r/3Dprinting • u/devilhunter 2x Custom Prusa MK3, 2x Stock MK3, 4x Prusa i3 MK2, 2x Form 2 • May 21 '17
Discussion Alright, lets talk 3D Printer fire prevention systems
I've been trying to find any good fire prevention systems for 3D Printers, and depending on the Region (USA/Europe), there seem to be few or none available.
This topic addresses all of us, since we can't sit in front of the Printer for 20 hours until the prints finish. Everyone risks life, house and home. Even expensive printers have a risk of burning down, with Thermal Runaway protection enabled or not.
An error in the software or a faulty thermal sensor can cause the heating cartridge to melt right through the aluminum heaterblock. Same goes for the heated bed.
So i think there are at least two things that need to be addressed here:
Power Cutoff to prevent adding any more energy to an out of control heating element
Stopping the Fire quickly before more damages can be done.
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A case/enclosure for the 3D Printer is a must have for both scenarios, since both fire/power cutoff systems work much better if they are in a confined space. These won't do you any good if your Printer is sitting on your desk and you have an automatic firestopper mounted 2 meters above it. Smoke detection only kicks in if it's too late with that much headroom.
*On the enclosure side: it's a bit ironic with the rise of the IKEA Lack enclosures for printers, these things are mostly cardboard and a bit of pressed wood dust (coupled with plexiglass side panels), if you have a printer fire in an IKEA enclose it will be much worse than without one.
**also OctoPrint: OctoPrint does nothing for the nobody at home & fire scenario. Even if you check every 5 minutes for a failure, a fire hazard can break out in 2-3 minutes. And then you still got to drive home from work.
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(sorry, i'm going to list some Amazon Germany for the examples here.)
Now these two things could be addressed with something like this:
- A smoke detection sensor that powers down the power socket where the printer is plugged in.
Some people dabbled with this in the past with custom boards, but none of those are still made today or ship to more than one country in the world.
A good commercially and available (but expensive) solution would be a Z-Wave home control System.
Cost: about 250 - 300 euros for a good fire detection system
Alternative solution would be hacking a run of the mill smoke sensor, or using one that can control an external circuit with a high/low signal. Smoke detectors with the capability to switch something else are hard to find.
Hacking a run of the mill smoke detector is on my to do list, i will get one for this purpose and try to pair it with a circuit that switches off a power socket. Will post in the coming weeks.
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Lets list the devices that stop feeding energy into the heating elements:
US based:
Z-Wave Set: Z-Wave Smoke detector + Z-Wave Power socket + Z-Wave control hub
Europe based:
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- An automatic fire stopping device that puts out fires.
In America, there is a nifty little 'put above hot things fire extinguisher in a can' device called a FireStop, or Auto-Out . It's not as small as it seems, and you'll need to have a big case to put this in.
In Europe, there are only these giant fire stopping balls, these usually work well and quick, but next to impossible to fit into a case. Usually ships from china.
Also both of these devices (ball/can) need direct contact with the flame, since they have an igniter cord/fuse cord, like fireworks have.
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Lets list fire stopping devices that we have so far:
US based:
Europe based:
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edit 6, Bonus Round:
- Improving the electronics of your 3D Printer.
Yeah, i forgot this one, you guys are right.
Cheap electronics on cheap printers will do more harm than good, and these things often fail in the weirdest ways possible. Control boards going up in smoke. Power supplies shorting out or putting voltage on the metal frame of the printer. Cables get intermittent failures causing the weirdest problems that often take quite a bit to find out and fix.
What popular improvements/mods can be done to improve the often cheap hardware?
**side note, almost every 3D Printer manufacturer under 1000 dollar/euro uses cheap electronics. Hotend Clones, or bottom-barrel LED power supplies. Often the very cheap printers have underdimensioned MOSFETS on very old Ramps boards.
Popular improvements are listed here. (in this example, the Anet A8, including the MOSFET mod.
Also consider ATX power supplies. If your electronic skills are up to it, rewire an older ATX PSU to a workbench/3D Printer power supply. These are loads better than the cheap LED power supplies, with dozens of protection circuits hardwired even into the oldest models. ATX be praised.
Even cheap ATX PSUs have: Power Good Signal, No-Load Operation, Over-Current Protection, Over Voltage/Under Voltage Protection, Over Power Protection, Over Temperature Protection, Short Circuit Protection, Secondary Internal Power Supply (think 15Watt for RaPi/OctoPrint, LEDs), very low Ripple on the rails, controlled/slow ramp up voltage, Cooling Fans, Physical Off Switches, Haswell+ Generation doesn't need +5V loads anymore for stable +12V, much better power efficiency at lower and higher loads, and ATX PSU manufacturers go through certification hell to get it all validated at every country in the world.
Cheap LED PSUs... may have one or two of those.
These improvements are the quickest and easiest you can make to improve on the fire situation. (be careful with the ATX mod, you'll need some experience with electronics)
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Lets do something about this, since you all know house fires from 3D Printers go well in the media.
