Additive Manufacturing Creates New Aerospace Clean Air Challenges
Exploring Solutions for New 3D Printing Airborne Hazards Additive manufacturing (the industrial version of 3D printing) was front and center at AeroDef 2020, with three days devoted to exploring this technology’s potential to overcome low throughput, geometric restrictions, structural defects, and other aerospace and aviation manufacturing challenges.
But for all the 3D buzz, there’s been little public focus on the potential indoor air hazards of using this technology at an industrial level. Additive manufacturing (AM) often involves melting plastic and other complex compounds that can release volatile organic compounds (VOCs) near the printer and the object. Powders and dust are also dislodged and released into the air as objects are removed from the 3D printer upon completion or as jobs accumulate during the process.
According to a recent article by Safety+Health1 magazine that cites a new study from NIOSH researchers2, there are numerous inhalation risks from these 3D printed air particulates, such as:
- Styrene, a carcinogenic particulate found in acrylonitrile butadiene styrene (ABS) filaments
- Caprolactam, produced by printed laybrick, laywood, nylon, and plasticized copolyamide TPE filaments, which is a respiratory irritant
- Other potentially toxic particulates produced by printed feedstock materials in various phases or states, such as liquids, solids, or powders
The article cautions that occupational exposure levels for 3D printer emissions have not been established and recommends ventilation for mitigating possible hazards. But ventilation may not go far enough to protect industrial workers from microscopic filaments or polymer particulates.
Aerospace manufacturers can’t afford for even one of their highly-skilled employees to become ill from working with 3D printers. Fortunately, there are proactive clean air solutions that can filter and destroy potentially toxic VOCs and dust generated by additive manufacturing processes – before these hazards can threaten safety and productivity.
The Processes
The NIOSH study includes a framework for identifying the known hazards from 3D printing (see below table). This framework is defined by specific AM processes, including:
- Material extrusion, involving electrical heating element-induced melting and cooling
- Powder bed fusion, involving high-powered laser or electron beam heating
- Vat photopolymerization, involving ultraviolet-laser induced curing
Potential Hazards of Additive Manufacturing for Aerospace
| Category | Feedstock Materials | Feedstock Form | Binding/Fusing | Most Prominent Potential Hazards |
|---|---|---|---|---|
| Material extrusion | Thermoplastics (may include additives) | Spooled filament, pellet, or granulate | Electrical heating element-induced melting/cooling | Inhalation exposure to VOCs, particulate, additives; burns |
| Powder bed fusion | Metal, ceramic, or plastic | Powder | High-powered laser or electron beam heating | Inhalation/dermal exposure to powder, fume; explosion; laser/radiation exposure |
| Vat photopolymerization | Photopolymer | Liquid resin | Ultraviolet-laser induced curing | Inhalation of VOCs; dermal exposure to resins and solvents, ultraviolet exposure |
| Material jetting | Material jetting Photopolymer or wax | Liquid ink | Ultraviolet-light induced curing | Inhalation of VOCs; dermal exposure to resins and solvents, ultraviolet exposure |
| Binder jetting | Metal, ceramic, plastic, or sand | Powder | Adhesive | Inhalation/dermal exposure to powder; explosion; inhalation of VOCs, dermal exposure to binders |
| Sheet lamination | Metal, ceramic, or plastic | Rolled film or sheet | Adhesive or ultrasonic welding | Inhalation of fumes, VOCs; shock, laser/radiation exposure |
| Directed energy deposition | Metal | Powder or wire | Laser/electron beam heating | Inhalation/dermal exposure to powder, fume; explosion; laser/radiation exposure |
While many industrial-sized printers feature a degree of built-in self-containment for these processes, loose powder or dust is easily dislodged when removing an object from the printer as noted above. Filament powders are complex and potential hazards may vary with each potential aerospace AM application.
The Hazards
The Department of Energy’s Office of Scientific and Technical Information has identified potential health hazards from 3D printed dust, including:
- Skin, eye, and respiratory irritations
- Chemical burns or other threats from toxic metal particles
- Fires or dust deflagrations from combustible dust
In addition to safety hazards, dust can compromise product quality and settle into every crook and crevice of valuable aircraft components and other manufacturing equipment.
OSHA offers tips for reducing dust accumulation, such as using vacuums approved for dust collection and performing regular inspections and diligent housekeeping. Unfortunately, these measures only apply after dust has already circulated throughout a manufacturing facility.
Proactive Solutions
Isolating additive manufacturing processes is key to preventing potential hazards from dust, VOCs, and other particulates before they’re released into an aircraft hangar or other aerospace manufacturing facility.
Duroair engineers industrial air filtration systems that isolate and capture both dust and gaseous particulates that can threaten safety and productivity. Our air filtration systems work with our patented Taper Draft Airflow Technology to create indoor environments that are so clean they exceed OSHA requirements. Our crossdraft airflow pulls air particulates away from employees and collects all toxic particulates and VOCs via multi-stage filtration.
Coupled with a modular enclosure that can be custom-tailored for even large-scale 3D printing processes, Duroair industrial air filtration efficiently removes airborne hazards and recirculates air back into the enclosure – creating a clean air chamber that is impervious to contamination.
This technology also:
- Retracts as needed to allow crane access and won’t interfere with current ventilation infrastructure
- Allows AM processes to be moved when and where needed, without interrupting other cellular workflows
- Prevents contamination from corrosive dust and hazardous fumes that can threaten 3D printing integrity and quality
Plus, Duroair custom-engineered solutions can be tailored for specific aerospace and aviation cellular workflows. Our clean air experts can provide an in-depth evaluation of your hangar or facility to create an industrial air filtration system that will meet your budget and work with your floor plan and space limitations. Contact our industrial clean air experts today for a free consultation.
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