When it comes to 3D printing safety, most people think of printer fires. However, 3D printers also produce particulate matter and volatile organic compounds (VOCs). So, what exactly is the big problem with 3D printing and particulate matter, or VOCs?
We will introduce the main issues of 3D printing emissions from a safety perspective and, more importantly, some misunderstandings. Finally, we’ll give you some solutions so you can ensure that you and those near your 3D printer are safe while printing.
When it comes to the safety of 3D printing, there will be some misunderstandings in terms of emissions. These misunderstandings can be divided into four major statements:
1. Fiction: 3D printing PLA is 100% safe without a ventilation system.
It turns out that PLA produces particles that are more toxic than ABS. However, at the same temperature, PLA does not produce as many particles as ABS, which leads to confusion about the printing safety of PLA in terms of VOCs and ultra-fine particles.
In other words, higher printing temperatures tend to release more ultra-fine particles and VOCs than lower temperatures. Since PLA prints at a lower temperature than ABS, it doesn’t release as many toxins overall.
2. Fiction: If it doesn’t smell bad, it won’t be harmful.
This is simply not true, because many trace VOCs and ultra-fine particles in 3D printing do not have a strong smell, and the harmfulness of the smell is not directly related to the harmfulness. In other words, if you can smell the smoke produced by the 3D printer, then you are undoubtedly inhaling VOCs and ultra-fine particles, which may affect your health in the future.
3. Fiction: 3D printers must be ventilated outdoors; otherwise, they cannot be filtered.
In fact, most 3D printers are not ventilated to the outside because, when they are, heat is lost from the cavity, increasing the chance of deformation and other undesirable effects.
4. Fiction: HEPA filters will not filter out nanoparticles produced by 3D printers.
This is also incorrect. HEPA filters can and do filter out nanoparticles produced by 3D printers, although they are rated for particles larger than ultrafine particles.
1. Emission issues
Emissions from 3D printing are generally divided into two categories: particulate matter emissions and VOC emissions. Below, we’ll discuss each in detail and then explore their dangers.
particulates
First, let’s define particles. Due to the way FDM and SLA 3D printers cure plastic, there are always ultrafine particles produced into the air that can be inhaled during the printing process. However, since the size of the particles is so small, only 100 nanometers or less, it is impossible to see these “ultrafine particles.”
Therefore, it is the size of these particles that makes them dangerous. Because they are easily inhaled, long-term exposure can cause damage to the lungs or other tissues.
VOCs
As opposed to particulate matter, VOCs refer to the “smoke” you may smell when a 3D printer prints with certain filaments, such as ABS.
If you’ve ever smelled burning plastic, dry paint, or even campfire smoke, you’ve likely inhaled some kind of VOC. We’re not saying campfire smoke is inherently dangerous, however, breathing it in day after day can lead to a variety of illnesses, depending on the chemicals inhaled.
Does the type of 3D printer matter?
Unfortunately, the two most common 3D printers, FDM and SLA, produce particles and VOCs under normal printing settings. There are several articles, like this one from Georgia Tech and the EPA, that directly address these issues and what types of things can affect emissions.
2. Harmful effects
The big question is: Why are inhaling VOCs and particulates potentially harmful? When it comes to VOCs, the answer is straightforward. If you’ve ever seen the warning on the side of an aerosol can that says “Do Not Inhale,” there are a bunch of warnings about the health hazards associated with inhalation, and here’s why.
Specifically, according to HealthLinkBC, inhaling certain VOCs can cause a variety of short-term health problems, such as “eye, nose, and throat irritation, shortness of breath, headaches, fatigue, nausea, dizziness, and skin problems.” Long-term health problems can include permanent organ damage and even some cancers.
In contrast, ultrafine particles work a little differently than VOCs because the particles themselves are not necessarily harmful chemicals themselves. The dangers of ultrafine particles come more from their size and their ability to penetrate deep into the lungs, among other similar issues. There is evidence that ultrafine particles can even have long-term cardiovascular effects, as well as various health risks.