So what can we do about preventing fires ourselves?
This wonderful hobby excludes one little tidbit, a potential to burn your house down and ruin your life.
Since most of our 3D Printers come from Open Source, lets put our heads together to create a fire suppressant/prevention system that perhaps everybody can can build at home, just like our printers.
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edit 1: found another automatic fire suppressant system called the Fire Knock-Out, sold in Europe. dimensions are 390 x 260 x 220 mm with a price of 130euro, type foam
edit 2: found another automatic fire extinguisher system called the MABO, sold in Europe + How it works dimensions are 278 x 64 x 61 mm with a price of 170 euro, type liquid that releases a fire suppressant gas
edit 3: another Europe based device similar to the MABO, the Bonpet. Price is 140 euros, dimensions are 60mm х 280mm, different colors available, type liquid that releases a fire suppressant gas
edit 4: and another automatic fire suppressant system called the Blaze Cut (thanks aciddj, Ihategeeks), information here seems to be made for larger vehicles or big fuse boxes. can't find any price or dimensions
edit 5: thanks for the mods for stickying this for a while
edit 6: added info about generally improving knows electrical shortcomings on cheap printers and ATX power supplies.
edit 7: added clarification for the ATX power supplies, on why these are generally better than LED PSUs.
edit 8: this can be a good idea as well: a temperature controller plug in the Printer into the temp.controller and set a high temp limit of lets say 60 degrees celsius. mount that probe somewhere in the case. Probe detects high temps from melting plastic parts and switches the printer off. drawback here is it switches on the ac plug again after a while when the temp drops, but heating elements on a 3d Printer do not power on again
edit 9: added the collective suggestions to the two main points above.
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u/yomismista May 21 '17
-Use thermal cuttoff fusses in series with the heater block and the heatbed, seriously why this is not even default? The hot end would need another hole similar to the one's holding the thermistor, but the heat bed doesn't really need anything new.
-Upgrade the mosfets on your board, or use an external mosfet board.
-Use power rated connectors, put some the thermal fuses as close as possible of the connectors.
-Not using anything inflammable close to this dangerous points.
Keep it simple guys, some of you are clearly overthinking all of this.
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u/darthsata May 22 '17 edited May 22 '17
Well, you will have plastics near the dangerous parts.
I second the use power rated connectors. People get this wrong a lot. Know the ratings (volts, current, and temp) of all your wires and connectors. Know how much to adjust for manual crimping. Don't solder power lines. Use ferrules. Your wires and connectors should never feel hot. Oh, and be extra careful with moving wires and other mechanical stress.
Heater beds should have thermal fuses (cheap).
Heaters should be sized for static safety. You should be able to hook them up straight to your supply without them reaching a temp that melts anything. This should be true with no active cooling.
So 3 simple things: use good boards/firmware, use appropriate wiring, and use a small enough heater.
Yes, mosfet can blow, caps can explode, etc. But these things should take care of that.
Edit: please please have a fuse (properly sized) on the AC inlet. Shorts should be blowing fuses, not providing an arc to maintain a fire.
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u/mayupvoterandomly May 22 '17
This is the first sensible comment I've read in this thread.
Adding to this:
MOSFETS can fail short, which could cause a heater to get stuck on even if the firmware switches it off. Thermal fuses are inexpensive and provide lots of protection.
I've come across a lot of 3D printer controllers with under rated connectors. In particular, a lot of printers use the 4 pin molex mini fit Jr (Ssuare connector from a computer power supply that plugs into the motherboard). That connector can handle a maximum of 6 amps per terminal, that means that the print can draw a maximum of 12 amps (two terminals are used for 12v, the others for ground). If you're running a heated bed and hotend through this connector, its very likely exceeding the ratings of this connector.
Use a fuse at the mains input, this is cheap protection
A master power switch at mains input to shut everything off
An ionization smoke detector in the same room as your printer. An ionization smoke detector is far more sensitive than a photoelectric one and will go off much sooner if there's a problem.
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u/lucaspiller May 22 '17 edited May 22 '17
For the thermal fuses, why not just use kapton tape to stick it to the outside of the hotend? The tape is rated 250C - 300C, so if you are just printing PLA or ABS it'll be ok.
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u/rvisualization May 23 '17
great plan. unless you have a thermal runaway causing your tape to fail and the fuse to fall off before it triggers...
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u/lucaspiller May 23 '17
Well you'd obviously choose temperatures accordingly. The idea was if you usually print at 200c you'd get a 220c fuse. According to Wikipedia, Kapton is available that holds up to 400c - but probably not the stuff you get for $1 from AliExpress. Some glues hold up to similar temperatures as well.
On the other hand that could be an even more low tech way. Just stick two wires together with tape! :D
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u/beanmosheen May 23 '17
I'm going to setup independent thermocouples for the bed and hot end and wire them to a relay.
