3D Printer Safety

FDM Printing Hazards and Safety

Hazard Awareness

Two general hazards should be noted when working with fused deposition modeling (FDM) printers: mechanical hazards, such as hot extruders and motors; and emissions in the form of outgassing and ultra-fine particles produced during the filament melting and extrusion process.

Mechanical Hazards

Specific details on mechanical hazards of FDM printers are given below:

  • Several components of FDM printers present hazards. For FDM printers, the heated print bed can reach temperatures of 100 °C, and the heater block and nozzle on the extruder can reach temperatures of 270 °C. Additionally, the motors driving the extruder and the axis movements can also be hot.
  • FDM printers have many components that move quickly and with relatively little clearance to other components on the printers.
  • Tools used to remove prints from the print bed are often sharp.

Emissions

Specific details on the hazards of emissions produced by FDM printers are given below:

  • Ultrafine Particles (UFP): UFPs are defined as particles with a diameter of less than 0.1 micron [1]. 3D printers are considered as high-emitters of UFPs. Rate of UFP emissions is highly dependent on the type of filament used. Polylactic acid (PLA) filaments typically have the lowest emission rate of all filaments, with a UFP emission rate of  particles per minute [2]. Acrylonitrile butadiene styrene (ABS) filaments tend to have the highest emission rates, with UFP emission rates of  to  particles per minute [2].
  • Volatile Organic Compounds (VOC): The process of melting thermoplastics, as is done in FDM printing, emits VOCs. Types and rate of VOCs emitted is completely dependent on the type of filament used.

Risk Assessment

Mechanical Hazards

  • Touching the heater block, nozzle, heated print bed, or motors while the printer is powered on and preheated could result in minor burns.
  • Touching the printer while the extruder and axis carriages are moving could result in the skin being caught or pinched.
  • Sharp removal tools could cut skin.

Emissions

  • Health effects of UFP inhalation is relatively poorly characterized. However, UFPs do tend to deposit in the head airways and the pulmonary and alveolar regions of the lung [1]. To compare the UFP emission rates of printers with other typical activities, printing with PLA has a similar UFP emission rate as cooking with an electric frying pan, and printing with ABS has a similar UFP emission rate as grilling food on a stove at low power [1].

Figure 1 - Emission rate (particles per minute) for various filament types [2]

  • Health effects of encountering VOCs is highly dependent on the types of VOCs, which is in turn highly dependent on the type of filament used. Primary VOC emissions from PLA include lactide and methyl methylacrylate [3]. The latter is qualified as a respiratory irritant in humans [4]. The primary ABS VOC emission is styrene, which is classified as a possible carcinogen in humans [5]. Other materials will emit different VOCs that will have different potential health effects.

Figure 2 -  Estimated emission rates for different filament materials [2]

Mitigation Techniques and Controls

  • Hazards and risks posed by the mechanical hazards can be mitigated by careful use of the printers and removal tools. Ensuring that the nozzle, heater block, and motors have had sufficient time to cool before touching the printer will prevent any accidental burns (a temperature readout of the nozzle and heater block is usually provided on a screen by most FDM printers). Refraining from touching the printer after a print has been started would prevent fingers or clothing from being caught by the moving extruder and axes. Additionally, placing the printer in an enclosures prevents accidental contact with the printers.
  • Risks associated with UFPs and VOCs are typically mitigated in the same way. Limiting time spent in close proximity to running 3D printers reduces contact with and inhalation of UFPs and VOCs. Operating printers in well ventilated locations reduces the quantities of UFPs and VOCs present in the surrounding air. Isolating the UFPs and VOCs in a sealed enclosure under a slight negative pressure is also effective [6]. Additionally, emissions can be reduced by choosing to print with PLA or another low emitter material instead of ABS or other high emitter materials.

Regulations

3D printing has relatively little regulation, and no relevant regulations specific to 3D printing could be found for the purposes of this document.

References

[1] B. Stephens, P. Azimi, Z. El Orch and T. Ramos, "Ultrafine particle emissions from desktop 3D printers," Atmospheric Environment, vol. 79, pp. 334-339, 2013.

[2] P. Azimi, D. Zhao, C. Pouzet, N. E. Crain and B. Stephens, "Emissions of Ultrafine Particles and Volatile Organic Compounds from Commercially Available Desktop Three-Dimensional Printers with Multiple Filaments," Environmental Science and Technology, vol. 50, no. 3, pp. 1260-1268, 2016.

[3] A. Davis, M. Black, Q. Zhang, J. P. S. Wong and R. Weber, "Fine Particulate and Chemical Emissions from Desktop 3D Printers," in ASHRAE Annual Conference, St. Louis, 2016.

[4] "Methyl methacrylate; CASRN 80-62-6," U. S. Environmental Protection Agency, 1998.

[5] "IARC Monographs on the Evaluation of Carcinogenic Risks to Humans," Internation Agency for Research on Cancer, Lyon, 2002.

[6] T. L. Zontek, B. R. Ogle, J. T. Jankovic and S. M. Hollenbeck, "An exposure assessment of desktop 3D printing," Journal of Chemical Health and Safety, vol. 24, no. 3, pp. 15-25, 2017.

 

Written by Kelly Mathesius 2/26/18