End of filament handling
A couple days into printing with my Mk4 (upgraded from Mk3 several days ago, all seems to be working fine). Ran into an odd handling of when the filament hit the end of the spool. The printer sensed the end of the filament fine, started beeping, and asked for me to remove the filament from the extruder.
The end of the filament was down inside the top hole, so no way to grab it and pull out the remaining short bit. Seems like it should have reversed the drive like it does when doing a normal unload, but I'm wondering if the end of the filament jammed on the edge of the hole maybe?
No way to tell it to try unloading again, so I opened the latch on the side of the head to get at the filament, was able to grab the side of it with some tweezers and pull it free. The problem came when I closed and latched the follower though, the print head moved sideways on the x axis when I pressed on the latch. The printer then prompted me to load the new filament and continue printing, which I did. Hoping it would notice the move and re-home the x axis, I watched closely and all it did was move back to where it left off on the print, and started printing assuming I had not made the move - now it was 1/4" to the side, printing in midair, so I had to cancel the print and start it all over with about an hour of printing lost.
So - it seems to me that the filament path is either not able to back out the last piece when at the end of the spool, or it didn't try, I don't know since I was not watching what happened. On my Mk3 it always handled this case fine. Also, is there a wy it could have noticed the move of the X axis that happened as I re-latched, and re-homed it against the side like at start of print? Or have a menu option to tell it to do that?
Chris
Very often the bitter end of the filament has a distinct bend or kink fom the process of making it grip the spool when winding on. It's not unusual for this last kink to lodge in the extruder or jam when being pushed back for unloading ...
The answer is to notice when the spool is nearng the end and cut off the kinked bit well before it vanishes inside the machine; then the replacement filament load will go cleanly.
Cheerio,
RE: End of filament handling
Very often the bitter end of the filament has a distinct bend or kink fom the process of making it grip the spool when winding on. It's not unusual for this last kink to lodge in the extruder or jam when being pushed back for unloading ...
The answer is to notice when the spool is nearng the end and cut off the kinked bit well before it vanishes inside the machine; then the replacement filament load will go cleanly.
Cheerio,
Thanks Diem - I'll try and keep an eye on it in the future, but thats not always possible. If there was a way for it to notice the X move I caused and re-home, that would be ideal. If not, having a menu option there to force it, or just have the printer automatically re-home in that direction when recovering from out-of-filament cases would be great too, if this is such a common occurance.
...and the other case where the bend is so strong that it prevents the end entering the extruder and so the sensor is not triggered and printing nothing in mid air ensues.
It's common to have a good idea when this might occur and even if there are a couple of dozen turns on the spool it does no harm to trim off the end so the filament slips off cleanly at run-out.
Cheerio,
RE: End of filament handling
Good tips - thanks! In this case it went through the hole in the top, don't know if it was able to make the turn around the gear or not, it went far enough to trip the sensor so it knew it was out. The handling from there could use some adjustments in the firmware like I described in the previous posts to recover better.
...and the other case where the bend is so strong that it prevents the end entering the extruder and so the sensor is not triggered and printing nothing in mid air ensues.
It's common to have a good idea when this might occur and even if there are a couple of dozen turns on the spool it does no harm to trim off the end so the filament slips off cleanly at run-out.
Cheerio,