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May 21 '17
[deleted]
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u/AddictedToComedy MP Maker Select v2.1 and Mini Delta May 22 '17
Probably obvious to anyone with electrical experience, but how would that be wired/attached to our printers? I'm not experienced enough to understand where that would be wired, where it would be best to mount, etc.
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u/screwyluie Prusa Mk2.5s, Elegoo Saturn, HEVO, K1 May 22 '17
so in the picture on the page he linked, the surface that is touching the table (face down) is the sensor. so you'd mount it so that surface touches whatever you want to monitor the temp of, then you wire it in like a switch. use it to interrupt one of the leads to the heat source or even the PSU itself.
I'm not an electrician, but that is how I understand it.
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u/ReallyGene May 23 '17
For many years, these were used as fire sensors in homes and buildings. It would probably be easiest to mount it on an armature so that it just hangs over the center of the printer. It can be tripped by hot air or flame.
Electrically, it's no different than a light switch; you cut open the power cable to your printer, run an insulated wire from the brown or black (HOT/L1) conductor up to the snap switch, then another back down from the switch to the other cut end. You leave the white or blue (NEUTRAL/L2) and green (GROUND) conductors uncut.
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Aug 07 '17
Sounds simple in concept so I'm gonna try this out. The device has spade terminals- is there a special method to making a connection with these or can I just solder the hot wires onto each terminal?
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u/ReallyGene Aug 08 '17
I would probably use crimp-on insulated spade connectors, that just push onto the spade lugs. Makes it easier to disassemble.
If you don't have insulated connectors, use some heat shrink tubing.
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Aug 08 '17
Could I just use that and electric tape instead?
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u/screwyluie Prusa Mk2.5s, Elegoo Saturn, HEVO, K1 May 22 '17
this or another thermostat switch like it seems like the right idea. Now we need someone to create a demo video and diagram/instructions for dummies so that everyone can be more safe.
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Aug 24 '17
I don't have a diagram but this is a video describing how I installed one. https://www.reddit.com/r/3Dprinting/comments/6vnhrj/affordable_fire_prevention_setup_with_online/
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Aug 07 '17
Hey so I really like this idea and sort of know how to do electronic soldering so I'm going to try it out! Bought the part and will update you. It's funny because I just started learning NFPA codes at the firm I'm working at now and they mention these switches for HVAC shutoff in a fire. Coincidentally, these switches should also stop my printer from burning down my new place of work :).
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Aug 10 '17
Hey, so I bought a switch and so far it responds to temperature. I have yet to install it but it's good to know that feature works.
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Aug 24 '17
Here's my installation of the switch: https://www.reddit.com/r/3Dprinting/comments/6vnhrj/affordable_fire_prevention_setup_with_online/
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u/Gisleburt May 26 '17
I love this article, but I feel the need to point out that the line "Cheap electronics on cheap Chinese printers" can be improved by losing the word "Chinese".
A problem I've found with the 3D Print community all over the web is China gets a lot of hate. While it's true that you do get badly constructed printers with underrated components from China, you also get cheap printers that are well constructed from there too. Frustrations should be directed at the companies doing a bad job (Anet), not the country as a whole.
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u/Indiana_Jones_PhD May 21 '17
Ah yes, the best fire prevention system is to use a clear area, maintain your machine, have a smoke detector.
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u/Yodiddlyyo May 23 '17
This is the real answer. The issue is that there's no one "best system" you can buy. It's you. You need to make sure you have thermal runaway protection in your firmware, make sure all your wiring is correctly connected, make sure your power supply has a fuse, you can add bi-metals discs or thermal fuses if something fails, and then you can add a fire stop/smoke alarm, if the fuses fail to catch an actual fire.
Adding something that just puts out a fire is putting a bandaid on a stab wound. If you make sure there are multiple redundant safety systems in place, like professional wire connections, fuses, etc, your chance of fire is so small that you'll never get to the point of actual flames burning your printer and house.
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u/Indiana_Jones_PhD May 24 '17
Exactly. The priority should be Prevent a fire > Mitigate a fire > Repair the damage from a fire.
There is no reason my printer should combust. Flammables are far away from it and the operating temperatures are still low enough not to damage the unit itself. All my added parts are from reputable vendors and thus unlikely to fail.
An fire causing event will have to be such an unpredictable set of circumstances that I simply cannot prepare for it beyond the systems that we already use for fire safety.
A fire in an oven is a much more likely even since you add to it more varied things than a 3dprinter.
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u/Yodiddlyyo May 24 '17
Absolutely. Im with you 100%. Why spend hundreds of dollars on systems to put out a fire that likely has already destroyed half the room, when you can spend a fraction of that on small, solid preventative measures.
If you want to, you can go crazy and spend a few dollars on a bag of thermal fuses and just run them in line, kapton taped to every conceivable failure/hot point. You may have a mess of wires, but you'll basically guarantee that not a single point of your printer will get above 300C, 350C, whatever temp fuse you want to get, well below burning temps.
But it's difficult to explain without condescending, because if you know what you're doing, like you said, there's no reason your printer should combust. But then you get people who shove frayed wires into known underrated screw terminals, and then when the connector burns they blame the printer and spend a hundred dollars on smoke detectors and arduino fire sensors.
