3D Printer Safety

If you own or are considering purchasing a 3D printer you should be aware of the potential hazards involved. Please research your printer or the printers you are considering to find out if it has a higher potential for fire and  if there are ways the community has made the printer safer.

Buy a Printer with Safety Features

Your printer should have firmware (software that runs the printer) which has:

  • Hotend and bed thermal runaway check.
  • Minimum temperature check
  • Maximum temperature check

Thermal Runaway: printer is cooling down faster than it should be or not heating fast enough. This check ensures the thermistor (the device that measures temperature), and the hotend (the part that melts the plastic) are performing as expected. If the hotend is being asked to heat to 215 °C but the thermistor is reporting that the temperature is actually going down, there clearly is a problem. Some printers will simply try to heat the hotend more to compensate and this can actually result in a fire.

Max and Min Temp: If the slicer software requests a temperature of 900 °C it will ignore the command. If the printer detects a temperature below expected cold room temperature or something radical like -600 °C – a sign the thermistor is not working. In both cases the printer should stop printing and turn off power to the heat bed and hot end.

Additional Safety Features:

  • Fans spin up to full blast to help prevent the hotend from overheating in the event that the thermistor is incorrectly reporting the temperature or some other temperature related failure has resulted in the hotend attempting to heat up beyond its usable temperature.
  • Printer that detects fans are not working.

Some cheaper printers come with bad wiring, uses wires that are rated for lower than the amperage being sent over them, or has not fully secured wires either in the power supply or on the circuit board running the printer. Check reviews to see if the printer you have or are interested in suffers from this and usually the community will have a solution available.

If you are building the printer from a kit make sure you follow the instructions carefully. This is most important when it comes to wiring the power supply and heat bed. A loose cable can result in a short which can cause a fire if a printer is unable to detect thermal runaway.

Do your research and make sure you are getting a printer that has safety checks enabled and are proven to work.

Fire Alarm

Please buy a fire alarm and put it directly over your printers. The faster you are notified of a catastrophic problem the better chance you have of getting to safety or even saving your property.

Don’t Rely on Fire Suppression Alone

Some people have suggested using a fire suppression system like those found in kitchens. The idea is if a cooking fire gets out of hand the heat will melt a switch that dumps fire suppression powder or foam. This is usually ok for cooking fires because the source of the fire is extinguished (food) and, even with the burner continuing to heat, typically the worst that happens is smoke damage.

I don’t believe this is as useful with 3D Printers because the problem isn’t that the hotend (burner from the example above) is on, but that the hotend is heating well past safe levels due to a printer malfunction. While the initial fire might be suppressed, another one can easily start from molten aluminum reaching other flammable parts on the printer.

Another option is to run your printer in a fireproof or resistant enclosure (steel or concrete). If it is fully enclosed flames would be better contained in the event of a fire.

You should check with your local fire department for expert advice in regards to handling fire like this with a fire suppression system.

Unsupervised 3D Printers in Multi-Unit Homes or Public Buildings

If you are operating your printer in a location where other people’s lives may be at immediate risk in the event of your printer malfunctioning like at a school or apartment building, you should seriously consider never running it unattended.

At a minimum, you should thoroughly test a printer you don’t have experience with to ensure it is reliable and then regularly test to make sure sensors and safety features are working as expected.

Children and Printers

Make sure children are supervised when using a 3D printer. For those of you with small children you should be aware that the hotend on a 3D printer, which melts the plastic, can get up to 300 °C which is 570 °F. This is typically hotter than your electric oven can heat up. The printer bed, if heated, can get up to 90 °C which is 194 °F. Both these temperatures are capable of causing serious burns.

Many printers, especially cheaper ones, do not come with an enclosure. This is to save costs or, in the case of printers primarily used for PLA, to avoid an enclosure heating up too much and negatively affecting print quality. The printers that do have enclosures do not usually have a lock or child safety mechanism.

Particulates and Fumes and Toxic Materials when Printing

This topic isn’t discussed much, but be aware your printer generates invisible, but often smelly, particulates while printing. Some materials are worse than others (ABS compared to PLA). There is not significant research to show printer fumes and particulates are bad for your health, but you might consider using the printer in a room with decent ventilation.

A lot of what has been discussed covers FDM or FFF printers which melt plastic and put it down in layers. Another type of 3D printer that is becoming more popular are SLA printers that use UV cured resin which is toxic before it is cured. You should not touch liquid resin until it has been washed in alcohol and cured in UV light.

Don’t Take My Word For It

Hackaday –  3D Printer Halts and Catches Fire

Hackaday – Don’t Leave 3D Printers Unattended

Thingiverse – Anet A8 almost burned down my house

Punished Props – Avoid a Fire Hazard

Maker’s Muse looks at safety when it comes to SLS printers that use resin:

Maker’s Muse – Resin 3D Printing Safety – Important for Beginners!

Thomas Sanladerer – Everything you need to know to make your 3d printer fireproof!

Thomas Sanladerer – Testing my printers for fire hazards – results all over the place…

More advanced users can modify the firmware on their printers using Marlin to enable safety features:

Thomas Sanladerer – Maker your 3D printer safer: Marlin configuration!

Damaged thermistor reports the wrong temperature and hotend continues to heat until fire in this test. Example of what can happen if your printer does not have thermal runaway protection:

Chris Bate – Hotend thermal runaway test #2