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.
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.
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.
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.