Can 3D Printing Cause Cancer? How To Use It Correctly? How Do Schools Choose 3D Printers?

China produces millions of consumer grade 3D printers every year and sells them to all parts of the world. A relatively part of them are used by users at home or in the office. Not long ago, the Antarctic Bear office had a new LCD light curing 3D printer. A model had been printed all night. The next day, when the office door was opened, a sharp smell of photosensitive resin came to my face. I had to clean the resin materials immediately and open the window for ventilation. I stayed outside for several minutes before returning to the office.

Today I want to talk about a serious question: how about the security of 3D printing?

When the air is filled with the wonderful smell of plastic melting, it just proves that the 3D printer is working hard at this time. But you may have seen that after the media disclosed that 3D printing was poisonous last year, they must be worried: "How much harm will these gases emitted by 3D printers do to human beings? Will it do harm to human health if you put the 3D printer in the bedroom and let it operate overnight? Will it affect the health of employees if you put the 3D printer in the office?

No matter where you plan to put the 3D printer indoors, you can learn how to choose and purchase the 3D printer from the perspective of science, research and practice through this article, as well as how to ensure air quality and safety in the use process.

What is the composition of these gases? Can it cause cancer?

The research shows that all 3D printers (FDM/FFF 3D printers are mainly analyzed in this paper, and UV curing and other technologies will be tracked and investigated later) will produce emissions when printing. Some of them are harmless but have odor, which are generated after the materials are heated, and others may be harmful to health. To judge whether these emissions are safe, it is necessary to pay special attention to the content of particulate matter (PM) and volatile organic compounds (VOCs) released by the printer.

Particulate matter (PM) and volatile organic compounds (VOCs) emitted by 3D printer (photo source: US EPA)

Inhalable particulate matter (PM): Generally, particles inhaled by people will accumulate in the lungs. If the content of particles is too high, it will cause respiratory diseases, such as asthma. In addition to 3D printers, these particles also appear in daily life, such as car exhaust, mountain fire burning, etc. PM2.5 is also a pollution index that we often pay attention to in daily life.

Volatile organic compounds (VOC): Usually, when decorating or buying a car, special attention will be paid to VOC, such as formaldehyde. Last year, as the relevant news reports said, some VOCs caused by 3D printers are carcinogenic, but the toxicity of these emissions has not been thoroughly studied, and the investigation is still in progress.

Although detailed investigation is still in progress, the harm of FDM emissions to human body depends on the operating environment and exposure time. In 2021, a study found that human exposure to emissions for an hour or less will not affect health. But those who stay around the printer every week and work for more than 40 hours may suffer from respiratory diseases. The gray area between 1 hour and 40 hours needs to be further verified by experiments.

△ All printers in the laboratory of Kettering University in Michigan were sealed in the 3DPrintClean filter box (photo source: Kettering University)

Although the data and conclusions about children are also under study, we need to pay more attention to schools, especially the 3D printing innovation laboratory in schools. A research report on the emission of 3D printers by the US Environmental Protection Agency (EPA) shows that children may be particularly vulnerable to the impact of 3D printer emissions. The study found that compared with adults, children aged 9 to 18 years old inhaled particles emitted by 3D printing, the surface area of their lungs covered by particles was larger. EPA believes that this may be related to children's greater curiosity and preference for close contact with print heads, and children's respiratory tract is still in the development stage and vulnerable to infection.

△ 3 Doodler, a foreign manufacturer, specially developed a 3D printing pen for children to reduce PM by reducing the melting point

Therefore, this article will take you through the current research results one by one to help you, especially educators, understand how to protect yourself when using 3D printers indoors, and how to consider if you plan to purchase 3D printers.

How to reduce possible health risks when using 3D printers

△ The 3D printing studio of Alto University, Finland, has collected a large number of data about 3D printers and the impact of their emissions on health and air quality. This paper quotes the data of the school in part.

