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Filament Sensor Bug on Mk3s?  

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Andrew Biss
(@andrew-biss)
Active Member
Filament Sensor Bug on Mk3s?

Hey all, very new user here. I set up my Mk3s in January and managed to print a Benchy without much issue. Now I’m trying to print my own designs and am running into a lot of issues. This particular one is minor but the easiest to explain.

I can’t get the AutoLoad Filament feature to work anymore. After selecting the correct filament and preheating, it says something like “click the button and insert the filament”. When I click the button, nothing happens, with or without the filament inserted into the extruder.

If I disable the 'Filament Sensor' in Settings, I am able to then select "Load Filament" and can then 'manually' load the filament.

Is this a bug? Hardware issue? Am I doing something wrong? I am pretty sure the feature worked when I first set the printer up and now it doesn’t. Thanks for the help.

Posted : 17/03/2020 2:56 am
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Filament Sensor Bug on Mk3s?

there is a small issue with the filament sensor and the FS Lever...   if the screw retaining the FSlever is too tight, then it restricts free movement of the lever, causing problems, and the positioning of the sensor board can change performance too, 
Some folk find that a thin spacer under the sensor, helps. 
https://www.thingiverse.com/thing:4006603

https://www.thingiverse.com/thing:4079248

regards joan

 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 17/03/2020 12:14 pm
mractor liked
0800peter
(@0800peter)
Active Member
RE: Filament Sensor Bug on Mk3s?

ISorry for german entry, but i am  running in reproduceable misbehave when changing material type in stopped print prior to start during heatup .

Ich habe einen Fehler in der Firmware.

taucht auf wenn Ausgangsbedingungen :

Drucker kalt pet-g geladen

Druck von SD gestartet mit PLA.

Druck während des Aufheizen gestoppt.

Filament entladen gewählt .
Filament Typ pet-g gewählt .

Drucker heizt normal auf PC Temperatur auf piept und fordert zum drücken des Knopfes auf .

Nach dem Drücken des Knopfes passiert nichts.

Irgendwann Nach dem Erreichen irgendeiner Temperatur entlädt das Filament spontan.

Wird der Druck dann fortgesetzt Beginn der Drucker nach einer Weile und fragt nach dem Entladen des filament des ob es entnommen werden konnte.

und schraubt auch mit dem Extruder das Filament raus obwohl gar keins drin ist.

Der Filamentsensor funktioniert definitiv.

 

autoladen filament ist eingeschaltet.

Drucker fordert dann nach Bestätigung dass das Filament entladen wurde, obwohl keins entladen wurde dazu auf neues filament zu laden was dann auch automatisch geschieht wenn man das PLA filament einlegt.

möglicherweise erkennt der Drucker das noch das pet-g filament geladen war und ich müsste den Druck gar nicht vorher anhalten um das Filament zu wechseln.

Das War mir aber noch nicht klar .
Und Ich weiß auch noch nicht ob es funktioniert.
Liebe Grüße Peter

 

 

Narren hasten, Kluge warten, Weise gehen in den Garten

Posted : 17/03/2020 1:07 pm
Mary Tillios
(@mary-tillios)
Eminent Member
RE: Filament Sensor Bug on Mk3s?

You read my mind. The same problem, but nothing helps me. Maybe I’m somehow inserting a thread ...

Posted : 17/03/2020 3:59 pm
Tom the Tomstar
(@tom-the-tomstar)
Honorable Member
RE: Filament Sensor Bug on Mk3s?

Are you shure your filamentsensor is really working all the time? Go to Sensor Information in the menu, take a short piece of filament and put it inside the extuder, just that much that you see the digit switching from 0 to 1. Do that rapidly.

With my printer I thought it works, but once in a time it just did not change back to 0 when I put out the filament. You can adjust the position of the sensor sidewards until everything reacts fast. Mine is very sensitiv now after moving it a bid sidewards. Also I put a little piece of 0.2mm 1st layer material beside to keep it in the one working position.

