, Anycubic, Phrozen 3D, Prusa, Peopoly, and more) and some manufacturers (like Siraya Tech or Monocure 3D) do not make printers, but specialize in resins that work with them.
Resins generally come in a few broad categories, and I’ll briefly discuss each.
Tough / Durable
Tough resins tend to be durable in the sense that they offer some impact resistance and wear resistance, and do not shatter when they break. “ABS-like” is a term commonly used by manufacturers for resins that aim for these properties, but it’s not an exclusive one. There are others that fit the bill as well.
People who print miniatures for tabletop games are one of the communities getting a load of value from resin printing, and those folks really value detail and durability because tabletop miniatures get handled a lot, and frequently have small protruding bits. Resins like Siraya Tech Tenacious, and Phrozen Aqua-Grey 4K/8K are great choices, yielding high detail and durability even on small pieces.
Some enthusiasts even indulge in a kind of resin alchemy, and merrily experiment with mixing resins together (such as adding 10% flexible resin into other formulations) to get just the right results. In fact, Monocure 3D’s Flex100 resin is specifically aimed at that sort of thing.
Flexible
Some resins are specifically formulated to bend or elongate under stress, and these typically have “flex” in the name. However, how much a particular resin flexes (or doesn’t) isn’t always clear from pictures.
To get a better idea of what a flex resin’s print will be like, look for a Shore number accompanied with a scale designation: 00, A, or D. The number is a measure of the hardness of the material; higher numbers are harder. A handy scale with references to everyday objects makes Shore hardness easy to interpret.
Heat Resistant
Resins that can take a lot of heat without softening, deforming, or otherwise degrading are branded specifically as being heat resistant, and “High Temp” is often part of the name.
Prints made with these resins are hard, but are also brittle and glassy compared to others. Their heat resistance and dimensional stability means they make excellent molds for things like thermoforming or injection molding, however.
Castable
Aimed mainly at jewelry applications, these resins are formulated to burn away cleanly when used in casting, without leaving any ash or residue behind in the process. They come in a few slightly different formulations, depending on the manufacturer, but their purpose is the same.
When Not to Mix and Match
Most of the resins and manufacturers mentioned above are, broadly speaking, all in the same ballpark. The printers that use them are masked SLA printers that cure resin by shining a UV backlight through an LCD located at the bottom of the build tank. Using one manufacturer’s resin in another’s printer is therefore mainly a matter of calibrating exposure times. (There are resources out there trying to centralize these settings, as well.)
However, there are different types of resin printer, and their resins are not interchangeable. Formlabs is manufacturer of professional and semi-professional printers and resins, and their printers use a UV laser to cure resin instead of a UV backlight and LCD screen. They have a fantastic variety of resins for various purposes, but their resins are specifically formulated for their printers. Formlabs resins will not work properly in masked SLA printers, and resins intended for masked SLA printers will not work properly in a Formlabs printer.
There’s Plenty of Choice Nowadays
Resin printing is very accessible and there are now quite a few options for different resins with different properties, so whatever your needs are, there is probably a resin to match it. Just remember to use proper protective equipment, and follow reasonable safety precautions when working with resin. Wear gloves, clean spills promptly, and please don’t pour anything related to printing down a household drain.
Has resin printing solved a problem you had? Perhaps you have a favorite resin, or mixture of resins for a specific purpose? Let us know all about it in the comments.
Is there some specific reason why Formlabs resins are incompatible by MSLA? Viscosity? Curing wavelength?
I’ve used Formalbs resins successfully in an Elegoo Saturn, but the exposure times are WILD, like 45 seconds.
mSLA resins have 2-6X the Photoinitiator of traditional laser SLA resins. We buy Industrial SLA resins and give them an Irgacure bump and save a ton, but that has more to do with buying drums instead of liters
As random noise said, the resins for SLA machines (that use laser point to cure) have much less photoinitiator in it, so the curing doesn’t happen so fast (and release too much heat). On the other hand, the resins for LCD printers needs to much more reactive as there is not as much activation energy.
You can use SLA resins in MSLA, but with very high exposure times – on mono screens usually 30-90 seconds. You cannot use MSLA resin in an SLA printer as you will probably damage it. The curing reaction will happen very fast and it will release too much heat that can damage the bottom of the resin tank.
The main hurdles (besides price) is the post-processing and the cleanup. Post processing (UV, bath) has been mainly automated, with the user just needing to transition the model. The cleanup part is the key one. Just having to deal with a thick liquid makes them less friendly compared to their FDM brothers.
Slowly, innovation has been chipping away at these hurdles.
True, VOCs and ultrafine particles are bad enough printing with FDM machines (but can be sucked away / filtered) but having to handle huge basins of isopropyl alcohol just isn’t that fun in living rooms. I use that stuff for cleaning my printbeds and let the rag gas out outside… It quickly fills the room with that “hospital smell”.
