3D Printers

Introduction

Concerns have been raised about potential inhalation exposure of ultrafine particles and fumes from 3D printers, however, the scientific evidence is still being developed internationally. It is therefore sensible to apply a precautionary principle and adopt control measures where there is a potential for harm, for example to control at source exposure to volatile organic compounds (VOCs) and large numbers of ultrafine particles (UFPs). 

Whilst sufficient testing on the possible long term health effects has not been carried out, it is believed those with respiratory health issues, including asthma, would be most at risk. Long-term exposure to 3D printer fumes may also increase the potential risk for users such as technicians, who work for extended periods in proximity to multiple 3D printers. 3D printers also pose a fire risk and suitable controls should be put in place to minimise the risk. 

The recommendations in this guidance are based on HSE research IRR146; although this research was produced in 2019 and 3D printing has developed substantially since then, there is no new research from HSE to the contrary. If Schools/Depts wish work outside of the recommended controls outlined below, they should ensure there is a robust risk assessment in place and must be able to show they can obtain a similar standard of emission control to the recommendations given in this guidance. In such circumstances, Schools/Depts should contact the Health and Safety Department to discuss further.

General risk assessments, laser risk assessments (if applicable) and COSHH risk assessments must be conducted for 3D printer use, and the manufacturer's information and component Safety Data Sheets (SDS) should be referred to.

Types of 3D printing

There are various 3D printing technologies, however, the most common used technology is FFF (fused filament fabrication), also known as FDM (Fused Deposition Modelling) where the object is created by laying down melted plastic filament in a series of layers. The adjacent layers cool and bond together before the next layer is deposited. The most common filament used in university settings is polylactic acid (PLA). In addition to 3D FFF printers using plastics, metal 3D FFF printers are becoming more common. The HSE recommends that whilst metal 3D FFF printing technology advances, consideration should be given to potential harmful exposures from these machines given the established evidence from traditional industries that occupational exposure to metals, as particles fumes or through skin contact, can cause various respiratory diseases. 

Another common 3D printing technique is stereolithography (SLA); these 3D printers use a laser (UV wavelength) to cure the resin. A third common process is Selective Laser Sintering (SLS), which also uses a laser. Contact the Radiation Protection Unit through the link at the end of this document for further advice and guidance.

Hazards

The following are possible hazards that should be considered when carrying out a risk assessment for 3D printer use: 

• Ultrafine particle emissions
• Lasers
• Chemical emissions
• Moving components
• Heated components / fire caused by overheating
• Electricity
• Heavy equipment
• Hazardous waste
• Cleaning chemicals 

Recommended control measures

• Purchase suitable equipment: printers should be UKCA/CE marked and have an emergency shut off. Where printers do not have emergency shuts offs, room isolation should be provided. Printers should be purchased as fully enclosed and include filters to remove particulate and chemical emissions. Printers which are not enclosed should have enclosures retrofitted. 

  Enclosures protect against the risk of fire and particulate exposure, which is particularly important for technicians and other users who may be subject to long-term exposure to printer fumes. HSE Laboratory research found that when a filtered enclosing hood was placed over the 3D printer this reduced particle emissions released to the room by 97% when exhausting air from the hood and by 99% in the recirculating air mode. Enclosures also protect against laser hazards and access to very hot components. HSE recommend a clearance time before opening the enclose once printing is complete. See further information below.

• Filters: filter types that are recommended by the manufacturer, should be changed according to supplier’s instructions; users may need to note how long the machine is in use to determine when they should be changed.
• Location: rooms housing printers should be well ventilated, additional ventilation maybe required as laser printers produce additional heat. Access to the space should be suitably controlled with sufficient space to move around the machines.
• Suitable filament: wherever possible use PLA to reduce the risk from fumes and particulate emissions. Filaments that allow a lower nozzle temperate should be used wherever possible. If the risk assessment or COSHH assessment identifies that filament other than PLA should be used, further controls, as set out in the filament Safety Data Sheet (SDS), should be implemented. Filaments can deteriorate due to the effects of temperature, humidity and light, so should be stored in sealed, dry and dark containers. Filament should be purchased from a reputable supplier.
• Nozzle temperature: use the lowest nozzle temperature practicable for the application, as specified by the filament supplier. This is important as particle emission rates have been shown to increase and the average particle size decrease as 3D printer nozzle temperature increases.
• Procedures:
  • Technicians/users should try to reduce the amount of time spent in rooms where 3D printers are operating wherever possible. Do not watch the object being created unless absolutely necessary. Consider segregating the printer and workspaces if the printer is going to be continuously or regularly used each day.
  • Enclosed hoods should be left in place once printing has finished for a minimum of 20 minutes to allow enough clearance time for contaminants and to allow cooling of the heated elements. HSE Laboratory research has found that removing the enclosing hood before the end of the 20 minutes ‘clearance time’ could result in exposure to particulate and VOC emissions produced during the printing process. Instructions should be supplied by the manufacturer of the safety cabinet or hood to include specified ‘clearance times’ after the print has completed before opening the enclosure. This advice should be closely followed by the printer operator to avoid risks for inhalation and ingestion of particulates and VOC.
  • Due to the fire risk from the heat produced, the printing process should be monitored to check for overheating. If overnight/extended periods of printing are planned, this should only take place in fully enclosed printers with fitted fire suppression systems. A SSoW should be undertaken for any overnight printing. Schools/Depts should ensure there are procedures in place to alert those responsible for closing the building that there is overnight printing taking place. It is recommended that notice is also left in place adjacent to the printer with contact details in case of emergency.
• Cleaning and maintenance: machines must be switched off and isolated from the mains before cleaning or carrying out maintenance. Only competent persons should carry out cleaning and maintenance work. If maintenance work is required when the printer is ‘live’, a suitable SSOW and risk assessment must be in place and this activity should only be carried out when another member of staff is present in case of emergencies.
• Manual handling aids: use a dedicated location for the printers and fix them in place. If printers need to be moved, ensure suitable lifting equipment and trolleys are used.
• Electrical safety: visually check that all electrical connections are in a good condition before using printer. Ensure that the machine is correctly installed. 

If there are any issues or questions about meeting the recommendations in this guidance, the Health and Safety Department should be contact at health.safety@ed.ac.uk to discuss further.

Additional guidance in the safe use of 3D laser printers is also issued by the University’s Radiation Protection Unit. To ensure ALL hazards and guidance are addressed, please refer to all other issued guidance: 

• Radiation Protection Unit guidance 

   

Useful links

RR1146 - Measuring and controlling emissions from polymer filament desktop 3D printers (hse.gov.uk)

G276 - 3D Printing in Schools and Colleges Managing the Risks (cleapss.org.uk)