Halt and catch fire?  

RE: Halt and catch fire?

I recall only once incident in the last year and a half with a Prusa machine, and the official conclusion (IIRC, they took it VERY seriously) was that the printer had been modified by the user. Alas, I cannot recall specifics as to how it had been modified, but I'm guessing it was more than just "change the fan duct for a different colour". Probably one of the contributing reasons the Mini has the appendix for non-factory firmware now.

Generally speaking, there is an elevated risk. Most household appliances with plastics in proximity to heaters (coffee makers, etc) have fire retardants in the plastic that mean once the source of heat is gone the flames will self extinguish, and thermal fuses to prevent them overheating.

Printers, on the other hand, are often made with 3d printed parts, which do not have those additives. Plastics are essentially just solid hydrocarbons, and most will burn quite readily once ignited.

The parts are in close proximity to a heater that, if powered without regulation, can get very hot - and the safety is all in software; there is no mechanical temperature cutout or thermal fuse that opens in the event of something like a MOSFET shorting (where the board can no longer control the heater and it is permanently on) or the board freezing while the heater is on. These are relatively cheap parts, and it's a little surprising there isn't one attached to the heat blocks of higher-end printers. 

There have been documented incidents in the past where either poor quality control (fake heatbed connectors) or firmware (some manufacturers disable thermal runaway detection!!) has resulted in printers catching fire and igniting people's workspaces, exactly via the mechanisms above- the ABS fan shroud catches fire and ignites the rest of the extrude, which, in turn.... well, burning plastic can be a lot like napalm; it spatters burning droplets of itself, which will fall and stick to/ignite other things.

And woe is you if you keep your IPA and acetone near your printer in such a scenario... things can get ugly very fast.

I don't run my printer unless I'm home and awake -  and when I am ready to make the leap, I have a smoke alarm with a trouble output line I intend to wire to a control box to kill power if there are any signs of trouble.

RE: Halt and catch fire?

Posted by: @vintagepc

And woe is you if you keep your IPA and acetone near your printer in such a scenario... things can get ugly very fast.

Uh, this is actually very embarrassing!  🙁

I'm sure that I'm not the only guilty party.  Needless to say those have been swiftly relocated.

As I mentioned in another thread, I have the 3d Upfitters enclosure on order, and I was thinking of putting a smoke detector inside of it.  I like the idea of taking the output of it and using it to kill the power, and I'm going to look for a detector that has such an output.  I'm also planning to have a Pi Zero monitor the enclosure temperature, and this can also kill the power should that temperature get out of bounds.

RE: Halt and catch fire?

I've heard of one Prusa MK2 catching fire (but this was due to the user modding it incorrectly), and about three or four non Prusa printers going up in flames.  Most of them were down to users not maintaining them or modding them incorrectly.

RE: Halt and catch fire?

I think Angus from Maker's Muse had an incident with being shocked that was finally determined not to be the fault of the printer. There have been a handful of reports of thermal runaway and some pics here, though I think most were limited to charred controller boards and melted connectors. Things that might trigger a smoke alarm, but not full fires.

My understanding is that thermal runaway protection will protect against some of the most common hardware failures, but if the controller itself is faulty, things can still go wrong as @vintagepc notes. Prusa's use of quality components certainly helps (fire resistant electronic components, fuses) compared to other brands. Creality shipped a bunch of printers with faulty connectors (XT60?) last year IIRC. Even with thermal runaway enabled, there were a lot of smoking connector issues at the time (since remedied).

The bigger concern for me is how homeowner's insurance would view things if something does go wrong. Does using an unlisted product in "unsafe" (or at least uncontrolled) circumstances void insurance coverage?

RE: Halt and catch fire?

Hint: You want to look for AC-wired smoke detectors that can be linked - they have an output that is connected so that if one alarm sounds, they all sound. 

This output is normally 9VAC. Just be wary of more modern non-conventional ones that may actually use some sort of protocol to indicate more than just an alarm condition. For example, combo alarms will typically have a special way of communicating a CO alarm vs a fire alarm. 

RE: Halt and catch fire?

Posted by: @jsw

Here's a question, specifically pertaining to original Prusa printers, brought on by another thread having to do with unattended printing.

Has anyone personally had, or have first-hand knowledge of, a 3d printer, specifically a Prusa printer, actually catching fire or causing a fire?

Yeah, everyone's seen those photos on the Interwebs, but in reality, how common are 3d printer fires?  Is there any evidence that 3d printers are more of a fire hazard than common household appliances such as stoves, ovens, waffle irons, deep fryers, electric irons, dryers, (soldering irons) etc?

I'm not talking about some stinky smoke coming out of a power supply before the fuse/breaker/crowbar trips, I'm talking about any incidents where a (Prusa in particular) 3d printer caused combustible material, on the printer or near, to actually ignite and spread, as in a typical Class A or B fire?

Yes.  I have had one caused by stupidity and one near miss and fried cotroller board caused by a loose wire on the heat bed.   

It is rare, but I recommend not printing unless you are at home.  

RE: Halt and catch fire?

I saw this and thought about buying one.  

https://www.tindie.com/products/niujl123/smoke-alarm-for-3d-printer/

RE: Halt and catch fire?

Posted by: @charles-h13

I saw this and thought about buying one.  

https://www.tindie.com/products/niujl123/smoke-alarm-for-3d-printer/

I actually bought one of those. Haven't installed it yet. It's a self-contained solution, but doesn't readily link to anything external if that's what you ultimately want.

RE: Halt and catch fire?

Posted by: @bobstro

Posted by: @charles-h13

I saw this and thought about buying one.  

https://www.tindie.com/products/niujl123/smoke-alarm-for-3d-printer/

I actually bought one of those. Haven't installed it yet. It's a self-contained solution, but doesn't readily link to anything external if that's what you ultimately want.

Jeez, the shipping adds close to 50% to the price!

RE: Halt and catch fire?

@jsw

It's a BIT less if you buy through PandaPi.

RE: Halt and catch fire?

Posted by: @holmes4

@jsw

It's a BIT less if you buy through PandaPi.

What is a PandaPi?

RE: Halt and catch fire?

I found the $45 price with shipping competitive with other pre-built solutions. Cheapest , of course, is to roll your own. I wanted to support the guy who built this solution for the rest of us.

RE: Halt and catch fire?

Posted by: @charles-h13

Posted by: @holmes4

@jsw

It's a BIT less if you buy through PandaPi.

What is a PandaPi?

Looks like a company that makes Raspberry Pi based 3d print controllers.

RE: Halt and catch fire?

If you go to the link posted above, the page says that the product is also sold through PandaPi and a link is given. It saved me $2.

RE: Halt and catch fire?

RE: Halt and catch fire?

$40 is cheap compared to the loss of a workshop or home.  

Posted by: @wink7887

RE: Halt and catch fire?

Wink, did that cause any actual fire, as in combustion of nearby flammable material, or just smoke, stink, damaged electronics and maybe a bruised ego?

RE: Halt and catch fire?

It was an actual fire, a flame actually formed when I approached it.  Good timing on my part and a lot of luck

RE: Halt and catch fire?

I installed a regular fire alarm on the ceiling on top of the printer and have a fire distinguisher not far away for my electronics bench.

@jsw (Uh, this is actually very embarrassing!  🙁) Hmmm you are not alone and I just relocated my IPA bottle too on reading this........