3D Printing Overnight: How to Safely Print & Leave Your 3D Printer Unattended

Want to 3D print a large part? Well, if so, you’ll probably have to leave your 3D printer running overnight.

But, don’t fret because modern 3D printers are super safe, and, as long as you check a few boxes, it’s completely safe to let them run overnight.

First off, you should check that thermal runaway protection is activated on your 3D printer. This way, in the extremely unlikely scenario where the machine overheats, all power is shut off, limiting any damage to just your 3D printer.

And, to be even safer, you can set up a camera near your 3D printer and run a special A.I. software that watches your machine when you’re not. Other optional safety precautions include adding an external temperature sensor and an enclosure to your printer.

In the sections below, I’ve gone over why it should be okay to run your 3D printer unattended overnight and what you can do to further ensure no problems arise.

Is it Dangerous to Print Overnight?

The short answer: not really.

In general, the 3D printing process carries very little risk. And, while people often think that 3D printers can catch on fire, this event is extremely unlikely because FDM 3D printers don’t actually have an open flame. Even if you coated the print bed with gasoline, unless some type of spark or ignition occurs, everything should be fine.

Of course, I don’t suggest testing this because, as you have probably heard, some 3D printers have caught on fire. But, this really only happens under very specific circumstances, like a PSU defect from the factory causing a spark, which ignites hairspray on the print bed, which causes the fire. 

With this in mind, it’s safe to say that you can run a 3D printer, even a sub-$100 one, overnight without worrying about a fire or another dangerous outcome.

Potential Hazards of Overnight Printing

There are a few potential hazards associated with printing a model overnight, and I’ve gone over the main ones in the sections below.



The most dangerous potential hazard of running your 3D printer unattended is overheating. However, I should note that, while overheating is a dangerous issue, it’s also super unlikely.

When overheating does occur, it can damage not just your 3D printer but also the surroundings overnight if the heat is too much. Usually, though, the Thermal Runaway Protection system on 3D printers stops overheating before the problems get out of hand. I’ll go more over Thermal Runaway Protection later!

Print Failures


Print failures, including nozzle clogs and hot end jams, are the most common criminal for overnight prints. Print failures don’t usually cause a hazard because they are usually just related to the appearance and performance of a 3D printed model. But they’re still something to keep an eye out for.



Fumes are another potential hazard for overnight prints. While you can’t see it, your 3D printer is constantly emitting fumes when it melts filament and extrudes it. Most of these fumes are harmless, but some aren’t, especially those in ABS filament.

Luckily, though, you can make sure that fumes don’t become a problem by using an enclosure on your 3D printer, which I’ll talk more about later.



Lastly, there are a handful of other potential hazards for overnight prints that don’t fit in the other sections. These “other” hazards are usually very niche, such as a pet cat jumping on your printer and knocking it over when you’re asleep.

Of course, events like this are extremely unlikely and can’t really be prevented, but you should do your best to try to make sure no external factors cause issues.

How to Safely Print Overnight

There are some things you can do to further ensure that your overnight print is safe and runs smoothly. And, in the sections below, I’ve gone over the best safety precautions:

Enable Thermal Runaway Protection


First off, you MUST enable Thermal Runaway Protection on your 3D printer. Thermal Runaway Protection is a special feature on 3D printer firmware, which runs on the motherboard of every machine.

Thermal Runaway Protection basically tells your printer to shut off all power once it detects that the real temperature (either for the nozzle or bed) far exceeds the expected temperature. The purpose of this firmware feature is to prevent the printer from burning itself and potentially causing a fire.

While every 3D printer manufacturer says they enable Thermal Runaway Protection, you should always double-check that it’s turned on. You can usually do this by manually looking at the firmware’s Configuration file or by seeing if there’s an option for “Thermal Runaway Protection” on the machine’s LCD interface.

If it’s not turned on, either activate it or flash a new firmware version to your printer’s motherboard that has Thermal Runaway Protection enabled. This is the single greatest preventer of fires on 3D printers.

Use a Camera


Secondly, if you’re worried about printing overnight, I strongly urge you to get a camera for your 3D printer. Cameras, when connected to a 3D printer server (e.g. OctoPrint), allow you to remotely monitor your 3D printer. So, if you ever wake up scared one night, you can just pull out your phone and check that everything is okay rather than going downstairs to check.

But, on top of this, you can attach a special artificial intelligence software that uses the camera feed to check that your 3D printer is running smoothly. Specifically, I’m talking about Obico (previously called “The Spaghetti Detective”).

Obico not only uses a very accurate AI program to verify that your print is running properly, but it will also pause (or stop) your 3D print and alert you when it detects an issue. This makes your 3D printer much safer because, obviously, you can’t always be there to watch it, and it also saves you filament.

Setting up Obico is also very easy if you already have a 3D printer server, and you can check out my article about the software to learn more.

Add an External Temperature Sensor


Next, you can add an external temperature sensor to your 3D printer. And, for reference, I’m not talking about adding a second thermistor cable to the hot end; instead, I suggest adding a digital thermometer sensor by the frame of your printer, and configuring it to alert you once the sensor detects that temperatures are significantly above what they should be.

