How Safe Are 3D Printing Resins?

Material extrusion like fused deposition modeling (FDM) is the most popular polymer 3D printing technology, but resins are resonating among consumers. Resin-based techniques, like stereolithography (SLA), used to only appear in dental labs, engineering departments, and manufacturing facilities thanks to their higher cost. Now that these machines are more affordable, more casual users are considering SLA, raising questions about their safety.

Unlike FDM, resin printers use photosensitive liquids to print, hardening these materials with UV light. While these liquid resins can create highly detailed prints, they may present more potential health risks than filaments. This toxicity may scare some users away, but resin printing can be potentially safe if you follow the right steps.

What Potential Risks Do Resins Pose?

The word “toxic” can be frightening, but by the definitions created by the Occupational Safety and Health Administration, any substance that’s suspected of causing injury or illness under some conditions is “toxic.” Under that definition, a lot of everyday materials are potentially toxic, including some perfumes and mattress foams. So, what are the specific hazards with printing resins?

The leading risk with photopolymer resins is that they can irritate your skin if they come into contact with it. In some cases, resin contact on bare skin can lead to burns and blisters, possibly requiring medical attention. If these materials touch your eyes, they could cause permanent damage.

Many resins are sensitizers, which means prolonged exposure can cause you to develop a mild allergic reaction. The chemicals that make up most resins are irritants, which cause dermatitis, a skin inflammation from your body rejecting foreign material. Your skin also absorbs these chemicals quickly, so if you get enough on yourself, it can lead to more severe reactions.

Another health concern with 3D printing resins is air contamination. Resin gives off fumes, potentially compromising your indoor air quality (IQA). Poor IQA can result in fatigue and headaches or more severe reactions like breathing problems. These reactions come from volatile organic compounds (VOCs) and other small particles, which elicit an inflammatory response from your respiratory system, leading to swelling or increased sensitivity.

Long-term effects from working with resins are rare but not unheard of. If you work around these fumes for extended periods, it could cause lasting issues with your respiratory system. Some of the VOCs resins emit are suspected carcinogens, so there’s a chance they could cause cancer after prolonged exposure. Similarly, continued physical contact can lead to allergies.

Manufacturer Standards and Guidelines

On the positive side, most resins you can get on the market won’t pose a substantial risk. The companies that make these materials must meet government standards and may comply with additional regulations like ISO 9001, too. These guidelines ensure the chemicals these companies produce are minimally harmful. However, some chemicals like asphalt fumes and synthetic mineral fibers used in fiberglass, are still used prevalently and over half a million workers have been exposed.

Image courtesy of Vikash Mishra on Slideshare.

Resin manufacturers also typically provide a material safety data sheet (MSDS) that outlines any possible health and safety concerns, such as corneal burns from overexposure of the eyes or nausea and vomiting from ingestion. If your resin didn’t come with one, you can ask the manufacturer and they’ll give it to you. These documents provide the resources you need to stay safe while using these materials.

You should always look for allergy information in an MSDS, since some people have allergic reactions to touching resins or breathing in the fumes. As a result, some resins could be more dangerous to some users than others. If you don’t know if you have any material allergies, act as if you do, and handle everything with caution.

Steps to Ensure Resin Printing Safety

Several authorities have conducted studies on 3D resin printing safety. These have all found that long-term emissions from printing are mostly negligible, although if you don’t follow the proper precaution, there are risks. Since studies have found traces of hazardous materials in resin printing environments, you should follow safety guidelines.

3D printing resins may not be as dangerous as they first seem, but you should still take precautions with them. Above all else, remember to avoid direct contact with the liquid resin with any part of your body. You should always wear protective goggles and nitrile or latex gloves to ensure nothing gets in your eyes or on your hands.

You should also make sure your workspace is well-ventilated so you don’t breathe in the fumes. Ventilation is a critical consideration with any 3D printer, but especially for resin printers. Working under a ventilation hood is the best option, but if that’s not practical or affordable, you can work near an open window with a fan.

Before you even open a container of resin, read the manufacturer’s MSDS. If there are any special considerations for that particular material, you’ll find them there. Finally, don’t dispose of leftover resin by pouring it down the drain, which could harm the environment. Either absorb it with a manufacturer-recommended material or cure it with UV light until it hardens.

Resin Printing Is Safe If You Follow the Proper Precautions

When you know what risks resins present, you’ll know how to take care around them. While 3D printing resins are toxic, you don’t have to worry about them if you follow these safety procedures. With the right precautions, there’s no reason to avoid resin printing.