3. How big is the relative risk?
It is important to note that many processes in daily life produce ultrafine particles and VOCs. Common cooking activities, such as cooking on a gas stove, produce similar amounts of ultrafine particles as 3D printing. However, extra care should be taken as 3D printers typically run much longer than traditional gas stoves and therefore tend to produce more particles overall.
4. Solution
Hope we didn’t scare you too much. And, have no fear, there are three main ways to reduce VOCs and particulate emissions during the 3D printing process.
Place your printer in a closed environment. The biggest way to reduce particulate matter and VOCs is to prevent them from leaving the work area around the printer in the first place. Many people accomplish this by building “fences” to slow the spread of toxins, essentially trapping them within the printed area.
Of course, due to the particle size and nature of VOCs, this won’t make you completely safe unless your enclosure is perfectly sealed, as VOCs and particles can leak out over time. However, in many cases, it will slow it down enough for your existing ventilation system to keep the particle density outside the enclosure fairly low.
Use filters to capture particulates and volatile organic compounds (VOCs)
The second way to reduce particulate matter and VOCs is to use an air filter with a housing so that the particles and VOCs are absorbed by the filter. See below for how to choose the right filter type, as it depends on the type of emissions you want to eliminate (particulates vs. VOCs). You have a variety of options, from relatively DIY to expensive options.
Vent smoke outdoors
A third way to reduce particulate matter and VOCs is to simply vent the print area to the outdoors. This option is listed last because it has a significant drawback. By venting the print area to the outdoors, you will cool the print area. This will make printing with filaments like ABS difficult, as without a heated build plate and chamber, prints tend to warp easily.
5. What type of filter is needed?
What are the options for 3D printing filters? Basically, in order to filter out both VOCs and particulate matter, you need the following two types of filters.
Note that this applies to both FDM and SLA 3D printers, although the relative amounts of particles and VOCs differ between the two methods. SLA often needs to remove more VOCs, while FDM printers often need to remove more ultra-fine particles.
1. HEPA filter or high-grade MERV filter (MERV 17 or higher). These types of filters can remove ultrafine particles.
2. Activated carbon filter. This type of filter removes VOCs.
Of course, activated carbon filters and HEPA (or high MERV) filters come in many shapes and sizes. Nonetheless, they are a relatively simple solution for removing particulate matter from the air. Under normal working conditions, HEPA air purifiers can remove ultrafine particles in the air with very high efficiency, reducing them by 99.97%.
Interestingly, although there is a misconception that these filters only work up to 0.3-micron particles, in fact, smaller particles are captured by the filter in higher quantities due to Brownian motion.
So if you want to keep the heat in a 3D printed enclosure but still be safe and remove particles and VOCs, you can simply place an air purifier inside the 3D printed enclosure. Air purifiers should use both HEPA and activated carbon filters to ensure that both types of emissions are significantly reduced.
Here are several options for filtering these emissions
Wall-mounted unit: Alveo3D has created a 3D printed filter unit that filters out VOCs and ultra-fine particles. Each filter is made from HEPA H13 and activated carbon and includes a 120-mm high-pressure fan to move air through the filter.
Air Purifier: Another option is to purchase an air purifier and use it inside your 3D printed enclosure to filter VOCs and particles.
3D Printed Purifier: Our last option looks pretty silly, but you can make one out of a disposable P100 filter and some 3D printed parts, although you’ll probably need an extra fan to make it work. Designers believe that this type of filter does nothing to reduce ultrafine particles, but as we mentioned before, this is not the case due to the Brownian motion theory of filtration.
It’s important to note that where you place your filter affects its effectiveness. We recommend positioning the filter according to the manufacturer’s instructions, which will vary depending on the type of filter and the amount of air passing through it.
7. What can I do during this time?
If you’re looking for a quick solution but haven’t decided yet what type of filtration system you want to use, there are a few simple ways you can reduce the impact of your emissions.
First, if there are other filters in the room, the temporary filter’s MERV rating can reduce particulate matter in the air.
Alternatively, if the temperature is not too hot or too cold, you can print near an open window, lowering overall particles and VOCs. Ideally, a fan should be installed near the printer to blow particles and VOCs outside and minimize circulation indoors.