I use Simple Green rather than IPA. I get clean prints and no lingering stink in the room.
There are now resins that are water soluble in their uncured state.
I built a hood system for my Formlabs and it has made it possible to print in my home office. In the long run I am going to move to a warehouse because I’m ramping up to sell a product but for now I have been prototyping and doing small test batches in the house. The hood is definitely helpful.
I built a hood system for my Formlabs and it has made it possible to print in my home office. In the long run I am going to move to a warehouse because I’m ramping up to sell a product but for now I have been prototyping and doing small test batches in the house. The hood is definitely helpful.
Ever since I saw BCN3D’s VLM process, I’ve started researching into resin printing as I believe a solution exists for a wash+cure feature built into the printer itself. I’m also looking into filtration methods for the cleaning fluid to further reduce the amount of hazardous waste and a sliding LCD so that a smaller and cheaper-to-replace (and higher resolution) screen can be used to print large parts at the expense of print time.
Anyone have a good link for a big list of resins and their properties. (I know there is one for filament, they even printed swatches.) I have been in the market for something but being able to place my finger on it (with all of the available options) has been difficult.
I use the table at: https://4dfiltration.com/resources/resin-properties.html
This is exactly the type of thing I was hunting for. New resin is on the way, gracias Senor.
And that is a large part of the problem with these resins, we all sort of know instinctively what ABS, PET, PLA are like and how they handle forces, and they are so well charecterised you can really do the structural engineering maths too.
Still some other flaws like UV/Chemical stability and oil/water absorption not mentioned here too (are very rarely any details on them in the data sheets) and the wildly varied content of the datasheets are inconvenient, but it is nice that resin now is really reaching the viable stage for many things beyond the high detail pretty bits.
Exactly that. I tried 4 resins, all of them softened in water so I went back to fdm. It’s too hard to know what you’re getting as only “positive” traits are listed.
I’m thinking I will end up doing both, but FDM for me has many more positives than just well defined material properties, its also just plain and simple a thermoplastic – so much simpler to recycle the old and failed prints and usually cheaper to buy.
But there is no getting away from the resin detail level. Only the laser sintered powder printers can come close to it, with their own limitations, though again the material properties are very much more quantified, and detail levels are very good.
It is like a Form Labs press release…. After that company bricked our machine with a firmware update, all I can say is better options are out there.
“Formlabs resins will not work properly in masked SLA printers, and resins intended for masked SLA printers will not work properly in a Formlabs printer.”
I thought it was just because the Formlabs resin costs 5x as much and comes in DRM’d ink cartridges?
On the Formlabs printer, does using 3rd party resin void the warranty?
Though, I do know that some resins don’t play well the PDMS vat.
On one hand, both types of resin are activated by UV. But the laser in Formlabs printers can dump a lot more energy into the resin compared to resins intended for printers with a UV backlight behind an LCD screen.
3rd party resins don’t void a Formlabs warranty, there’s a printer setting specifically for running ??? resins (it’s called “Open Mode”.) I’ve also used 3rd party resins intended to be compatible with Formlabs printers by just pouring them into an old cartridge for convenience.
I guess whether the cartridges count as DRM’d depends on what that term means to you. The cartridges identify the resin to the machine so the printer can apply the right settings (and throw an error if you try to print something with a mismatch; like you send a job for resin X but you installed resin Y) and it’ll warn about when the cartridge is expected to get empty/low, that’s about it. It won’t refuse to print if it thinks the cartridge “should” be empty, or anything like that.
I’ve been using and FDM 3D Printer for several years now, and I use it all the time. I even modified it to print hit temp filaments and enclosed it in a soft fabric housing for filaments that need a warmer enclosure. I bought a Resin printer several months ago as I figured it would be just as nice and useful as my FDM printer, but I ended up returning it after only a few days. My family just couldn’t handle the smells of the Resin and Isopropyl constantly filling up the whole house. FDM is just so much more home use friendly. I have my FDM printer in my bedroom and it never causes any issues with bad smells. Resin printing at home is really only feasible if you have a detached garage or shed you can keep everything in.
Just build a cheaper enclosure near a window and pump fumes out of the window. I did that for my FDM printer for the more noxious filaments.
Mimeographs had a strong smell but eventually technology matured and that was dealt with.
Never used one, but copies made with (by teachers) had a distinctive smell.
There are resins that cleanup with water so there’s no alcohol smell. I’d bet they’re not caustic or not as caustic when uncured as the ones that are alcohol soluble.
What’s with the waste water? Can you put it down the drain? Is it toxic for aquatic life? I guess (haven’t really looked it up) that stuff needs to be disposed of properly…
Please don’t dump it down the drain, it’s toxic with the uncured resin dissolved in it. After it settles one can leave the solution out in the sun for a couple days and it will cure the dissolved resin which can be filtered out and put in the trash, and the water will evaporate or can be reused to wash again. The manufacturer should have notes on disposal too.