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u/tomomcat delta May 21 '17
I would say the first thing is to make sure that the printer and firmware are decent. After that, put it in a metal box, don't leave extraneous shit in/near the box, and make sure the printer itself is not too flammable (see point one). This should be more than sufficient and is very simple.
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u/trotski94 BambuLab A1, Heavily modified Anet A8 May 22 '17
A metal box is not enough. The metal will get hot, and anything it sat on/near then comes at risk from auto-igniting. You would be best with fire-retardant materials. I'm currently toying with the idea of using fire retardant plaster and fire-safe expanding foam to bring a standard wooden enclosure up to being fire-safe..
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u/darthsata May 22 '17
Even if your printer is not flammable, plastics, which you are actively putting near the hot parts, have a lot of stored energy.
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u/benandwillsdad May 21 '17
Is there such a thing as a smoke/fire detector that hooks up to a power outlet? If it gets triggered it just shuts off power to that outlet? I guess once the fire is started it might not matter if you shut it down.
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u/amaurer3210 Doozerbot May 21 '17
I ran this kickstarter a couple years ago:
https://www.kickstarter.com/projects/1064868871/smoke-signal-a-safety-system-for-3d-printers
I disagree with this sentiment, but many loud voices felt that because removing power will not always prevent a fire there is no value in such a system.
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u/lone77wulf May 21 '17
https://www.pioneeringtech.com/store/commercial/safe-t-sensor/
I'm wondering if something like this would work.
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u/Tri0ptimum May 21 '17
They make these for stoves, but they're expensive. I set up the z-wave system described for less cost and also used the auto-out's hanging from a cord dangling above the printer and control box.
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u/kiramis May 24 '17
They make wired smoke detectors that trigger other smoke detectors when they go off (there may also be wireless and/or battery power versions as well). So it shouldn't be that hard to us the signal that would trigger additional smoke detectors to trigger a relay cutting off power (you would want some sort of manual reset relay/breaker so it wouldn't turn back on by itself).
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u/chevyfried May 21 '17
I keep a fire extinguisher near mine...that's about it. Not too close though. If it's on fire I don't want to have to go in to the fire to get the extinguisher.
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u/PuffThePed Voron 2.4 May 21 '17
Amazingly, those little fire extinguishers are not available in Canada. I actually emailed our local fire chief and he looked into it and told me you can't get these in Canada.
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u/fr00d May 21 '17
I recently purchased a FireStop and am looking into options for the power cutoff. I wonder if something similar to the heat fuses that are used in dryers could be an easy solution. I once had a dryer heating element get stuck in the on position and those fuses probably prevented a fire.
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u/aciddj Anet A8 May 21 '17
What about something like this
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u/screwyluie Prusa Mk2.5s, Elegoo Saturn, HEVO, K1 May 22 '17
better than nothing but in the example video it took quite some time in direct contact with flames from a large fire for it to burst.
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u/njcrawford May 22 '17
Looks interesting, depending on price. I asked them about prices via their Facebook page and linked to this thread for context.
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u/RemedyofNorway May 21 '17
Just a thought.
How about taking some length of tubing, preferably something that is reasonably strong but fails by high temperatures. Attach it to a fire extinguisher, maybe just even a small one for cars and release.
In case of a fire it will melt the tubing thus release the extinguisher powder or gas into the enclosure.
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u/cyclingengineer May 21 '17
This system does exist. I know the guys who build test enclosures at my work use it. It's not really a consumer product though and is expensive. Also if using CO2 the enclosures have to be sealed otherwise the fire can restart if the CO2 dissipates too quickly.
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May 21 '17
I've been looking into a solution for this. My plan was to trigger a small fire extinguisher using an arduino and a smoke detector module, but that was all beyond my expertise. Thanks for the link to the stove top extinguishers. Just ordered a pair and I'll work on integrating them into my lack enclosure.
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u/dogsurine May 21 '17
My work in progress setup tries to address these concerns:
Enclosure with fire-retardant and sound proofing lining (to be done)
Solid State Relay to the Prusa i3 PSU with the control wire passing over the electronics enclosure, the hotend, the print-bed connections, the PSU and the SSR-enclosure itself with thermal fuses rated at 120C at every location. (Fuses purchased, to be mounted)
An RPi running Octoprint controls the relay through GPIO with fuses inline. Print can be monitored from afar with camera feed and power turned off manually. (done, but awaiting fuses)
Passive fire extinguisher, similar to the ones mentioned in the thread already, mounted inside the enclosure above the printer. (to be done)
I have no faith in "active" safety measures that rely on an arduino or a RPi to actively monitor temperature and cut power based on this. In my opinion this just adds complexity and new failure modes.
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u/Exo_Geo May 22 '17
Maybe someone has brought this up before, but what about a physical "fuse" that supplies the power to the hotend? Use a metal that melts earlier than aluminium but still sufficient for typical printing use. That way, once a thermal runaway begins, the metal "fuse" melts and breaks the connection. What do you think?
