[Solved] Filament Sensor (IR) problem  

RE: Filament Sensor (IR) problem

@masterhead

Thanks for the reply! I was trying UNDER the sensor and that was NOT working.  I'll try the sides.  I appreciate the help.

RE: Filament Sensor (IR) problem

In this post it says that it may work just loosing the screw

https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/filament-sensor-always-active/

The spacer under the sensor seems to work also, you can get it here:

https://www.prusaprinters.org/prints/8624-mk3s-ir-sensor-spacer-05-mm/comments

RE: Filament Sensor (IR) problem

Ok, I think my issue is more to do with the smaller magnet that is inside the fs_lever.  The tolerances were too loose so no matter what I didn during reassembly the magnet would pop out!  I'm reprinting the lever and hoping to get a tighter fit and maybe apply a drop or 2 of CA glue to hold it in pace during assembly.

RE: Filament Sensor (IR) problem

Hi, I've the same problem. Filament loading to the nozzle stops approx. 5-10 mm too early. extruder gear can't reach filament.

I'll try you "shim" idea, but my sensor is realy tight mounted. no room for a shim, i think buts lets give it a try.

MK3S MMu2    manufactured Dec.2019.

RE: Filament Sensor (IR) problem

Hi @all,

her is my fix. The sensor works fine unless i tighten the case. It take me some time to figure out, whathe the issues was.

If the Case is open, the Sensor works fine. After i close the case, the sensor doesnt work anymore. All things are moving but i got continourly a 1 from the senor. I take the Case apart again.... the Sensor is working like a charm..

My Solution: I gently scraped off a little bit of Platic and after i close the Case an tighten the screws it works....

I hope it helps someone with the same Issue....

Thx

Zh4ng

RE: Filament Sensor (IR) problem

@zh4ng-master-of-disaster

servus MoD, thanks. in the meantime a printed the workaround 
http://www.thingiverse.com/thing:3554066

I'll give it a try.

RE: Filament Sensor (IR) problem

@masterhead

Thanx - I had the same problem with a new printer (may 2020) - I just put an spacer of 0,8mm below the IR-sensor and now everythings works fine.

As using a spacer will cause trouble installing the cover again, i also made an new cover, you can find here for download:

https://www.thingiverse.com/thing:4459873

RE: Filament Sensor (IR) problem

Same here: thank you for posting. your analysis helped me solve the issue quickly and easily.

I've made a thin cardboard 'ring' (<1mm thick) around the small screw to sit between the PCB with the filament sensor's housing to increase the distance.

I agree that Prusa could improve the robustness here by checking the design tolerances. 

Moreover this may be included in the setup checks/calibration to manually check the filament sensor functionality before using the  printer. would have saved me a long print and some other issues, because i think it hasn't been working since the get go a few weeks ago.

so thanks again!
Jelte

RE: Filament Sensor (IR) problem

Just found this thread as I had the same problem on my MK3S+. Thanks for posting! I had printed the lever arm and filament guide piece out of ABS 6-8 months ago, but just the other day the printer kept thinking it was out of filament mid print. On examination of the two parts I couldn't actually see any wear on them visually, and when doing the sensor test I was seeing a solid 1 with filament inserted. I went ahead and reprinted them out of PETG anyways, and that solved the problem! The tolerances must need to be pretty tight as I honestly did not see any issue with my old pieces, but apparently there was one.