Filament Autoload not working  

RE: Filament Autoload not working

Same problem. Finished my build yesterday (01.12.2019), initial load worked but as soon as I wanted to change filament sensor kept reporting 1. Printed the spacer  by @armer_geddon ( https://www.prusaprinters.org/prints/8624-mk3s-ir-sensor-spacer-05-mm/files) now it worked. Will watch it and also report this issue to the support. Thanks @armer_geddon!

RE: Filament Autoload not working

I had the same problem, autoload flilament not working. Always a 1 on the ir display. I just cut a mm from the lever inside. Works like a charm.

RE: Filament Autoload funktioniert nicht

had today also the problem with the sensor was too tightly screwed now works autoload and recognizes now even if the filament goes to the bottom

RE: Filament Autoload not working

Posted by: @domlen

Same problem. Finished my build yesterday (01.12.2019), initial load worked but as soon as I wanted to change filament sensor kept reporting 1. Printed the spacer  by @armer_geddon ( https://www.prusaprinters.org/prints/8624-mk3s-ir-sensor-spacer-05-mm/files) now it worked. Will watch it and also report this issue to the support. Thanks @armer_geddon!

Exactly the same behavior / problem here. The spacer works at the moment fine. Thanks.

RE: Filament Autoload not working

@j_alison_w

Hmm. I had same. initial setup loads filament fine, then doesn't work after that

RE: Filament Autoload not working

To add another data point, I just built my MK3S last week and same problem. Initial setup sucked it right in and worked perfectly, but no dice after doing my first filament swap. Only worked with "manual load".  The rest of the build was *perfect* and I was meticulous and triple checked every step. Will try out the spacer tonight.

RE: Filament Autoload not working

I had the same problem on a newly assembled mk3s.

But all I had to do to fix it was slightly untightening  the screw holding down the sensor. 

RE: Filament Autoload not working

Posted by: @hstyborski

 I had the same problem after assembling my new mk3s, after some investigation I found that the extruder motor plate was interfering with the back of the fs lever.

I had to shave the back of the fs lever and the extruder motor plate at the interference and now everything works great.

I've been having a similar issue. The sensor and lever work perfectly with the extruder motor and plate removed, but when the motor is placed against the rest of the extruder, the sensor locks to 1. Something on the motor plate is interfering with the lever. I can see the lever shift slightly towards the sensor when the motor plate is installed, and it is this movement that makes the lever permanently trigger the sensor. So far I can not tell what on the motor plate is interfering.

RE: Filament Autoload not working

Same problem just occurred on my MK3s after (soon) 3 weeks light use, not more than 5 unload/load and only Prusa filament.
I could live with manual load, but not being without detection of filament running out.

Must say I am a bit disappointed about this "new and improved" filament sensor system. Will try adding the spacer tomorrow..

RE: Filament Autoload not working

@incendium87

It is the same for me. I tried shaving away a small portion of the edge which enables/ disables the IR Sensor as I suspected that it might just stick out a tiny bit too far because of the slight elephant foot. It did work well afterwards without the motor plate installed, but as soon as I put everything back together it showed the same behaviour as before, even after loosening all the screws attaching the motor and the plate. I suspect that the main problem is something interfering with the lever movement as stated before, but I was not able to pinpoint the culprit yet, so I just reinstalled the Spacer for now. I might try printing a new lever with printing quality turned all the way up and if that does not help either stay with the spacer or examine the motor plate more closely, if I find some spare time to do so...

RE: Filament Autoload not working

As far as I am concerned, my permanent solution is the spacer. No point trying to fix something that works.

I must not be an engineer anymore...

RE: Filament Autoload not working

@armer_geddon

So I found out what was interfering on mine. It was the bottom of the hole the steel ball rolls through. I just cut a corner into the bottom of the cylinder in the motor plate and it works well now. Adding the spacer may be an easier fix, but maybe one method works better than the other depending on what exactly isn't lining up right for any given printer?

Hopefully the pics bellow are of help to someone. When my printer is free, I'll try to get a picture of my modified motor plate.

RE: Filament Autoload not working

@robert-rmm200

Generally I would agree, that something that does work reliably does not need fixing. However my printer has developed loud rattling noises during fast extruder movements before. I imagine that the lever being stuck in a position that allows the steel ball to move freely and thus to rattle against the plastic is a possible source of this noise, as I have not been able to localize it until now. Too rule out this possible source of rattling, I am interested to get the filament lever to move as intended. Therefore I am grateful for the insight on how @incendium87 fixed the issue. I think I am getting a general idea of where the contact happened for you and will check it out soon 🙂.

RE: Filament Autoload not working

The pictures below show how I had to modify my motor plate to keep it from interfering with the FS Lever. In the second image, I've tried to highlight an approximation of the original shape and the material I removed. Of course, this interference is a result of the tolerances in the printed parts and  in my assembly. It is entirely possible that other printers interfere in a different location or have an entirely different problem that is keeping the lever from clearing the sensor path. Try to make sure you have a good idea of where your pieces are interfering before cutting into your parts. I found that having the FS Cover, the idler door, and the sensor itself removed while pressing the motor and motor plate against the rest of the assembly allowed me to better see what was interfering. If adding the spacer previously mentioned works for you, this may be a better solution.

RE: Filament Autoload not working

Tried shimming with no luck.

Completely removed the M3x8 screw - the FS cover seems to hold the IR sensor PCB in place firmly.

So far, no further 0, 1 false triggering issues.

Will report if that case changes. 

RE: Filament Autoload not working

Posted by: @armer_geddon

In case anybody else still has got this problem and wants a quick 3D-Printed solution, I have uploaded a 0.5 mm Version of the Spacer, which works fine for my printer, while 1 mm was to high. Of course I do not know if this will work with all Printers, but it's only 57 seconds to Print 😉 https://www.prusaprinters.org/prints/8624-mk3s-ir-sensor-spacer-05-mm

Thanks, worked for me!

RE: Filament Autoload not working

@incendium87

During the lockdown I finally got around to disassamble my Extruder and check, if the problem is similar to yours. Using your advice, I found out that my filament lever does not seem to catch on any part of the Extruder and moves freely. So it seems to be an issue with the filament lever dimensions, which could probably be solved by shaving away another portion of the upper edge or printing a new one with higher quality settings than the stock one. However since I now know that it moves as intended and hence should not be the cause of any additional rattling, I am fine with the spacer as a permanent solution for now 😉. This could also explain, why the spacer works for some printers while others would need higher ones, or the issue cannot be fixed by spacers at all, when the filament sensor catches at a high point.

RE: Filament Autoload not working

@armer_geddon

Perfect, thank you!

I had the same problem as everyone else and your spacer fixed it perfectly.

RE: Filament Autoload not working

Here is a full set and instructions for anyone who skips to the end of this thread: https://www.prusaprinters.org/prints/25728-prusa-mk3s-ir-sensor-spacer-set

RE: Filament Autoload not working

@kahl_l

This also worked for me thank you for your great work. oh and I love this Printer I have had it a week now and Wow is all  i can say. Thanks again for the quick and painless fix.