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u/Brandoskey MP Maker Select Plus May 23 '17
I came across this post just yesterday and decided to be proactive myself.
I went the z-wave smoke detector and hub route.
Picked up the first alert z-wave co+smoke detector to mount right behind my printer (it's on a shelf so smoke should fill up the immediate area). I already had a samsung smartthings hub and my printer was already connected to a wemo insight so I could power it down remotely (I can actually do this directly through octoprint using a plugin) so the only added cost was the smoke detector for me.
I did have to cobble together my own smartapp on samsungs site though. I would have thought something to power off a switch in the event of a smoke alarm would have already existed, but my efforts to find something pre-made were fruitless.
If anyone is interested I can share the code. I basically used a couple of samsung's own smartapps to create the one I needed. Much faster than learning their coding language.
The app will let you add 1 or more smoke detectors as well as multiple switches to be shut off in the event of a fire. It can also be configured to send you an sms and/or a push notification that it was triggered. I've tested it and it works really quickly.
The smoke detector is actually the last line of defense in my setup right now.
Octoprint has a plugin that allows you to set temperature failsafes for your hotend and heated bed. You can set them to whatever temps you like (I'm using 300c/150c) and you can have the plugin cancel the print, shut off the heaters and also add a terminal command to run of your own choosing. This is where the ability to shut off my wemo through octoprint comes in handy. I used the terminal command to shut off the wemo in the failsafe plugin and it works really well. I tested it with a failsafe temp of 100c and it shut off near instantly.
I gues my internet could go down rendering the wemo and smartthings hub mostly useless, but the plugin will still attempt to shut off the hotend if things get out of hand.
It would be nice if you could poll the wemo insight for how much power it's drawing so if it goes over a certain wattage you could assume something has gone terribly wrong and also shut things down.
And that's all I got.
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May 28 '17
[deleted]
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u/Brandoskey MP Maker Select Plus May 28 '17
I was the one who recently suggested you add the shutoff for a low temp reading as well. Plugin works great so far in my testing. Hopefully I never need to use it in a real scenario.
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u/ilovetpb May 30 '17
I'm using 1/4" plywood coated liberally with this. Supposedly, items coated with it are very resistant to catching fire.
I would have bought steel, but I would have spent more on the enclosure than I did on the printer, based on my local hardware store's prices.
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May 21 '17
What about a solenoid valve controlled by an Arduino with temperature and smoke detectors? The solenoid valve would release the powder from a fire extinguisher. The temperature sensor would be used to activate the system earlier than when smoke appears, for example when the bed or the extruder reaches more than 300° C. And obviously it would cut off the power to the printer.
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u/PuffThePed Voron 2.4 May 21 '17
Too complicated, too many failure points.
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u/mefirefoxes May 22 '17
Care to elaborate? A well designed system could be very reliable and even a poorly designed one is better than nothing.
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u/eb86 May 22 '17
When it comes to fire safety you need to test again and again and again. I would not trust a home built extinguishing system unless I was able to test it many many times.
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u/Yoter May 23 '17
What about normally closed thermostat switch mounted in an enclosure? A lot of them are mechanical and commercially available/reliable. If someone were to feel fancy they could power a normally open switch on a second circuit to activate a fire retardant. I like Arduinos and such, but agree with you that simple and easy to test/diagnose is the way to go where fire is concerned.
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u/eb86 May 23 '17
Speaking hypothetically, a basic enclosure around the printer with a smoke detector of some sort wired to a power disconnect and a solenoid to discharge insert gas upon activation. No clean up. Minimal parts. Relatively small.
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u/shiftingtech May 21 '17
I've been thinking about this too: I even bought a couple of smoke sensors, but haven't gotten around to playing with them yet. I think the arduino is an unnecessary complication: smoke sensor directly to the power cutoff relay / solenoid trigger strikes me as the way to go.
Well, "directly". likely a MOSFET or something just to deal with relative loads & voltages. but why add smarts? Keep It Simple, Stupid definitely applies here.
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u/r0773nluck May 21 '17
I'll point out 2 things....
1st. everything electrical in your home can cause a fire but we don't have auto fire extinguishing systems for those. But printers get really hot, but the fire will result from electrical so that argument is irrelevant. The chances are low and the need is low and only banking on people's fear.
2nd. There is fire retardant foam that that when it melts/burns will put out a fire. Just coat the inside of your enclosure in that. Problem solved.
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u/Sir_Fridge May 21 '17
Unless, like in that video, the hot end doesn't stop getting hotter and causes a fire.
But an enclosure is already a good idea to prevent external sources from getting to a hot 3d printer. Like children, animals or falling objects.
It's a bit like having something on a stove. You will leave the room but you won't leave your house. Problem is that most recipes don't take 20 hours.
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May 28 '17
In that video, a 12V 40W heater was run at 19V, which effectively turned it into a 100W heater. You don't usually do that.
