RE: Filament Sensor
Maybe a tip to also take a look at this forum thread:
Personally, I have a combination problem of the load cell sensor and the filament sensor, both of which do not work after turning on the printer. Leave your printer on for 20 minutes (10 minutes is sufficient for some other users) and then do a reset, then both sensors will initialize properly.
RE: Filament Sensor
this just happened to me too. not sure if anyone else figured this out... but i opened the idler door and placed filament in, closed the door. that managed to wake the sensor up. had to reopen, take it out and feed it as prompted.
RE: Filament Sensor
I’ve had the problem a few times. Once I had to hard reset. Other times opening and closing the filament door and blowing fixed it.
What I was wondering, is if this filament sensor is as persnickety as it is, what chance does an MMU have of working consistently?
I’ve been very happy with the Nextruders quality of printing and how easy it feeds. Not so much on its first layer ability with PETG on rough sheets, but overall an improvement over a MINI/MK3. But filament sensing seems to be a problem that Prusa has thrown about 3-4 different solutions at, and none seems that robust???
None of these Mk3.9/Mk4 kits or printers are ‘old’ by any means.
And so much for the display giving feedback to help diagnose and fix the problem. I also find that there seems to be less ways to manipulate the printer- like the ability to live Z for one. I know Prusa is proud of the new bed leveling, and it’s like ABS braking- for people that don’t know what they are doing it is a huge improvement. But if you know what you are doing, you can get a better first layer yourself- especially when it comes to adhesion.
RE: Filament Sensor
You can adjust live Z by pushing in and holding the dial while a print is in progress.
RE: Filament Sensor
@MileHigh
that’s the thing yeah? I mean the last time I had a problem with my MK3s+ I thought my bed level got off from being too rough on sheet removal and replacing but my poor .25 brass nozzle wash cooked. I get super clean first layers and better miniature prints from my 3.
4 is a good machine, on big prints some of the first layer imperfections don’t really matter, but on smaller more detailed stuff ehhh. I thought I saw a live Z the other day on accident somehow, who knows. I like the principal of the auto bed level but any oozing or a not very good nozzle cleaning and you get a comical result sometimes. I will say it’s gotten a lot better recently but still seem to get mostly slightly too low first layers.
In the first days of alpha input shaping I scraped an old purge Line off the bed during the leveling of a new print and it caused the nozzle to practically drill into the bed. during the print.
also got some etching when I got a clog on a first layer the first time trying PETG before I think they had a good pressure zone set up.
i don’t know. The 4 is supposed to be the updated 3S+ so there shouldn’t be any back stepping and it feels like there are a couple.
a live z lite might be nice. And fix on the filament sensor without purchasing a kit would also be nice. I think the problems on the FS could be both mechanical and firmware ended.
RE: Filament Sensor
My MK4 from kit works perfectly except that the filament sensor has never worked from new. I am technically competent and had no trouble with assembly. I have an MK3S+ also from kit , with thousands of hours of printing sucessfully, I have no problem maintaining these printers. I understand how the extruder and sensor work.
Symptoms:
1) Filament sensor changes between INS / NOTINS if you hold the filament 2cm above the extruder and move it side to side by hand.
2) Printer does not correctly recognise filament insertion
3) Printer does not recognise filament run-out, and continues printing without filament
Tests:
1)I have disassembled and cleaned out the filament sensor, it had some dirt in it but that did not fix it
2)The magnet spring and ball are all in place correctly
3) I can feel the ball moving when I insert filament - it is not stuck.
4) Hall effect sensor readings are approximately 600,000 without filament and 1,800,000 with filament inserted.
I'm now wondering if a longer or stronger spring would fix the issues: both of dirt, and of the ball-magnet combo perhaps not popping out far enough to let the sensor register as 'no filament'
RE:
My MK4 from kit works perfectly except that the filament sensor has never worked from new. I am technically competent and had no trouble with assembly. I have an MK3S+ also from kit , with thousands of hours of printing sucessfully, I have no problem maintaining these printers. I understand how the extruder and sensor work.
Symptoms:
1) Filament sensor changes between INS / NOTINS if you hold the filament 2cm above the extruder and move it side to side by hand.
2) Printer does not correctly recognise filament insertion
3) Printer does not recognise filament run-out, and continues printing without filamentTests:
1)I have disassembled and cleaned out the filament sensor, it had some dirt in it but that did not fix it
2)The magnet spring and ball are all in place correctly
3) I can feel the ball moving when I insert filament - it is not stuck.
4) Hall effect sensor readings are approximately 600,000 without filament and 1,800,000 with filament inserted.I'm now wondering if a longer or stronger spring would fix the issues: both of dirt, and of the ball-magnet combo perhaps not popping out far enough to let the sensor register as 'no filament'
My first run in with the filament sensor not triggering was about 3 months ago. When I disassembled to get to the ball clip, I had the impression that the insert for the ball was very slightly off to allow it to become a little more tipped in one direction if it's shaken just right. The second time, it ran out of filament and was still printing. FUN. I could salvage half of the print because several pieces completed, the larger ones not so much. Was happy to wake up to a beeping printer this morning when I checked on it and it had run out again.
