[FIX] Filament Autoload not working
Hi,
we run two i3MK3s; on the second printer I was unable to get the Filament Autoload function to properly work. I finally was able to fix it:
Long story short: The sensor was sitting too deep in the sensor recess in the extruder.
Long story: Tech support directed me first to check that both the IR sensor and the Autoload function wer switched to ON state in the main menu. Thereafter we checked the sensor status in the Support - Sensor Status menu; the IR sensor (shown as "IR") indicated "1", meaning the sensor was engaged all the time, thus wrongly indicating that filament was already loaded to the extruder.
I was directed next to check the magnetic switch in the extruder; possibilities were that I either had wrongly inserted the magnets (which I knew I had not) or that the little switch holding the small magnet was not moving correctly. To check this, I followed PRUSA´s instructions "How to replace PTFE tube". As soon as I had partially opened the extruder, the switch indicated a perfect "0" without filament; sticking a piece of filament inside resulted in a "1". Once I had reassembled the extruder, I was stuck again with "1".
Next I tightened a bit the screw inside the extruder which holds the switch, as the switch was actually on the loose side, tilting on the screw. It is impossible to turn the screw with an allen key (I even shortened an old allen key to the minimum length possible, to no avail). I ended up turning the screw with a pair of needle-nose pliers, gripping them tightly. Anyways, tightening the screw to a perfect setting did not help either.
Then I once again assembled everything and inserted the IR sensor again. Once I tightened the mini screw holding the IR sensor, the status indicator jumped to "1" again. Loosening the screw made it jump back to "0". Next I suspected that the screw was too long; I virtually shortened it by putting 2mm of tiny silicon hose under the head of the screw - nope, didn´t do the trick either.
Then I moved the piece of silicon hose underneath the sensor - pushing the screw through the sensor first, then pushing the hose on the screw - and then tightened the sensor.
Now I got to re-run the Z calibration; hopefully this helps someone to solve a similar mystery. Finally, I need to print a small sign to be mounted on the extruder, reminding me to watch out for the piece of tube and not to drop it into the extruder when disassembling again.
Cheers
Chris
I try to give answers to the best of my ability, but I am not a 3D printing pro by any means, and anything you do you do at your own risk. BTW: I have no food for…
RE: [FIX] Filament Autoload not working
Thank you! I had the exact problem.
RE: [FIX] Filament Autoload not working
Thanks, that was still valid for me! Whenever the sensor sits "perfect", it shows permanent "1". Putting something under the front part from about 1mm height (in my case some small piece of carton 😀 ) helped a lot. Not that highend of a fix, but it works perfectly and continously, so i call it a fix!
Cheers
Uwe
RE: [FIX] Filament Autoload not working
@kliem65
Good to know; happy that it works! In the meantime I ended up just leaving the screw a little bit on the loose side without anything put underneath, and it still works.
Regards
Chris
I try to give answers to the best of my ability, but I am not a 3D printing pro by any means, and anything you do you do at your own risk. BTW: I have no food for…
RE: [FIX] Filament Autoload not working
Thank you for this post!! It saved me from following the Prusa req of tearing the extruder down... Brand new build (from kit) and I was having the same issue. A little paper below the screw and now it's working perfect!! Given the date of this OP I can't believe Prusa has not addressed this already...
RE: [FIX] Filament Autoload not working
Chris, thanks for an excellent posting that put me on track to understand some background that led to discovery that my magnets were installed wrong.
For others working a similar problem, steps 5-7, 21-22 and 40-41 of this document might help.
https://help.prusa3d.com/en/guide/3-e-axis-assembly_48816
Pulling the top cover of the extruder exposes the IR sensor.
Removing the screw and lifting the sensor exposes the lever that is moved by the filament. Inserting a piece of filament should move the lever. On mine, it did not. If I pushed the lever gently to the right and released it, it moved back left indicating the magnets had been installed incorrectly. Fixing the problem by loosening a screw or changing a magnet requires partial disassembly of the extruder.
Quick Workaround: I did not want to take the extruder apart today so I deactivated the IR sensor with Settings/FilSensor. This also deactivates the AutoLoad feature and causes the load function to operate like the old Prusas: place filament in hole and select Load Filament.
RE: [FIX] Filament Autoload not working
Thanks Chris and All of you Guys, I'll check this.
For 2 days now (i'm a beginner, only 10 or 15 prints done so far) auto-fill is not working but even manual fill need to be answered "no" 3 or 4 times until the new color appears and once "Yes" pressed, the filament flows for 4 or 5 seconds!
The 2nd part is the weird thing... why filament flows after I selected "OK" but I know unexpected mechanical issue can lead to weird software things.
I'm printing an object with color change... unload/load worked properly !?!