1. Use low emission materials (such as PLA) and select original or brand wire

First, the biggest factor affecting FDM emissions is consumables. According to a number of studies conducted by the U.S. Environmental Protection Agency (EPA) and other departments, the type of consumables has a crucial impact on emissions, depending on the raw materials used by manufacturers and the intermediate synthesis process - different consumables contain different toughening, coloring and other additives, which are affected differently by hot melting. The US Food and Drug Administration (FDA) also said recently, "With the increasingly wide application of 3D printing technology, it is necessary to investigate the impact of consumable additives on human health. In the future, FDA will continue to investigate the characteristics of other additives and the volatile organic compounds and particulate matter involved, and issue relevant standards."

At present, most FDA studies focus on the analysis of the three most common consumables - ABS, PLA and nylon. ABS is generally classified as a high emission material. In addition to generating a large amount of PM and VOCs at the beginning of ABS use, the emissions during the whole printing process are very stable. As mentioned above, since the VOCs emitted will quickly combine with the particulates and become integrated, the main emissions continuously generated in the future are basically particulates. The emission of PLA and nylon materials is less than that of ABS. These materials will also produce a large number of particles at the beginning of use, but will not continue to discharge. Therefore, we generally call these materials low emission materials.

At the same time, they also noticed that the emissions of PLA would be affected by the brands of consumables. The quality of consumables of different brands was uneven, and the emissions of some PLA were even close to the emissions of ABS. Rodney Weber, a researcher at Georgia Institute of Technology, discovered this as early as 2017 after conducting an experiment on the emission of consumables. He urged users to be cautious about buying cheap unlicensed consumables. He said, "We found that the aerosol concentration generated during printing will be higher when using cheap consumables than those produced or recommended by the original factory or well-known brand manufacturers. Although PLA is made of biodegradable materials such as corn starch, we and the Aerosol Association have found that some particles and compounds emitted by PLA are even more toxic than ABS. But since PLA only produces these harmful substances at the beginning of printing As time goes by, the toxicity of ABS consumable emissions will gradually exceed that of PLA consumable emissions.

△ Regarding the emission of 3D printing, Rodney Weberz, a researcher at Georgia Institute of Technology, is conducting a pioneering investigation experiment (photo source: Journal of Aerosol Science and Technology)

2. Setting optimization: thinner nozzle, lower nozzle temperature, and select the best effect

Secondly, the hardware parameters of different manufacturers are different, and these parameters will affect emissions. Especially when PLA consumables and nylon consumables are used, the influence of printer brand and parameters is more obvious. Some settings also have a significant impact on PM and VOCs emission rates.

A study was conducted at the University of Technology in Brno, where researchers compared the effects of printer settings on ABS, PLA, PET and TPU materials. The results show that when we choose the optimal print setting, we can ensure the success of printing while minimizing emissions; At the same time, when the nozzle temperature is set low, the emissions generated by its materials will be less. Therefore, from the perspective of respiratory health, researchers recommend that printer users set the lowest nozzle temperature possible, even lower than the manufacturer's recommendations. The study also found that the size of the nozzle has a significant impact on the emission rate and particle concentration. For ABS, PET and PLA materials, they found that using a 0.4 mm nozzle produced the least PM. TPU is an exception. When using TPU, the nozzle size increases to 0.6mm, and the discharge is less.

△ Maximum particle formation rate during printing under different nozzle temperature/size settings (photo source: International Journal of Environmental Research and Public Health, "Parameters Affecting Ultrafine Particle Emission in 3D Printing")

The results also showed that the material flow rate or printing speed had little effect on emissions. Therefore, the extruder setting is the most critical factor affecting emissions. Another study using ABS and PLA tests found that the heated printing platform would not increase emissions, but would help to increase particle size and reduce the number of particles more easily.

Almost all researchers point out that proper ventilation method is the key to improve indoor air quality. The user should place the printer in a well ventilated position and install a fan at the exhaust port to achieve the best effect. All ventilation systems shall be equipped with corresponding air filtration system for use. It is recommended to use HEPA filters, which can remove up to 99.95% of the particulates. To reduce VOCs emission, activated carbon filter is the best solution.

