What is 3D printing?
Three-dimensional “(3D) printing” is a growing technology which involves creating three-dimensional objects by laying down successive layers of materials, which may differ in composition. Initially, a virtual design is created and stored by computer-aided design (CAD) with 3D modeling software, and/or by using a 3D scanner/device. Once a design model (file) is created, a 3D printer/printing application will print the image by laying down definitive, discreet layers, to create the object, layer-by-layer. Images may be simple, with one type of material, or highly complex with different integrated materials.
3D scanners employ one of several technologies, with more common technologies including: “time-of-flight”, “structured/ modulated light”, and volumetric scanning.
3D Printing Applications
3D printing applications are being developed for use in diverse industries, such as: medical/prosthetics, “bio-printing”, aerospace and aviation, foods, and automotive. 3D printing can be useful in any industry where rapid prototyping and subsequent rapid manufacturing are desirable. Personal 3D printers are now becoming readily available for home use and hobbyists.
What are the main hazards associated with 3D printing?
The hazards associated with 3D printing are related to the processes and technologies applied. These may range from: hazards associated with electrical/shock, electromechanical force, burns from molten materials, ultraviolet light (UV)/ laser beams, and to health hazards associated with inhalation of ultrafine and/or toxic smoke, fumes and dusts.
When installing 3D printers, various hazards should be considered for each type technology/application, and the specific work environment where installed.
What are some specific hazards associated with 3D printing processes?
Inhalation and related systemic exposure to hazardous agents – Many 3D printing processes use thermoplastics and other materials, which are heated, extruded, and/or fused using high energy sources. These processes emit ultrafine particle clouds and fumes in the nanoparticle range, (i.e. 1/10,000 millimeter or sub-micron range). For example, 3D printing via material extrusion using polylactic acid (PLA) feedstocks, using relatively low-temperature desktop applications can generate in excess of 20 billion particles per minute. Higher temperature acrylonitrile butadiene styrene (ABS) feedstocks can release in excess of 200 billion particles per minute. Nanoparticles are of concern because they are very small, have large surface areas (low density) and can readily penetrate, interact with, and/or traverse the body’s systems (i.e. skin, lungs, nervous and brain tissues) at the cellular level. Exposure to high concentrations of nanoparticles has been associated with adverse health effects, including: cardio-pulmonary and respiratory effects, cancer, asthma, and nervous system effects. Though PLA feedstocks are intended to be non-toxic and compatible with biological tissues, there may be unknown effects at very high concentrations, particularly in poorly ventilated spaces. The thermal decomposition products of ABS feedstock have been shown to have toxic effects on lab rodents. These hazards may be significant, thus installation designs must consider the adequacy of exhaust ventilation or filtration.
Skin or respiratory sensitizers:
Certain thermoplastics and photopolymers (used in 3D printing) when activated by heat or UV light may contain toxic or hazardous monomers such as acrylates, or other sensitizing agents. U/V light may also pose a radiation hazard to the eyes or skin.
Biological material hazards:
Life and/or Material Science applications involving biological materials, such as use of cells for engineered tissue generation, may expose persons to aerosols containing biological materials or bio-hazardous agents. Appropriate biosafety and other engineering controls must be considered. Consult UNC - Pembroke EH&S Office for assistance and support in determining needed biosafety and/or engineering controls.
Hazards associated with support materials:
Support materials in the 3D print matrix may contain harmful agents (e.g. phenyl phosphates associated with thermoplastic acrylics). These can be hazardous during use, and downstream waste handling.
Powder resins and metals:
Reactive and highly combustible powder metals, as well as other resinous materials may be used in powder bed or direct energy deposition processes. These have applications in the construction of metal/alloy or other structural and functional tools and parts. Finely divided metal powders, such as titanium and aluminum, as well as other resin powders can be spontaneously combustible (pyrophoric) causing fires. The user must eliminate sources of potential ignition and not store the powder materials in a manner which may contribute to an explosion hazard. Class D metal fire extinguishers are required with use of metal powders. Users must follow specific manufacturer instructions and verify that electrical equipment and wiring are suited for the application. These applications use very high heat and may expose users to thermal injury, as well as potential inhalation of the powders or associated fumes.
Do to the hazardous nature of these materials and applications, Standard Operating Procedures (SOPs) are required. Contact the Facility Coordinator and UNC - Pembroke EH&S Office to verify SOP’s are integrated into Unit Specific Plans for the research area, and as part of the Laboratory Research and Safety Plan for the department or work unit.