Posted : 17/03/2020 5:44 pm
Andrew Biss
(@andrew-biss)
Active Member
Topic starter answered:
RE: Filament Sensor Bug on Mk3s?

Thanks for the advice Joan. Would you happen to have any links to the forum posts that address this issue?

I had it working briefly. I went into Menu > Support > Sensor Info and saw that the IR Sensor was reading "0" with no filament inserted and would change to "1" after inserting a filament. 

However, this was short-lived. I'm trying to print with NinjaFlex and still figuring out how much tension is needed on the idler screw. Presumably I had it set too tight so the filament got tangled and wound up inside the bondtech gears. After getting the filament unwound, the sensor reports back "1" at all times. So I'm currently disassembling it to figure out what is going wrong. I'll report back with what I find. Hopefully this will help you Marry!

Posted : 17/03/2020 6:03 pm
Andrew Biss
(@andrew-biss)
Active Member
Topic starter answered:
RE: Filament Sensor Bug on Mk3s?

@tomstar

I saw your reply after posting my comment, that's what I'm currently working on figuring out! Thanks.

Posted : 17/03/2020 6:04 pm
nilok
(@nilok)
Estimable Member
RE: Filament Sensor Bug on Mk3s?

I ended up making a few different sized spacers to print in one go - and stacking them to see which combo gave me the best results using the sensor menu.  I had intended to print a final, single size......but after a month, I just kind of forgot about it.  I will see if I can find the file and upload them.

Is your printer grinding? Bearings squeaking? Motors smoking?
Step 1) Wash your Steel Sheet
Step 2) Return to Step 1

Posted : 17/03/2020 6:13 pm
Tom the Tomstar
(@tom-the-tomstar)
Honorable Member
RE: Filament Sensor Bug on Mk3s?

In my case I did not needed a spacer under the sensor, i just needet to move it a bid sidewards. Loosening the tiny screw a bit, moving the sensor around with one finger and triggering the switch with a piece of filament rapidly. I could see that in one corner the senser did not go back to ZERO when it should. This is how I found the sweet spot in the opposite corner. Pust some rests of 0.2 mm plastic beside that it can not move back to the bad spot. Just did it yesterday but I think its done fine now. I just check the sensor from time to time manualy.

Posted : 17/03/2020 6:18 pm
nilok
(@nilok)
Estimable Member
RE: Filament Sensor Bug on Mk3s?

Here is the link to my spacer set:

https://www.prusaprinters.org/prints/25728-prusa-mk3s-ir-spacer-set

Is your printer grinding? Bearings squeaking? Motors smoking?
Step 1) Wash your Steel Sheet
Step 2) Return to Step 1

Posted : 17/03/2020 6:49 pm
Andrew Biss
(@andrew-biss)
Active Member
Topic starter answered:
RE: Filament Sensor Bug on Mk3s?

I have it apart now and it appears to be working normally, which is frustrating because I know once I reassemble the problem is probably going to reappear. Not sure how to approach this issue.

Posted : 17/03/2020 7:24 pm
nilok
(@nilok)
Estimable Member
RE: Filament Sensor Bug on Mk3s?

Then it sounds like maybe the screw is tightening it down and out of place when assembled.  Try printing the spacer set and using the .5mm under the sensor. 

EDIT: just in case, PLA is OK to use for testing

This post was modified 4 years ago by nilok

Is your printer grinding? Bearings squeaking? Motors smoking?
Step 1) Wash your Steel Sheet
Step 2) Return to Step 1

Posted : 17/03/2020 7:27 pm
gmbarton
(@gmbarton)
Active Member
RE: Filament Sensor Bug on Mk3s?

I am having the same problem - unable to load filament.

 

How do you get to Sensor Information on the menu? If I go to Support, it lists website and other support options, but there is nothing about the sensor.

Posted : 19/03/2020 2:10 pm
Tom the Tomstar
(@tom-the-tomstar)
Honorable Member
RE: Filament Sensor Bug on Mk3s?

