This article provides answers to the most common questions that Formlabs customers ask about safety when using the Fuse ecosystem. Safety data sheets should be used in safety assessments, whereas this article can be used to quickly answer the questions about the top safety concerns associated with SLS printing.

In general, when working with fine particulates such as Formlabs SLS powders, consider wearing eye protection, impermeable gloves, and a mask. Always consult the safety data sheet (SDS) as the primary source of information to understand safety and handling of Formlabs materials.

Airborne powder concentrations associated with normal use of the Fuse ecosystem are typically significantly below recommended and permissible exposure limits. For example, studies performed at Formlabs SLS R&D facilities, have shown that airborne powder concentrations associated with normal use of the Fuse ecosystem, even with more than a dozen printers in one room, are below 2% of the OSHA permissible exposure limit for the total particulate matter and respirable particulate matter and below 15% of the OSHA permissible exposure limit for carbon black. The normal use of the Fuse ecosystem complies with OSHA dust exposure regulations.

For more information about this study, see this air quality and dust hazard analysis [EN] [DE] [ES] [FR] [IT] [KO].

The risk of powder fire is very low when using the Fuse ecosystem.

SLS powders can catch on fire under certain conditions. Since it is possible for SLS powders to ignite, they should be kept away from ignition sources such as open flames. However, given the nature of the Formlabs powders, the safety features incorporated in the hardware, and regular housekeeping to avoid dust accumulation, the risks of powder fire are very low. For more information about safety with SLS powders, see this air quality and dust hazard analysis [EN] [DE] [ES] [FR] [IT] [KO].

The risk of explosion from SLS powders in the Fuse ecosystem is very low.

Similar to other powders like flour or sawdust, SLS powders can cause an explosion under certain conditions. However, given the nature of the Formlabs powders, the safety features incorporated in the hardware, and regular housekeeping to avoid dust accumulation, the risks of powder explosion are very low. For more information about safety with SLS powders, see this air quality and dust hazard analysis [EN] [DE] [ES] [FR] [IT] [KO].

In general, when working with SLS powders, avoid dispersing the powder in air, regularly clean powder spills and deposits with electrically grounded vacuums approved for dust collection, and keep powder containers tightly closed when not in use. For more information about powder handling, read this support article or the material’s safety data sheet.

Fuse Series printers are Class 1 Laser Devices, the safest classification of laser devices, despite using Class 4 lasers, which are powerful enough to melt plastic powders and cause injury if exposed directly to a person’s eyes or skin.

Fuse Series printers maintain their safe, Class 1 designation because the laser is entirely contained within the printer without a means of escape. Interlocks ensure that lasing does not occur while a user is accessing the machine. Additional safety sensors within the printer detect the presence of external objects or obstructions that may interfere with the laser beams. If an obstruction is detected, the interlock system is triggered, causing the lasers to automatically shut down. The printer also continuously monitors the power supply to the laser components. If a power fluctuation or anomaly is detected, the system activates a safety shutdown procedure. This protects both the user and the printer from potential harm or damage. If these systems are tampered with or fail, there is a risk of exposure to Class 4 laser light. Due to the inability of users to reach the path of the laser during normal operation of the printer, the device is categorized as a Class 1 Laser Product.

Fuse Series printers have several features that help to mitigate possible working hazards. Some of the features that help to ensure a safe user experience include:

• HEPA air filters remove particulates from the printer’s exhaust outlet.
• Interlocks prevent the laser from powering on while users are accessing the printer chamber.
• Users may view the print job through a camera feed displayed on the printer’s touchscreen, allowing for monitoring of the sealed print enclosure.
• The metal enclosure is grounded to prevent static shock and sparks to reduce risk of fire and explosion.
• The Fuse 1 uses a negative pressure to help to contain any airborne particulate within the printer chamber.
• The Fuse 1+ 30W uses partial positive pressure with an airtight design to prevent the escape of particulates and gasses.
• The Fuse 1+ 30W has a rotating agitator in the hopper to improve powder flow. The agitator is torque-limited and will stop mixing if a person or object enters its path.

The Fuse Sift is the product in the Fuse ecosystem in which users come into the greatest contact with SLS powders. Extra care has been taken to engineer a safe, customer-friendly experience. Some of the features of the Fuse Sift that help to ensure a safe working environment include:

• Active ventilation pulls airborne powders into a HEPA filter on the back wall of the unpacking area.
• Vacuum is pulled directly above the powder cartridge and is activated during powder dosing to contain airborne powder particles.
• Semi-enclosed unpacking area contains airborne powder particles and guides them toward the HEPA air filter.
• Grounded metal enclosure prevents static shock and sparks to reduce risk of fire and explosion.
• Build chamber temperature is monitored and displayed to help ensure that users do not handle hot powder.
• Lighting is physically separated from the unpacking area to avoid heat sources in contact with powder.
• Mixer is torque-limited and will stop mixing if a person or object enters its path.
• Vacuum hose integrated into the machine helps maintain a clean work area.

The safety data sheet for each material provides detailed information on safe handling instructions for SLS powders. Formlabs safety data sheets can be found at https://formlabs.com/materials/#data-sheets

Due to its size and weight, do not move or reposition Fuse series printers or the Fuse Sift alone. If either machine needs to be moved, at least two or more individuals should use the lifting straps provided with the units.

Do not lift or reposition the Fuse 1 or Fuse 1+ 30W:

• By grabbing or pulling on the print enclosure door, hopper, hopper lid, filter compartment, filter door, power cable, or any components inside the print enclosure.
• By pushing on any side of the unit while stationary.
• When the build chamber from a previous print is loaded or still cooling in the print enclosure.
• When the print enclosure is still hot from a previous print.

Do not lift or reposition the Fuse Sift:

• By grabbing or pulling on the workspace hood, workspace lip, build chamber enclosure, build chamber latch, or power cable.
• By pushing on any side of the unit while stationary.
• When a hot build chamber is still loaded in the build chamber enclosure.

The print enclosure in Fuse series printers is designed to operate at up to 200 °C (392 °F) and incorporates high-intensity heaters.

Use the provided thermal-insulating silicone gloves when handling a hot build chamber. Do not handle parts from a build chamber without allowing the build chamber to cool for several hours, or until the build chamber temperature has reached ≤ 45 ºC (113 °F). Failure to follow these procedures may result in serious injuries, including burning and/or scalding of skin.

Handle solvents with gloves in a well-ventilated area and keep away from heat, sparks, and open flames. Solvents such as ethanol and isopropyl alcohol evaporate rapidly, and their vapors are flammable, so keep bottles closed whenever possible.

When handling flammable solvents, always consult the safety data sheet (SDS) from the supplier as the primary source of information.

The Fuse 1+ 30W has the ability to use nitrogen as an inert gas atmosphere in the print enclosure. The inert nitrogen atmosphere prevents the thermooxidative degradation of plastic powder. The nitrogen gas is used to displace oxygen in the air within the printer. If nitrogen gas is released into the room containing the Fuse 1+ 30W and displaces the existing oxygen content there (roughly 21%), it may create a significant hazardous situation. For reference, the United States Occupational Safety and Health Administration (OSHA) states that “atmosphere with an oxygen level below 19.5 percent to be oxygen-deficient and immediately dangerous to life or health.”

If you plan to use an inert gas atmosphere with the Fuse 1+ 30W, install an oxygen monitor with an alarm located in the same room as the printer in order to monitor oxygen levels.

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