Systematic ranking of filaments regarding their particulate emissions during fused filament fabrication 3D printing by means of a proposed standard test method

Abstract

The diversity of fused filament fabrication (FFF) filaments continues to grow rapidly as the popularity of FFF‐3D desktop printers for the use as home fabrication devices has been greatly increased in the past decade. Potential harmful emissions and associated health risks when operating indoors have induced many emission studies. However, the lack of standardization of measurements impeded an objectifiable comparison of research findings. Therefore, we designed a chamber‐based standard method, i.e., the strand printing method (SPM), which provides a standardized printing procedure and quantifies systematically the particle emission released from individual FFF‐3D filaments under controlled conditions. Forty‐four marketable filament products were tested. The total number of emitted particles (TP) varied by approximately four orders of magnitude (109 ≤ TP ≤ 1013), indicating that origin of polymers, manufacturer‐specific additives, and undeclared impurities have a strong influence. Our results suggest that TP characterizes an individual filament product and particle emissions cannot be categorized by the polymer type (e.g., PLA or ABS) alone. The user's choice of a filament product is therefore decisive for the exposure to released particles during operation. Thus, choosing a filament product awarded for low emissions seems to be an easily achievable preemptive measure to prevent health hazards.

Materials Requirements in Fused Filament Fabrication: A Framework for the Design of Next‐Generation 3D Printable Thermoplastics and Composites

“…[ 34,352–354 ] For these reasons, the usage of PLA has been regarded as being potentially less harmful for human health. [ 353,355 ] However, Tang and Seeger [ 356 ] have recently pointed out that it is not possible to establish a meaningful ranking of emissions based on the polymer type alone. Besides the polymer type, the addition of fillers, dyes, and other additives (stabilizers and plasticizers, for example), as well as the presence of unknown impurities may also change the thermal stability of the polymer matrix, and thus influence the emission of particles.…”

“…[ 357,358 ] In other terms, the emissions are governed by the “filament product” as a whole, rather than by the polymer type. [ 356 ] For example, Potter et al. [ 359,360 ] demonstrated that not all VOCs can be attributed to the degradation of the polymer backbone, which suggests that some emissions are rather caused by the volatilization or degradation of polymer additives such as plasticizers and stabilizers.…”

“…It should also be mentioned that a sound comparison across the literature is impaired by the variability of the printing conditions. According to Tang and Seeger, [ 356 ] the emissions depend on the printer model (different hardware and software), and on the specific printer settings, with the printing temperature being particularly important. [ 356 ] Stabile et al.…”

“…According to Tang and Seeger, [ 356 ] the emissions depend on the printer model (different hardware and software), and on the specific printer settings, with the printing temperature being particularly important. [ 356 ] Stabile et al. [ 364 ] observed that the same PLA filament did not cause any particle emissions when printed below 220 °C, whereas the emission rates became sensible at 220 °C (6.78 × 10 9 particles min −1 ) and increased by more than one order of magnitude when the temperature was increased up to 240 °C.…”

Microplastics and their Additives in the Indoor Environment

“…Overall, the chemical composition of particles produced by 3D printing is very heterogeneous and influenced by the filament, the chemicals in the printer itself, and its operating conditions. Therefore, the chemical fingerprint of such particles cannot be assigned to a specific polymer [64] …”