3D Printing Safety

Additive manufacturing or 3D printing involves the layering of successive layers of material to create or replicate 3D objects.  Depending on the printer, 3D objects are created through extrusion, sintering or curing.  3D printers are now commonly used in many industries including, but not limited to, aerospace, architecture, automotive, consumer products, defense, dentistry, education, and medical fields.  As such, 3D printing has also become common in university labs, classrooms, and research areas.  The following guidance is based on current research and evaluations regarding the risk to human health and safety.   

Multiple types of 3D printers are available to create 3D objects. The most commonly used types of 3D printers are listed below.

Material extrusion [fused deposition modeling (FDM)]: FDM printers use athermoplastic filament, which is heated to its melting point, to create a 3D object. This is the most common type of 3D printer.

Vat polymerization [stereolithography (SLA)]: Vat polymerization uses a liquid photopolymer resin to create a model and then cure each layer of resin using an ultraviolet (UV) laser or digital processing lamp.

Material jetting: Material jetting selectively deposits droplets of feed material onto a build platform, allows the droplets to cool and solidify and then builds on the solidified droplets to create a 3D object.

Binder jetting: Binder jetting distributes alayer of powder onto a building platform and then applies a liquid bonding agent (i.e., a glue) to bond the particle layers together to create a 3D object. 

Powder bed fusion [Selective Laser Sintering (SLS)]: SLS deposits a thin layer of plastic powder or metal powder that is a melted by a laser on a building platform. 3D objects are created through layer-by-layer construction in the powder bed. Some finely divided metal powders are pyrophoric and must only be handled in a device that maintains an inert atmosphere in the print area.

Directed energy deposition (DED): DED uses a laser or electron beam to a melt material (usually metal powders or wires) from the nozzle of a multi-axis arm as it is being deposited. 

Sheet lamination: Sheet lamination creates 3D objects by using a laser or a sharp blade to cut and bond thin-layered materials (e.g., paper, aluminum foil, etc.) together layer-by-layer.

3D printing involves the melting of plastics [Acrylonitrile Butadiene Styrene (ABS), Polylactic Acid (PLA), Polyvinyl alcohol (PVA), Polycarbonate (PC), etc.], metals (steel, aluminum, titanium, copper, silver, gold, nickel, etc.), composites, and photopolymers.  Exposure to emissions from the melting of print media could lead to negative health effects.  The known hazards associated with 3D printing are as follows:

Biological: 3D printers used to create cells and/or engineered tissues may release biohazardous aerosols.

Flammability: The finely divided metal powders (e.g., aluminum, titanium, etc.) or resins used in some 3D printers can be spontaneously combustible (pyrophoric), leading to fires. Contact Environmental Health & Safety prior to using printers with finely divided metal powders/resins. 

Corrosive Baths:  Support material can be removed by placing prints into a heated corrosive bath containing sodium hydroxide or other caustic chemicals.  Exposure to these chemicals may cause serious burns, scarring, or vision damage.  

Vapor Baths:  ABS objects can be "smoothed" or "polished" by placing them in a closed vessel filled with small quantities of acetone or other organic solvent, which vaporizes and reacts with the ABS plastic.  These solvents are ususally flammable and can cause symptoms such as headache, nausea, and respiratory tract irritation, when inhaled.     

Sensitizers: 3D printer by-products from the melting of particular thermoplastics and photopolymers can cause allergic reactions upon contact or inhalation. 

Toxicity: 3D printers using certain print media have been shown to emit volatile organic compounds (VOCs).  Some VOCs have been linked to eye, nose and throat irritation, headaches, damage to the liver, kidney and central nervous system and cancer.

Ultrafine particles (UFPs): The health effects associated with exposure to UFPs (i.e., particles lessthan 100 nm) continue to be studied.  Recent studies have indicated that UFPs can act as a gas and penetrate deep into the lungs.  These particles have the ability to produce inflammatory responses in cardiovascular and respiratory systems.  

Ultraviolet radiation: 3D printers using laserstomelt print media can emit ultraviolet radiation. Exposure to ultraviolet radiation may result in acute or chronic effects on the skin, eyes and immune system.

Inert Gases:  3D printers may use inert gases such as nitrogen or argon to create a noncombustible atmoshphere in the printing chamber, or as part of the aerosolization and deposition process.  If not properly contained, inert gases may displace oxygen in the space creating an asphyxiation hazard.   

Hot surfaces: Contact with the print head block and/or UV lamp can cause burns.

Electrical: Unguarded electrical components in some 3D printers could pose a risk of electrical shock.

Moving parts: 3D printers with ingoing nip points and/or rotating parts can cause pinch or crush injuries.

In order to reduce exposure to the hazards associated with 3D printers, the following controls are recommended.

Training:

• Employees working in labs with 3D printers are required to complete General Lab Safety Training through Environmental Health & Safety.
• Employees working in non-lab areas with 3D printers are required to complete HAZCOM Right to Know (RTK) Training through Environmental Health & Safety.
• Anyone working with 3D printers in university-managed spaces must be provided a copy of the 3D Printer Safety guidelines. 

Registration:

3D printers using class 3B, 3R, or 4 laser systems must be registered with the EHS Laser Safety Officer.  Laser use must comply with all requirements of the Laser Safety Program, as applicable.

Work Practices:

• Install, use, and maintain 3D printers as outlined in the manufacturer’s instructions.
• Since 3D printers run for extended periods, rooms/labs should avoid altering ventilation rates based on occupancy sensors, unless local exhaust is being used to remove emissions.  Use within a chemical fume is optimal. 
• Use 3D printers in well-ventilated areas.  Environmental Health & Safety recommends keeping 3D printers in rooms with 5-10 fresh air changes per hour.  Also, limit the number of printers per room.  One printer per standard office space (~150 square feet) for a non-lab area can be used as a guideline.  Multiple 3D printers in the same room may be possible based on the ventilation rate, enclosures and room size.
• Fully enclose (preferred) or cover 3D printers to limit exposure to VOCs and UFPs.
• An eyewash and safety shower is required in the immediate work area if corrosive materials are present or used in the printing process.
• Eating or drinking is not allowed in areas where 3D printers are being used.
• Avoid contact with heated surfaces to prevent burns.
• Maintain a safe distance from the printer(s) to limit inhalation of emitted particles.
• Live parts on 3D printers operating at 50 volts or more must be guarded against accidental contact.
• 3D printers with ingoing nip points and/or rotating parts must be properly guarded. (i.e., no exposed belts, gears, pulleys or other moving parts or points of operation).
• Store print media and other chemicals associated with the printing process as outlined in the manufacturer’s instructions.
• Choose a low-emitting printer and filament, if feasible.
• Safety Data Sheets (SDS) must be present and accessible in the immediate work area for all print media and other chemical products involved in the printing process.

Personal protective equipment:

• Eye protection recommended by the manufacturer in safety data sheets/printer specifications is required (if applicable).
• Gloves recommended by the manufacturer must be worn while handling print media and other chemicals associated with the printing process (if applicable).
• Respirators may be necessary for use with some 3D printers (e.g., metal and ceramic powders). If employees are required or voluntarily choose to wear respirators, they must comply with the requirements of the Virginia Tech Respirator Program.

Please use this Checklist to ensure your purchase request can be processed efficiently.