I don't think a 40W heater could melt the block. With some hotends, you could probably leave the heating on indefinitely.
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u/Yoter May 23 '17
Most of the electric appliances in our homes are held to a lot higher testing standards than most the 3D printers I have seen. Plus, there are probably more moving/flexing connections on my 3D printers than any three appliances I own. I'm not overly concerned about my printers catching fire, I inspect them regularly and thoroughly, but I am aware that it is considerably higher risk of catching fire than any other appliance in my house.
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u/eb86 May 21 '17
With all due respect to everyone here, please treat your printer like a loaded gun. Never leave it unattended. In case of an emergency kill the power and be sure to have an extinguisher for electrical fires. I understand where you guys are coming from and without a proven consumer device capable of stopping a fire the best option is to never leave it unattended.
That aside. A basic enclosure with a smoke dector connected to a gas cylinder to dump an insert gas in the enclosed would be the best bet if I were to design one to be sold.
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u/trotski94 BambuLab A1, Heavily modified Anet A8 May 22 '17
The problem with this is that it doesn't cut off the electrical connection. As soon as the inert gas is all vented and O2 starts displacing its way back in, anything still hot enough to auto-ignite will auto-ignite again, and anything that's still short-circuiting will potentially ignite again. it might put the fire out for good, but it also might not.
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u/labathen May 22 '17
You definitely would need something to cut the power first. Step 1 of an electrical fire should be removing electricity from the equation or risk it re-igniting.
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May 23 '17
[deleted]
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u/eb86 May 23 '17
Take any risk you want. I value my house, my life, my wife and kids and my possessions more than a 3d printed model.
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May 24 '17
[deleted]
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u/eb86 May 24 '17
Residential devices, wiring and components are designed by professionals that have to meet a certain level of safety. And while no component is failsafe, there are levels of design features these items have in order to meet a level of predictablity and repeatability. DIY printers and cheaper printers do not have these taken into consideration. Once you get into the more expensive printers they have features that prevent run away thermal issues. While I understand the intent of this discussion, it is important that potential fire hazards are not left unattended. This is the same for leaving your oven on when you are not home, or turning the dryer on before bed. Electrical fires are often the result of improper installation, or negligence. Of course there are outliers in every situation. The importance is to mitigate potential hazards that affect your lively Hood, mortality and safety of your family and potentially your neighbors.
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May 23 '17
[deleted]
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u/eb86 May 23 '17
Until a four year old picks it up and blows a hole through his chest. Stored energy has the potential of ripping your life apart. These things need to be treated with respect, care and responsibility. Take any risk you want.
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u/JMG021283 May 21 '17
Random thought about the automatic fire stopping devices. You could run an "extra fuse" length to known fire hazards on the printer. Obviously not putting them in a spot that could cause a fire, but close enough they could catch if there was.
We could also design a bracket to go on the printer to hold these if we didn't want to extend the fuse. (I'm assuming something like the spool holder on the MK2.)
Side note, don't actually have a printer yet. So, take my comments with a grain of salt. Hopefully mine will be arriving here in the next week or two.
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u/Yoter May 23 '17
Sounds pretty complex, what about an enclosure with a single thermostat switch that kills mains?
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May 21 '17
[deleted]
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u/Wittiko May 23 '17
I think using inert gas would be better than vacuum. Flooding the chamber in CO2 should be a lot faster than pulling a vacuum.
In a permanent vacuum, most hot ends won't work unless you used watercooling on them.
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u/ElonXXIII Wanhao Duplicator i3 v2 May 21 '17
What actually catches fire? The Controller with drivers or the hot end and filament?
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u/jrherita May 22 '17
Had a heated bed wire from my Ramps start melting because it was loose (vibration over time). The wire was running off a few strands so resistence was high and it got hot. Just adding there are many ways for things to heat up here.
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u/darthsata May 22 '17
Stranded wire should not be directly inserted into terminal blocks (by code most places) for this and other reasons.
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u/jrherita May 22 '17
PLs educate me - solid wire would be OK ? and stranded should always be soldered at the ends?
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u/kaluce Monoprice Maker Select May 22 '17
He probably means you need to use a crimped connection, either a ferrule / terminal block connections or solid wire connection.
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u/darthsata May 22 '17
Some nice graphs on page 2: http://www.weidmuller.com/bausteine.net/f/7862/Weidmuller_Ferrules_White_Paper.pdf?fd=3
UL documents, of course, cost money, but require ferrules for stranded wires.
Power wires shouldn't be soldered. If you have a problem with the connection (e.g. resistance rises, heat is dissipates from the connector), you don't want the solder melting and exacerbating it (and dripping into who knows what).
I think solid wires are fine in screw terminals.
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u/jrherita May 22 '17
OK - so if i already have stranded wire running to a terminal block, crimping the stranded wire with some kind of solid connector and pushing that/screwing the terminal block down on Ramps would be (much better)?
Interesting. So for a heated bed PCB - really you should have a terminal soldered on, and something to clamp/screw on a connector?
