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filament run out in the middle of night - fire?  

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bob.h7
(@bob-h7)
Eminent Member
filament run out in the middle of night - fire?

I am doing an experimental print (nut and bolt - separate pieces). The Mk3 will probably run out of filament while I sleep.
Assuming the filament sensor and all other features of the Mk3 work properly, what will happen?
1. Will the very end of the filament come off the reel? It is the Prusa silver/grey that came with the Mk3 kit. The nub end is bent at a very short 90 and stuck in a small hole on the side of the reel.
2. How will that very short 90 piece slide through the filament sensor cover and PTFE tube to get to the filament sensor so it can do its job?
3. Assuming the filament gets to the sensor, what will happen? How long will the bed & nozzle stay heated? Is it a fire hazard?

Many thanks.

Posted : 10/01/2019 4:10 am
toaf
 toaf
(@toaf)
Noble Member
Re: filament run out in the middle of night - fire?

odds say it will just sit there beeping like an ass.

I think it stops heating. small chance the heatbed stays on. I wouldn't worry about that.

I have a Prusa,therefore I research.

Posted : 10/01/2019 4:32 am
stahlfabrik
(@stahlfabrik)
Honorable Member
Re: filament run out in the middle of night - fire?

Why should it cause a fire when filament runs out? And why shouldn't it cause a fire while printing?

You should not let your printer run unattended, that is what the manual says, that is what your insurance company will tell (if your house burns down).

Failure is always an option. 🙂

Posted : 10/01/2019 10:33 am
bob.h7
(@bob-h7)
Eminent Member
Topic starter answered:
Re: filament run out in the middle of night - fire?

Does Prusa intend that anchor nub to go through the sensor cover?
Should I try to get to it and clip it off before it gets stuck in the ptfe tube and crushes it as the gears continue to pull the filament?
Does the machine shut off after x hours of no response to the 'out of filament beeping?

Posted : 10/01/2019 12:49 pm
zoltanf
(@zoltanf)
Eminent Member
Re: filament run out in the middle of night - fire?

It will beep (if the sound is on in the settings) and it will stop heating the hot end after some time (I think it's 20-30 minutes). The bead will keep the last set temperature.

The message on the LCD will change to "Press knob to heat up" or similar. You press that, it will heat up to the desired temperature. Wait a bit before unloading the filament, then unload and put in the new one, after that it will extrude some and will continue the print.

I never run out of filament but I did left it overnight with a filament change scheduled on a layer, the behaviour is similar.

Posted : 10/01/2019 1:31 pm
Fotoman
(@fotoman)
Trusted Member
Re: filament run out in the middle of night - fire?

I had a filiment sensor fail and support chat told me it was probably because the hook at the end of the filiment went through and damaged the sensor. At the time I had not seen the hook and was unaware it was there.

I dont let that happen any more. I make sure I am around when the hook gets exposed and cut it off with a pair of wire cutters. Then the rest of the filiment runs through with no problems.

If this is the case and the sensor can be damaged by the hook, I think it should be mentioned somewhere in the liturature for the printer. It talks about filiment running out as one of the benifits of the sensor, and I personally have only ever had the filiment run out at the end of a spool where the hook is. I understand it is possible for the filimet to break but... Anyway a warning or caution would be nice.

Proud owner of a Mk3 that is producing very nice prints. There is room for improvement as I learn more about it, but so far I am very happy.

Posted : 10/01/2019 6:09 pm
stahlfabrik
(@stahlfabrik)
Honorable Member
Re: filament run out in the middle of night - fire?

So that would indicate that indirect filament sensor mods are really a good idea:-)

Posted : 11/01/2019 12:53 pm
DaveGadgeteer
(@davegadgeteer)
Eminent Member
RE: filament run out in the middle of night - fire?

It's really hard/impossible to fix this perennial problem ahead of time. Something needs to monitor it while I'm asleep...

How about a guillotine that is triggered when the fiber end shows up, and cuts it off cleanly. Something like a spring mouse trap where the fiber prevents something falling on the trigger?

That would allow end-of-spool to be handled nicely, as the printer can do if the fiber is not kinked at the end.

Posted : 29/01/2022 6:20 pm
dstarr3
(@dstarr3)
Active Member
RE: filament run out in the middle of night - fire?

I think the worst case scenarios here, while both being very unlikely, are either there's a jam that the printer doesn't detect or the filament runs out and the printer doesn't detect that. In either case, the machine will simply continue printing without actually extruding any filament. The result is a failed print, but not much else. There's no increased fire risk beyond the risk associated with 3D printer functioning normally.

The end of the filament should come off the spool just fine, and the little crook at the end shouldn't cause any issues. Issues here are unlikely, but if there are any issues here, the printer will most likely detect a jam and stop printing/heating. Worst case, it'll jam, not detect the jam, and keep printing. But like I stated earlier, this will just result in a failed print. A printer running while empty isn't any more dangerous than a properly functioning 3D printer.

The printer again should detect the end of the filament and pause printing/heating until you manually go through the filament-reloading process, at which point it will reheat and resume the print. Worst case, it'll run out and not detect it, and keep printing. Again, failed print, but no more dangerous than a properly functioning 3D printer.

Posted : 30/01/2022 2:41 am
Gilfanon
(@gilfanon)
New Member
RE: filament run out in the middle of night - fire?

I've had my Mk3s+ for a few months now and have misjudged overnight prints twice and run out of filament. I can confirm the thing beeps at a volume sufficient to wake up a 6 year old (and very grumpy as a result) girl through 2 doors and around 15 metres away at 4am in the morning... Not great. Sounds like there's a setting to switch this off?

Both times the filament ran out it was a massive PITA to change the spool - using the menu option that pops up to extract the filament and re-load did not work, and I ended up having to cancel the print so I could access the main menu, then open up the housing, disable the runout sensor and shove the last fragment of filament through before I could autoload the filament. Am I doing something wrong?

What's the best way to do a filament change midway through a long print if you know ahead of time you're going to run out? Someone mentioned scheduling a filament change - is this something you can do in PrusaSlicer?

Posted : 01/03/2022 11:05 am
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