Random filament change
Printing an object that only uses ONE tool. During the print my 5 tool XL pauses and says it wants to change filament. The filament path is fine.
Bug? Using the latest FW… 6.1.
RE: Random filament change
I had this in the very beginning when I was still dialling in filaments. Turned out I had a small filament string that had worked itself into the spring, blocking the sensor in the toolhead.
I think I printed too hot for a while and when unloading it was dragging some wisps of filament into the PTFE. Then when you load again it clings to the filament and gets pushed forward, balling up in the toolhead. I couldn't see it inside the PTFE against the background of the actual filament.
Check if the problem travels when you use a different tool.
RE: Random filament change
I think you may be correct. I turned off the setting “stuck filament detection” and it stopped doing it. That tells me it’s the sensor in the tool head not on the side… although since it’s a presence sensor vs a movement sensor I don’t see how.
Regardless, I’ll need to tear the tool down. As I wrote in another thread where another tools sensor was stuck on, there’s no well defined Prusa written procedure for cleaning the tool sensor or the feeder gear and taking it all apart is a real tricky PITA. They did not design it for regular maintenance even though regular maintenance is required!
Anyone reading this and facing a tool tear down… Make sure to keep the planetary gear subassembly together after removing the three bolts! Be super careful removing the sensor with a small needle nose pliers. Parts can fall out and get lost. Also, be sure to reinsert the sensor with the tab inwards to the hole or it won’t work.
RE: Random filament change
I guess you know https://help.prusa3d.com/article/filament-sensor-mk4-mk3-9-xl_465702
A clear warning not to take it apart on the XL but also no alternative offered 🤣
Compressed air and fiddling around with a needle did it for me. If it's strings you'll eventually catch them and manage to pull them out.
RE: Random filament change
Yes I saw that. Actually it’s just as tricky a tear down for the mk4 as it is for the XL. What would have helped is if they had two small screws going the other way on the planetary gear assembly to hold it all together so when removed it would be way easier, but that would add production cost.
Cleaning out the feeder subsystem is something no doubt every user will eventually need to do so they will have to deal with this at some point.