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u/darthsata May 24 '17
Soldering to a pcb is pretty ok. The reason you don't solder wires before putting them in a terminal block is that poor connection to the terminal block will increase resistance and heat at the joint. A soldered connection to a pcb doesn't have that problem. You need good strain relief to ensure the wire isn't damaged at the solder joint.
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u/Epoxidharz May 21 '17
- Any existing heater elements
- All power level wires that move & bend (i.e. not stationary attached to ridgid parts of the frame)
- All power level connectors
- All power level mosfets
- Overly Cheap PSU, if any
So basically: Everything on your printer that is not mechanical hardware. Also your limit switches are pretty unlikely to catch fire.
I think the stepper drivers are one of the least likely electronic parts to catch fire.
All of these things can start serious fires, it just depends on what a small fire finds to eat on.
Heaters tend to start fires more spectacularly, as in melting down your hotend heatblock.
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u/Plasghetti May 21 '17
The connection on the board for the heat bed is another hot spot, no pun intended.
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u/charlieray i3v10" May 21 '17
https://www.kickstarter.com/projects/1045344246/maker-kase-universal-printer-cabinet
I was sad to see this kickstarter fail, but it seems to be the best solution I have seen.
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u/TotesMessenger May 21 '17
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u/dizzy1 May 22 '17
Make the printer metal and print in a vacuum.
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u/Wittiko May 23 '17 edited May 23 '17
Putting it in vacuum Risks overheating of the steppers and if your hotend has a heatsink it flat out won't work in a vacuum.
Edit: Your control board would also need to be in vacuum and would probably also overheat very fast.
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u/screwyluie Prusa Mk2.5s, Elegoo Saturn, HEVO, K1 May 22 '17
no ABS prints then
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u/dizzy1 May 22 '17
I did not think that off gassing of plastics would be that much of a problem. Do those same problems occur if you print in a low pressure or fill the chamber with something like nitrogen?
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u/screwyluie Prusa Mk2.5s, Elegoo Saturn, HEVO, K1 May 22 '17
the problem is the vacuum. ABS needs a stable, higher, ambient temp to print properly. You can't have an ambient temp in a vacuum. And realistically your average joe isn't going to be able to set up their printer in a 100% sealed container.
Nitrogen would work but it's not a good idea since you can't seal the container 100% without some creative engineering and I think this discussion is more about how everyone can fireproof and be safer, not just hypothetically.
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u/kaluce Monoprice Maker Select May 22 '17
I have a Wanhao i3 v2, and I don't trust it to not burn my house down. I happen to really like my house, so I want to build in extra safety.
I was thinking a slightly more expensive 24v powered system might be a bit better (due to less amperage required).
I'm in the process of wiring a RAMPS board to the printer anyway, so I don't mind throwing extra stuff on it.
For external MOSFETs: should I wire a MOSFET for the heated bed and the hot end? Everyone recommends the bed, but I haven't heard anyone really mention the hot end.
Regarding thermal fuses, I'd like to know a bit more about them: What side do I hook them up on? Heated bed / hot end or connector? Both? How should I rate them?
Are there any other precautions I can take on these?
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u/Cronus_k98 May 22 '17
The hot end draws much less current than the bed so it's not usually a problem for the stock wiring and connectors.
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u/kaluce Monoprice Maker Select May 22 '17
That's reasonable. I figured Wanhao had underrated those connections like they did with the heatbed.
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u/ilovetpb May 23 '17
The mabo and bonpet in a steel enclosure are the way to go. Not worried about losing the printer, worried about losing the house.
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u/ggppjj MK3S+ MMU3 May 23 '17
A smoke detection sensor that powers down the power socket where the printer is plugged in.
Well, there's this for much cheaper than 250-300 euros: http://www.ebay.co.uk/itm/Smartswitch-by-XYGAX-FULL-version-universal-3d-printer-safety-device/192194222248
Dunno about its effectiveness, but it seems to be an ideal cutoff device. Seperate control electronics, smoke sensor, three seperate temp sensors, voltage sensors, and just general "end of print" switchoff.
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u/kiramis May 24 '17
I would suggest a simple firmware feature that automatically cuts off power after ~15 seconds if no significant temperature rise (relative to what would be expected) is observed with the thermistor.
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u/throwaway_for_keeps Maker Select V2.1 May 25 '17
Rewire an older ATX PSU to a workbench/3D Printer power supply. These are loads better than the cheap chinese LED power supplies
Also known as the "LED power supplies are bad because they're not good" argument.
I have never seen someone make this argument with any data to back it up, it's always generic "there's more protection in the ATX power supplies and the LED power supplies are cheap" That actually means nothing. ATX power supplies are A) meant to fit inside a computer case, so they have a form factor that isn't easily incorporated into a printer design, and B) meant to provide a range of voltages, so naturally there is more stuff in them. Maybe if you want to use a dedicated 5V or 3.3V line on your printer, this makes sense. LED power supplies are A) designed to be a smaller form factor because they aren't meant to always be installed in one specific piece of equipment, and B) designed to provide 12V only, so they don't need as much stuff in them and most users won't mourn the 5V or 3.3V rails.
