Research

EPA scientists explore VOC emissions of 3D printed carbon fiber materials

Over the past few years,volatile organic compound (VOC) emissions, a bi-product of the FFF process, have been the subject of several studies. In 2017, a study funded bySajtom Light Future Ltd., in Poland, concluded that with adequate ventilation, the melting of materials like ABS, PLA, PET, and nylon does not cause harm to its users.

UL的两年调查报告的发现have also found that exposure to particles and VOC emissions produced by 3D printing processes are generally low when applying appropriate precautions.

Now, scientists from the美国环境保护局(EPA) are studyingVOC emissions from ABS filament that contains carbon nano fiber reinforcement. Again, the same rules surrounding adequate ventilation would apply in this case, butthrough collaboration withtheConsumer Products Safety Commission(CPSC) and theNational Nanotechnology Initiative(NNI), the EPA team are seeking to provide a detailed update to the literature on this topic.

ABS + CNT filament 3D printed to study VOC emissions. Image via the U.S. EPA.
ABS + carbon nanotube filaments (CNT) filament 3D printed to study VOC emissions. Image via the U.S. EPA.

3D printing nanomaterials

EPA’s researche is exploring the unique chemical and physical features ofnanomaterials, including size, shape, chemical composition, and stability, to help develop predictive models determining which may pose a higher probability of risk. As stated by the EPA, such nanomaterials are in more than 1,300 commercial products such as medical equipment, textiles, fuel additives, and cosmetics.

为了了解纳米材料对人类和环境健康的影响,使用市售的ABS细丝与Lulzbot TAZ 3D打印机确定如何VOC emissionschanged. In doing so, VOC emissions were quantified and characterized by carbon nanotube filaments (CNT) under a variety of conditions to simulate the different heating, melting, and forming of plastics during 3D printing.

Al-Abed博士的研究小组仔细考虑的脾气ature, length of time the material was heated, and oxygen concentration at the nozzle. These factors were replicated inside a customized reactor and mass spectrometer, otherwise known as a System for Thermal Diagnostic Studies (STDS), to identify combustion-related emission.

A diagram of the System for Thermal Diagnostic Studies (STDS)

Trapping VOC emissions

A comparison was made between the VOC emissions from the CNT infused filament and the ‘plain’ ABS filament. The team found that the material with CNT emitted two new VOC gasses which could potentially pose an inhalation hazard to users 3D printing several kilograms of material.

Furthermore, the researchers concluded that increased print temperature had the most significant effect on increasing VOC emissions, followed by the increased length of time heating the material. CNT also demonstrated the ability to ‘trap’ certain VOC gasses in particulates of 3D printed plastic.

The study notes that the researcher’s instruments could not directly measure these particulates, thus, further investigations will be needed to understand their potential impacts on human health.

For further reading on these findings “VOC3D打印过程中碳纳米管复合材料的排放和地层机制can be found online in环境科学技术journal.It由菲利普·波特(Phillip M.

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特色的图像显示FFF / FDM 3D printing. Photo via the U.S. EPA.