3. For open printer, add other supporting devices

It is a good choice to cover the 3D printer with a small ventilated enclosure with an air filter. Research shows that a desktop 3D printer can reduce particle emission by 97% by placing it in an enclosure with filtering and ventilation performance. However, it should be noted that when purchasing, you should check whether the purchased shell is equipped with a HEPA system, because many 3D printer shells on the market are only used to maintain heat, and have no emission effect.

△ Printer shell with HEPA filter specially customized by Alveo3D, a French company (picture source: Alveo3D)

The air purifier uses a fan to suck in air and remove various pollutants through various filtering and disinfection methods. They can play an important role in improving the air quality in the working area of the 3D printer, but it is better to choose the air purifier equipped with HEPA and activated carbon filter. The air filter should be purchased with great care, because the filter specially used for dust and division may not be able to completely remove the particles or VOCs emitted by the 3D printer. Remember to replace the filter screen on the machine regularly.

4. Indoor installation of air quality monitor

The air quality monitor can help users monitor the content of potentially harmful chemicals in the work area in real time. However, there are different conclusions on whether consumer level monitor products are sensitive enough to detect tiny particles emitted during 3D printing. One study showed that the vast majority of solid particulate materials emitted from consumables were between 0.05 and 0.2 microns in size. However, most domestic air quality monitors can only detect particles with the size between 1 and 2.5 microns (defined as PM1-PM2.5). However, some monitors can detect particles below 0.1 μ m (defined as PM0.1).

Some studies indicate that air quality monitors are not necessarily reliable even in advanced research sites. However, if your monitor shows that the PM concentration is higher than 35 micrograms/m3, you should start to find ways to remove the emissions from the work area.

How do I choose to purchase a printer that guarantees air quality?

1. Purchase FDM printer with built-in HEPA filter

Since there is no mature testing standard for the time being, in order to ensure the indoor air quality when using 3D printers, we can start from the 3D printers themselves and the indoor environment to find corresponding solutions. First, you can start with a 3D printer. Now there are many 3D printers with built-in air filters on the market. With these printers, you can save the step of purchasing air filter accessories separately, and control emissions from the "source".

Most consumer 3D printers are not equipped with conventional air filters. Some professional models will be equipped with them, while others need to be additionally installed. Pay special attention when purchasing. The industrial 3D printer is specially designed for the factory and must be equipped with an air filter to meet the safety rules and regulations in the workplace. Users can purchase corresponding 3D printers according to the number of printing models and the environment, but it is better to directly purchase models equipped with filtering systems.

Raise3D

The new Raise3D Pro3 printer is equipped with the Air Flow Manager air flow steward system, which first circulates through the printer chamber and then filters through HEPA. The actual effect is much better than that of the model that only uses HEPA for filtering. The principle may be to make small particles become large dust particles when they contact each other in the cabin circulation process, so that they can be more easily adsorbed or settled.

2. Add air filter for the expandable FDM printer

Some 3D printers do not have their own air filter system, but they also provide air filter accessories matching the equipment. Although it is possible to control emissions from the "source", such 3D printers will need to spend additional costs and steps to add accessories, and the cost will be higher than that of equipment with built-in filters with similar prices and functions.

Zortrax

Zortrax's HEPA top cover (additional $250, about 1500 yuan) is suitable for most Zortrax models. The built-in activated carbon filter can absorb many unpleasant smells during printing, while the HEPA filter can capture most harmful particles.

MakerBot

The Clean Air System of all MakerBot Method and Method X printers (additional installation costs $899, about 6300 yuan) is equipped with a HEPA filter, which is certified by GreenGuard for environmental protection.

Ultimaker

According to the manufacturer of Ultimaker, Ultimaker S5 Air Manager (additional installation costs $925, about 6500 yuan) is equipped with E10 particle filter, which can filter up to 95% of the ultra-fine particles, including a silent fan.

summary

With the development of science and technology, more and more classrooms, colleges and enterprises will use 3D printers, because they can play a huge role in education and scientific research. Although the current data is still insufficient to support the establishment of industry standards, we still need to pay special attention to potential hazards, prevent them before they occur, reduce possible occupational hazards, and protect children from incidents similar to melamine in the past.