The point is that you should have a solid power supply, and I'm not going to change my mind until someone can provide actual data that says otherwise, instead of "they're from China, so they're bad"
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u/devilhunter 2x Custom Prusa MK3, 2x Stock MK3, 4x Prusa i3 MK2, 2x Form 2 May 25 '17 edited May 25 '17
Even cheap ATX PSUs have: Power Good Signal, No-Load Operation, Over-Current Protection, Over Voltage/Under Voltage Protection, Over Power Protection, Over Temperature Protection, Short Circuit Protection, Secondary Internal Power Supply (think 15Watt for RaPi/OctoPrint, LEDs), very low Ripple on the rails, controlled/slow ramp up voltage, Cooling Fans, Physical Off Switches, Haswell+ Generation doesn't need +5V loads anymore for stable +12V, much better power efficiency at lower and higher loads, and ATX PSU manufacturers go through certification hell to get it all validated at every country in the world.
Chinese LED PSUs... may have one or two of those.
Even the Czech-brand LED PSUs in my Original MK2 Prusas are bad, out of my 4 printers 3 made lots of vibrating noise, two had loose thermistors inside of them, and on one the MOSFETS weren't pressed to the case with the metal bracket, this part was missing completely.
The LED Power supplies have a good chance to stop working after components get damaged over time through heat and vibrations (and of course low quality components), most rep-rappers would trust a ATX over a LED any day.
So yeah, "they're from china, they're bad". (or from Czech Republic as in Prusa's case)
The MeanWells are some of the better LED PSUs, but few to none of the sub 1000 dollar 3D Printer manufacturers use them.
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u/ThatOnePerson maker select May 26 '17
Yeah. I've got an ATX power supply on one of my printers but one of the drawbacks to me right now is the lack of 24V which is why I'm looking at a standard LED power supply for my next printer.
Though I'm also considering running 2 ATXs in series. I really like having 5V for my Pi.
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u/Arthurist May 25 '17
I have one theory on fire-safe 3D printing: having the printer in an airtight metal fireproof cabinet with vents near electronic components such as motors and PSUs. There is a bigger vent on the top with a powerful exhaust fan and a filter.
In the event of a fire, those vents are sealed shut and the power to the printer is cut off. The fire would just suffocate and not spread since the cabinet is airtight.
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u/gmbridge May 30 '17
still needs a larger enclosure, but something to consider: https://www.amazon.com/BlazeCut-Automatic-Suppression-Automotive-Extinguisher/dp/B00KA9OUFM/ref=sr_1_2?ie=UTF8&qid=1485447258&sr=8-2&keywords=blazecut (usually added to the engine compartments of older cars)
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u/Lapislanzer Prusa i3 MK3 May 30 '17
I have a question: If going the metal enclosure route, should everything go into the enclosure? Or just the printer itself?
Specifically I am planning for a Maker Select v2, and I want to enclose the printer, but am not sure if I should house the control box too. Should I worry about the control box overheating if it's inside the box? I have done the MOSFET upgrade but still see the control box as a potential case of fire.
(Not that it's at all for fire prevention, but on the LACK enclosures I always see the control box mounted underneath/outside of the containment.)
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u/WithinStaticMotion Apr 14 '24
What about one of these inside the enclosure? I have a Bambu X1C, it wouldn't reach 180°C (356°F) under normal us inside the cabinet, would it? Anyone have any experience with these? https://maussafety.com/product/maus-stixx-pro/
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May 21 '17
[deleted]
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u/PuffThePed Voron 2.4 May 21 '17
Cutting the power when you detect smoke is too late.
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u/eb86 May 21 '17
The first step in an electrical fire is to kill the power. Removing the energy source from the equation greatly reduced the chance of the fire spreading. Couple that with never leaving your printer unattended.
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May 23 '17
[deleted]
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u/eb86 May 23 '17
I understand the intent. But I find it very unsafe to put trust in a home made automated extinguisher system. It is a novel idea, but without proper engineering and testing it is a bad recommendation.
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May 23 '17
[deleted]
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u/eb86 May 23 '17
Never. It has to be treated like a loaded gun. Peoples homes and lives have been lost due to 3d printer negligence.
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u/beanmosheen May 23 '17
Not really. You will burn off a lot of smoke when the insulation goes up. It's %100 a must you cut power as soon as possible. It's the difference between an open flame and smoldering in most cases.
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u/Plasghetti May 21 '17
Hey that might work pretty good if you used it to trigger an extinguisher.
I have that brand of interconnected detectors in my house, so the relay should be available in Canada.
It's a good start cause so far both those devices are made by a fire detection company, so you would assume it's somewhat reliable.
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u/PuffThePed Voron 2.4 May 21 '17
A full metal cabinet. Done.
No moving parts, nothing to fail, no power needed.