The not so funny thing, the second time the magnet and air did not work. I was getting ready to take off the extruder cover and get to the ball insert but decided to just power -cycle and it started working again. That to me, besides really getting under my skin, says there should be some type of firmware issue. Anyway, Happy I didn't scrap 500g when it didn't trigger this time. I swear I would smash the thing.
RE: Filament Sensor
My ball holder (in mk3.9 upgrade kit) had extra flash around the ball end.
see my own question (answered by myself)
https://forum.prusa3d.com/forum/postid/678018/
RE: Filament Sensor
Suffering a filament sensor problem myself right now as well, if I pull the filament in the right direction (to the left apprently) it triggers but obviously that means that mid printing it decides there's no filament. Disabled sensor for now, will disassemble this weekend.
RE: Filament Sensor - fixed by recalibration
I cleaned out some crud from mine but that wasn't really the problem. I did 'recalibrate filament sensor' from the control menu and all works beautifully now. It seems that the initail calibration when first turned on did not work.
RE: Filament Sensor
I just encountered this. End of roll, filament unload, will not detect the new filament.
Reset and attempted calibration. The only way I can get it to detect new filament is if I put my finger on it and push it slightly left.
X marks the spot.
RE: Filament Sensor
My ball holder (in mk3.9 upgrade kit) had extra flash around the ball end.
see my own question (answered by myself)
https://forum.prusa3d.com/forum/postid/678018/
@osbock The ball being too tight? I want to make sure before I go shaving bits off. My mk4 is brand new.
X marks the spot.
RE: Filament Sensor
Yes, and it was pretty obvious by the rough plastic around the opening. If your's is smooth, I'd perhaps look elsewhere, but it seems like a fairly sensitive mechanism.
It's been working well for me since I did my little Shave and a Haircut..........
Two Bits!
RE: Filament Sensor
Slightly trimming the inside of the shaft where the ball sits worked well for me. There was a tiny catch happening, I assumed it was intentional to keep the ball inside, but with it trimmed and the recalibration, the filament sensor is working fine.
X marks the spot.
RE: Filament Sensor
Druck läuft weiter obwohl das Filament aufgebraucht ist. Was kann ich tun? Damit der Druck vernünftig mit Filamentwechsel fertiggestellt werden kann.
Just chiming in to say that my filament sensor on the MK4 seems to be on the fritz as well. When doing a filament change yesterday, halfway through the print it detected it had run out of filament. I removed the last remaining bit during the changeout. It never detected that it was removed and there was no way to manually tell it that the filament was gone. Locked on the "please remove the filament" screen. Had to reset the printer and lost my print.
Today, during a reprint, I ran out half way through and it never detected it was empty. Lost the print again. Went to try to recalibrate and got to the "insert the filament until the sensor detects it" but it never did.
I've been running the newest firmware a few days now. Reset it back to 4.6.4 and filament sensor still didn't work. Went to calibrate the sensor again and same problem. Decided to "unload" the filament that was not in it. It made some noise but nothing came out (because it was empty). However, when I went back to calibrate again, this time the sensor functioned properly.
Tried the magnet suggestion to no avail as well.
Not sure what's going on here but hopefully they address this issue quickly.
Mine was pre-assembled FYI.
RE: Filament Sensor
With the explanation as to why the MMU for the MK4 is not shipping yet, they have basically confirmed the problem though they have not addressed it here yet: It's those tiny strands of filament that get stuck when retracting. As soon as I read about them pushing it back for the first time I was pretty sure it was that reason and I was right. At least I get a $50 coupon out of it... -_-
RE: Filament Sensor
I've been basically resorting to trying to never run out of filament during a print... The air and magnet never worked. Twice now, I've removed the gear and filament sensor while the print waited. I never saw a piece of stringed filament, but both times, the sensor reset for me. I was then able to pop the gear back on and load the replacement filament without losing the print.
X marks the spot.
RE: Filament Sensor
With the explanation as to why the MMU for the MK4 is not shipping yet, they have basically confirmed the problem though they have not addressed it here yet: It's those tiny strands of filament that get stuck when retracting. As soon as I read about them pushing it back for the first time I was pretty sure it was that reason and I was right. At least I get a $50 coupon out of it... -_-
Where was the issue confirmed?
RE: Filament Sensor
In the blog post: https://blog.prusa3d.com/development-diary-update-on-mmu3-for-the-mk4_85043/
RE: Filament Sensor
Similar issues. Factory assembled. Printer fails to detect successful unload. Have tried trouble shooting with compressed air and cleaning filament path but to no avail. I am sometime able to trigger recognition of filament being removed by repeatedly inserting and removing filament. However, I have lost more than a few prints due to it freezing at the filament change screen and requiring a hard reset. I also had one fail when the filament run out sensor tripped despite there still being filament loaded.