[Solved] Issue loading (Fibrelogy) BVOH filament  

RE: Issue loading (Fibrelogy) BVOH filament

I've followed the procedure (compressed air) outlined here: https://help.prusa3d.com/article/filament-sensor-mk4-mk3-9-xl_465702

 

Note that the hole in every of my extruders is too small (and more half-moon shaped, than circular) for the (vanilla) compressed air can I have

Two things to check:

Measure the diameter of the filament - is it within spec?  If too thin it won't trigger the default sensors.

Does the filament load OK to a different nextruder?

Er, actually three things; make sure the cable connectors for that toolhead are not loose (both ends).

Cheerio,

RE: Issue loading (Fibrelogy) BVOH filament

Posted by: @diem

Two things to check:

Measure the diameter of the filament - is it within spec?  If too thin it won't trigger the default sensors.

Does the filament load OK to a different nextruder?

Er, actually three things; make sure the cable connectors for that toolhead are not loose (both ends).

Cheerio,

 

Thanks for the suggestions:

Filament measures 1.72mm on a digital vernier caliper.

It did not load fine on another extruder.

Other filaments seem to load fine, so I imagine it's not a cabling problem.

RE: Issue loading (Fibrelogy) BVOH filament

Calibration sensors of of 1 and 4 failed.

After a (painfully time consuming, due to having to recalibrate docks etc) hard reset, 4 is still failing.

So: BVOH loading fails on all the heads you've tried but other filaments are OK.

Two sensors are causing trouble with all filaments, one remains unuseable.

This suggests two issues.

Something is off with the BVOH, it is a little undersized but not enough to explain the problem.  Examine it carefully, is the cross section flattened or uneven?

Two sensors are not registering as they should, one at least seems to have an intermittent fault.  I would always suspect a faulty connection or damaged wire first.  Pull and reseat all electrical/electronic connections and try again.

Cheerio,

RE: Issue loading (Fibrelogy) BVOH filament

Thank you.

The BVOH section seems fine, and extruded on extruder 2. For what it's worth, the prusament PETG (orange) that came with the printer, as well as the other filaments I've tested, test around 1.70-1.72 on that caliper (which I zeroed closed). So maybe the caliper is slightly off, but there doesn't seem to be a problem with the BVOH itself.

I've unhooked and re-hooked both cables in place (note, I printed a few dozens of hours before - that extruder included), but still get the same error on calibration. The sensor seems to detect when the filament is all the way through (I get the "Continue" message,  which when clicked results in "test failed").

Reached out to Prusa, let's see what they come up with.

The compressed air cleaning procedure is a pain, as the hole on the extruder is too small for the hose on the compressed air cans I have from amazon. I'm going to try with a 3d printed "funnel" (single wall vase), but it seems there is some procedure prusa doesn't publish on their website (they request to be contacted).

too small for the hose on the compressed air cans

Hmmm... simple design project ...

To make certain which sensor is acting up:   Take a short length of scrap filament and push it into the side sensor to trigger it and keep it triggered.  Undo he PTFE tube to the toolhead and push the working filament directly through the toolhead filament sensor; you will need to keep the filament above the printer somehow - and try again.

Cheerio,

RE: Issue loading (Fibrelogy) BVOH filament

I’ve been doing pretty much that: using a bit of (nicely cut / not stringy). filament (just a bit longer than the PFTE tube, so triggering the side sensor, while leaving enough for me to to manually insert / remove from the tool head), disconnecting the tool of the PFTE tube and inserting the filament (I also tried with it connected, not that it should matter). I can clearly feel the sensor being triggered. That said, now that you mention it’s possible that the issue is with the side sensor, but not sure how to test which one is faulty. 

Posted by: @diem

too small for the hose on the compressed air cans

Hmmm... simple design project ...

To make certain which sensor is acting up:   Take a short length of scrap filament and push it into the side sensor to trigger it and keep it triggered.  Undo he PTFE tube to the toolhead and push the working filament directly through the toolhead filament sensor; you will need to keep the filament above the printer somehow - and try again.

Cheerio,

 

The new firmware offers selective disabling - I haven't tried it yet.

Cheerio,

RE: Issue loading (Fibrelogy) BVOH filament

The problem has to do with the calibration process - I don't think sensors can even be enabled with the calibration not done (option appears greyed out).

The extruder sensor seems to sometimes read bad (OFF, when a filament is clearly in). 

I'm on 6.0.0 now (wow the printer is silent!)

Still no answer from prusa regarding the sensor cleaning procedure.

RE: Issue loading (Fibrelogy) BVOH filament

The issue seems resolved, by partially disassembling the extruder, removing the filament sensor, blowing air (I couldn't see any debris), and reassembling everything.

Calibration worked fine both on the prusament PETG and the Fibrelogy BVOH.