At the very bottom of the support menu. "Sensor status" or something like...

Posted : 19/03/2020 4:17 pm
gmbarton liked
gmbarton
(@gmbarton)
Active Member
RE: Filament Sensor Bug on Mk3s?

Thanks - I had not scrolled down far enough to the very last page of support to find the sensor info!

 

The filament sensor is stuck at 1 regardless if a filament is in place or not. I followed the instructions here https://help.prusa3d.com/en/article/mk3s-keeps-prompting-filament-change_2129

 

Once opened up, the sensor was working well - switches between 0 and 1 as the filament is inserted and removed. Then as I started to re-assemble, the sensor changes to 1 as I tighten one of the upper screws holding the extruder motor. How do I prevent this, so it works with the motor installed?

 

I already put a 0.5mm shim underneath the sensor, but doesn't seem to solve the problem.

Posted : 19/03/2020 9:35 pm
gmbarton
(@gmbarton)
Active Member
RE: Filament Sensor Bug on Mk3s?

I finally had success with nilok's spacer set. I was surprised how sensitive the mounting height can be.

The 0.5 plus 0.2mm nearly worked, but not reliably - still showing 1 sometimes when the filament was absent. The 1.0mm spacer was just a little too much and always showed 0 regardless if the filament was present or not. My solution was to round two of the lower edges (the shorter ones) and slightly sand the rougher printed side of the 1.0mm spacer with 600 grit sandpaper so it could fit a little easier. This gave reliable switching from 0 to 1 as the filament was inserted.

Posted : 21/03/2020 5:53 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Filament Sensor Bug on Mk3s?

Whenever you do a live z calibration using the Jeff's method you end up printing lots of 0.2mm single layers.  They also make great shims.  You can cut them up with scissors and punch holes in them easily.  Great for adjusting the height in 0.2mm increments.

Posted : 21/03/2020 9:46 pm
nilok
(@nilok)
Estimable Member
RE: Filament Sensor Bug on Mk3s?
Posted by: @gmbarton

I finally had success with nilok's spacer set. I was surprised how sensitive the mounting height can be.

The 0.5 plus 0.2mm nearly worked, but not reliably - still showing 1 sometimes when the filament was absent. The 1.0mm spacer was just a little too much and always showed 0 regardless if the filament was present or not. My solution was to round two of the lower edges (the shorter ones) and slightly sand the rougher printed side of the 1.0mm spacer with 600 grit sandpaper so it could fit a little easier. This gave reliable switching from 0 to 1 as the filament was inserted.

I included the f3d file in the set so people can make an exact-size spacer if needed - and slicing/printing at .1mm Layer Height should give a pretty accurate degree of control.

I have been hoping that people who print and use the set will post their result under the comments so I can start an average.

This post was modified 4 years ago 2 times by nilok

Is your printer grinding? Bearings squeaking? Motors smoking?
Step 1) Wash your Steel Sheet
Step 2) Return to Step 1

Posted : 21/03/2020 10:46 pm
nilok
(@nilok)
Estimable Member
RE: Filament Sensor Bug on Mk3s?
Posted by: @marry_till

You read my mind. The same problem, but nothing helps me. Maybe I’m somehow inserting a thread ...

Have you tried going up 1.2mm or 1.5mm with spacers?

Is your printer grinding? Bearings squeaking? Motors smoking?
Step 1) Wash your Steel Sheet
Step 2) Return to Step 1

Posted : 21/03/2020 10:50 pm
Bry
 Bry
(@bry)
New Member
RE: Filament Sensor Bug on Mk3s?

I have also had to adjust the height of the sensor but now the cover that goes over the sensor will have to be modified. The cutout in the cover C1 is not long enough to clear the sensor so when it is screwed in place it will push the sensor back down again and that will cause the sensor to give false readings again.

Posted : 22/10/2020 10:48 am
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