Prints randomly force a filament change mid-print
 
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captchemo
(@captchemo)
New Member
Prints randomly force a filament change mid-print

Recently my prints are randomly stopping and forcing a filament change.  It does it at random times, but usually early in the print.  Sometimes only once, sometimes multiple times.  Is there a filament or extrusion issue that would cause this, or is a software issue?  Anyone experiencing this problem?

Posted : 21/11/2020 10:39 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Prints randomly force a filament change mid-print
Posted by: @captchemo

Recently my prints are randomly stopping and forcing a filament change.  It does it at random times, but usually early in the print.  Sometimes only once, sometimes multiple times.  Is there a filament or extrusion issue that would cause this, or is a software issue?  Anyone experiencing this problem?

Which printer and which slicer do you use? Filament changes normally only take place if they are triggered by the gcode file.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.

Posted : 21/11/2020 11:49 pm
cwbullet
(@cwbullet)
Member
RE: Prints randomly force a filament change mid-print

Keep looking and you will find a trend.  Nothing is random.  If it is random, look at your wiring.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 21/11/2020 11:50 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Prints randomly force a filament change mid-print

Dodgy filament detection sensors also cause this issue.  If it detects no filament for a fraction of a second (problems with wiring, problems with switch etc) then it goes through the unload/load procedure.

I had it on my cr10s, the little microswitch it uses for runout detection stopped working reliably, I replaced it and no more problems.

Before I changed the extruder to a Bunny & Bear geared on on my Mk3 it also occasionally did it if the sensor wasn't cleaned out of filament dust.  Since the update that isnt a problem.

Posted : 22/11/2020 12:18 am
cwbullet
(@cwbullet)
Member
RE: Prints randomly force a filament change mid-print

@neophyl

I have two minis and each has an issue with the filament sensor.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 22/11/2020 12:21 am
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Prints randomly force a filament change mid-print

@cwbullet

On my Mini the original Prusa sensor didn't work either, that means the signal was inverted and wanted to print only without filament. For this reason I built my own construction and inverted the sensor signal. It's funny, because the sensor works with other people. But what the heck, mine works now and is even equipped with a control LED.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.

Posted : 22/11/2020 12:40 am
cwbullet
(@cwbullet)
Member
RE: Prints randomly force a filament change mid-print

@karl-herbert

Same issue here.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 22/11/2020 12:59 am
fuchsr
(@fuchsr)
Famed Member
RE: Prints randomly force a filament change mid-print

Filament sensor. I've had this happen a few times. One way to check is to set filament sensor action in the settings menu to continue. If that ends the behavior you know where to look.

 

Here's the troubleshooting site:

https://help.prusa3d.com/en/article/ir-filament-sensor-troubleshooting-mk2-5s-mk3s_112226

 

Posted : 22/11/2020 12:16 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Prints randomly force a filament change mid-print

@fuchsr

Yes, the Prusa Mini Sensor is also a hybrid version. It switches the contact through when filament is inserted but the firmware interprets this as not present. To check the switching process I installed a LED. I changed the Mini firmware to invert the signal. After the firmware change the Mini now detects existing or leaking filament correctly.
Anyway, it runs now.

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.

Posted : 22/11/2020 3:12 pm
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