How Does Resin 3D Printing Work?

November 8, 2022 - Ellie Poverly

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When most people think of additive manufacturing or 3D printing, they picture large spools of plastic filament and a print head melting it and placing it one layer at a time. At the end of a print cycle, you have a three-dimensional item ready to use or display. While this is one form of 3D printing, it isn’t the only one that’s commercially available. Imagine submitting a sliced image to a 3D printer and seeing it rise, one layer at a time, from a pool of colored liquid. It sounds magical, but that’s the basis of resin 3D printing. How does resin 3D printing work?

How Does Resin 3D Printing Work?

3D printing is also known as additive manufacturing unless you’re talking about resin printing. You’ll hear this form of printing referred to as vat polymerization or stereolithography (SLA), but for ease of understanding, we’re just going to refer to it as resin printing. 

Resin printing takes the printing bed and flips it upside down, submerging it in a vat of resin. Until the resin is exposed to a UV laser, it remains in a liquid state. The laser acts as the print head, drawing each design layer onto the print bed. As the laser touches the resin, it hardens into the finished product. This process continues until the print is complete and the finished product is ready to pull off the print bed. 

Besides the actual printing process, most of the steps leading up to pressing the print button are the same. A digital 3D design still needs to be sliced and sent to the printer so it can create one later at a time. Unfortunately, resin 3D printers tend to be a bit slower than filament printers because the resin needs time to cure. 

Benefits of 3D Resin Printing 

Even if it is a little slower, 3D resin printing still has many benefits. They’re better than filament printers when creating incredibly complex projects. Resin printing will be the better option if you’re printing miniatures for tabletop gaming or small components for a delicate project. Also, unlike filament printing, there are no print lines to sand away on resin-printed products. 

The only major downside of resin printers is that they tend to have a smaller build plate, so if you’re trying to build a large set of cosplay armor or weapons, you’ll have to slice your project into smaller sections and stock up on resin while you wait for each piece to print. 

Can 3D Printing Resin Spoil?

Unlike 3D printing filament, you can’t leave an open vat of resin sitting on your desktop for weeks or months and expect it to continue functioning correctly. If properly stored, 3D printing resin has a shelf life of around 12 months. However, you may find some brands that claim their products last anywhere from 18-24 months. Leaving the containers open or leaving them in the vat where it’s exposed to sunlight, heat or other potential contaminants could ruin an entire vat in a matter of days or weeks. 

The cooler you keep your resin, the longer it will last. A good rule of thumb is to keep your resin out of direct sunlight and away from intense heat. Keep an eye on the resin. If it changes color, it’s a good sign that it has spoiled and needs to be replaced. 

Printing Just About Anything

3D printing is quickly gaining momentum as one of the most valuable and versatile tools to emerge in recent decades. It has grown in popularity with consumers and commercial engineers alike, giving users the power to print just about anything. 3D resin printing is just the next step in this technological evolution. 

Revolutionized is reader-supported. When you buy through links on our site, we may earn an affiliate commision. Learn more here.


Ellie Poverly

Ellie Poverly is a science writer specializing in astronomy and environmental science and is the Associate Editor of Revolutionized. Ellie's love of science stems from reading Richard Dawkins books and her favorite science magazine as a child, where she fell in love with the experiments included in each edition

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