Consult the 3D printer manufacturer website to locate Safety Data Sheets (SDS’s) (previous material safety data sheets) to understand and evaluate the specific health and safety hazards associated with the 3D print materials used.
As previously noted, in addition to health hazards, examples of equipment-related hazards may include:
- Thermal/ Hot surfaces: Print head block and U/V lamp;
- Electrical/ High voltage: Electrical components, connections including U/V lamp connector, circuits, conductors, etc. operating at 50 volts or higher must be guarded. Electric outlets must be safety-certified with grounding wire intact;
- Ultraviolet radiation/U/V lamp: Don’t look at the lamp; make sure U/V screen is intact; and
- Guarding: Pulleys, chains, belts, rods, carriages, fan blades, rotating/moving parts (i.e. printing assembly), power transmission apparatus and any other type of pinch point must be guarded.
NOTE: Shields/ guards/ covers installed by the manufacturer must not be removed/ remain in place and be utilized.
Consult UNC - Pembroke EH&S Office for support in conducting hazard assessments, and for other controls support as early as possible during 3D printer planning, design, and installation.
What about 3D printer installations and maintenance?
Consumer-Grade 3D Printers: Must be installed and maintained according to manufacturer’s instructions, and in well-ventilated areas.
Industrial-Grade 3D Printing Systems: Must be installed at the direction of the manufacturer, operated by manufacturer-trained users, and serviced by the manufacturer or personnel trained by the manufacturer.
What about Operator/ User training?
Persons working with hazardous chemicals in 3D printing are minimally required to take an EH&S hazard communication class, depending on their work environment:
- Hazard Communication (Hazcom) (Non-Lab Setting), or
- Laboratory Safety & Laboratory Hazard Communication (Laboratory setting).
Industrial grade 3D printing applications shall additionally require orientation/training, as recommended by the manufacturer.
Consult UNC - Pembroke EH&S Office to make sure you receive the correct training(s) before operating a 3D printer. If biomaterials are used, Biological Safety training is required.
General Safety Considerations
Always follow manufacturer guidelines.
- Consult EH&S for a hazard assessment when considering modifications / novel uses.
- Notify coworkers before beginning non-routine and hazardous work.
- To prevent respiratory irritation, ventilate areas where model and support materials are used. Consult Facility Coordinator and UNC - Pembroke EH&S Office for assistance and support with new installations and determining ventilation rates.
- Once a printing job is started, do not open cover, or defeat/override interlock switch.
- If interlock safety switch fails, do not use the printer.
- As determined necessary by hazard assessment, and in addition to all pertinent laboratory personal protective equipment (PPE), chemical protective gloves and suitable dust mask may be required when accessing the printer stage after printing.
- Uncured material may be hazardous; wear suitable/ recommended glove protection.
- If material can splash, wear safety goggles.
- In the event of leak/ spill of printing material cartridges, use solvent-absorbent pads for model/ support material spills. Dispose clean-up materials as chemical waste. Contact UNC - Pembroke EH&S Office when responding to any major spills.
- Keep model and support materials away from areas where cosmetics are applied, or food and drink are stored, prepared or consumed.
Specific Safety Considerations – Chemical-Based Support Material Removal
Support Material Removal by Hand
In addition to standard laboratory safety PPE, wear nitrile gloves and/or cut-resistant gloves and ANSI Z87.1-compliant safety glasses to protect the eyes from projectiles if removing the support materials by hand. Dispose of the used material as solid chemical waste.
Personal Protective Equipment:
To avoid chemical exposure while using the caustic and corrosive bath, create a barrier through personal protective equipment including:
- laboratory coat or smock;
- chemical-protective gloves (suitable for use with applicable chemicals);
Note: Users should refer to a suitable Chemical Compatibility Chart for guidance.
- splash-protective face shield or goggles;
- rubber apron should be worn when pouring large amounts of corrosive or concentrated materials, i.e. more than 1 liter;
- face shield offers additional protection and prevents stray splatters from reaching the face; and
- long pants and shoes that cover and protect the feet - splashes often land below the waist.
Material & Waste Container Labeling
Containers shall be labeled in accordance with the UNCP Hazard Communications Program, found at the EH&S website. Label waste containers and properly store according to UNCP Hazard Communications Program and UNCP Chemical Hygiene Plan.
Contact EH&S for assistance or to schedule chemical waste pick-up.