Of course, to do this, you’ll probably have to have some DIY experience with sensors. But, if you’re scared about running your printer overnight, this might help with your worries.

Use an Enclosure


A 3D printer enclosure is a box or container that your 3D printer goes into. An enclosure is a decently popular upgrade for 3D printers because it ensures a high ambient temperature around your printer, allowing you to successfully print high-temp materials like ABS and PC.

Enclosing your 3D printer, though, can also help with ensuring its safety because the container-like structure will make sure no heat from the printer accidentally causes an accident outside of the enclosure.

Additionally, enclosures will trap any fumes produced by your 3D printer so they don’t spread throughout your house. On this note, I recommend adding an air filter or purifier inside or around your enclosure to remove the dangerous particles in the fumes.

Calibrate 3D Printer


Next, calibrating your 3D printer not only helps ensure a successful print but also goes a long way in ensuring the printer is safe and no dangerous issues arise.

There are many ways you can calibrate your 3D printer, and, below, I’ve listed some of the most important methods:

Of course, feel free to use other calibration methods too! The better your printer functions, the less likely it is to fail overnight and the lower chance of safety issues.

Keep Flammable Objects Away

If you didn’t already know, you should keep any and all flammable objects or substances far away from your 3D printer. Even though, as I mentioned, 3D printers don’t have an open flame, heat, in general, shouldn’t go near flammable objects. So, if you have hairspray, acetone, or another flammable substance near your 3D printer, I strongly suggest moving it.

Have a Smoke Detector & Fire Extinguisher


Next, you might want to add a smoke detector and fire extinguisher near your 3D printer. You can buy both online or in any local hardware store, and they can be a lifesaver (literally).

If you add a CO2 detector, I suggest placing it above your 3D printer, such as on the top of the machine’s frame. That’s because smoke travels up (usually) so this position will work best.

And, as for where to put the extinguisher, basically, any place near your printer should work. I suggest making it obviously visible too, so, if someone else sees a fire, they can easily find the extinguisher and use it to put out the fire.

Double Check the Filament is Not Tangled


Tangled filament is probably the problem I’ve run into most with overnight prints. While not related to fire prevention, double-checking that your filament is not tangled is a very important step to ensuring a successful overnight print.

Simply look at your filament spool and make sure the filament strand is organized and not crossed.

Secure the Wires, Cables & Screws


Finally, I suggest securing any wires, cables, screws, or other loose parts on your 3D printer. You can usually do this with some cable ties or by tightening any bolts.

Doing this helps ensure the safety of overnight prints because this eliminates the chance of something falling, breaking, or getting in the way of your printer.

Is a 3D Printer a Potential Fire Hazard?

Yes, but not really.

As I mentioned, there have been a few instances in which a 3D printer has caught fire. However, it’s super unlikely, so I wouldn’t really say it’s an issue you have to worry too much about. As long as you activate Thermal Runaway Protection in your printer’s firmware, you should be good.

Of course, if you’re still worried, you can employ other safety methods, like adding an enclosure, setting up a smoke detector, and adding an A.I.-enabled camera.

Is it Safe to Have a 3D Printer in Your Room?

Yes, for the most part!

I actually have a few 3D printers in my room, and keeping them in your bedroom, while it isn’t exactly advised, certainly isn’t a big problem. But, if you do put a printer in your room, I strongly advise enclosing it and adding an air purifier to ensure the fumes don’t get to you while you’re sleeping.

Can You Pause a 3D Print Overnight?

Yes! You can pause a 3D print job whenever you want!

So, if you’re uncomfortable with printing overnight, you can always pause the print job right before you go to bed, and then resume it when you wake up. If you do this, though, make sure that the print has a brim or raft as you don’t want the part to peel off the print bed during the night.

Do 3D Printers Use a Lot of Electricity?

No! Contrary to some rumors, 3D printers don’t use a lot of electricity. You shouldn’t need to worry about your 3D printer overdrawing power and blowing the breaker.

In fact, I run 8 3D printers off of one standard home outlet and I used to run them all at once. Of course, I don’t suggest doing this, but it didn’t cause a problem.

Bottom Line

Leaving your 3D printer unattended is always scary, even after years of 3D printing experience. But, you have nothing to worry about!

While there have been instances of 3D printers catching on fire, these events are very rare, and 3D printers generally don’t pose a fire hazard because they don’t have an open flame. As long as Thermal Runaway Protection is enabled on your printer’s firmware, you’re safe!

Of course, I realize that this doesn’t satisfy everyone’s worrisome minds, so other ways to ensure a safe and successful overnight print include calibrating your printer beforehand, setting up a CO2 detector, keeping a fire extinguisher nearby, and putting up an enclosure for your 3D printer. And, if you’re still worried, you can even set up a camera with an A.I. software that will detect printing issues and pause your printer before they pose a large threat.

Hope this helps!

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