Filament monitors setup problem

dc42

Now I am starting to undestand the calibration process. Sending M122 I always see no calibration data available unless I start a print with R-1, is it right?

With firmware 1.19, that's correct (or you could pause the print and then send M591 D0 R-1). In firmware 1.20 the data is accumulated even if you didn't use R-1.

claustro

Thank you
Still testing.
I have some false alarm from the sensor.

My intervention for now was to raise a little the print head form the bed but the problem remain.
How can I investigate and solve this problem?

Strangely the resume now work flawlessly , no more wrong extrusion on resume
Thank you
A.

dc42

You won't be able to use the sensor to monitor filament during a print nuti you have resolved the large tolerance that is reported in calibration mode. You are getting about +34% -146%. You should be getting results within about +20% -20%. Possible causes of the problem are:

1. Filament is not being forced back through the filament monitor during retractions, but instead it is buckling in the space between the filament monitor and the extruder instead.

2. Your extruder acceleration, maximum speed, or jerk is set too high, or your E motor current set too low, so that steps are being skipped (probably during retraction or un-retraction).

claustro

Ok at first glance none of this problems will suit to my situation . I'll test more and I 'll report.
thx

dc42

I suggest you try different sorts of movement, e.g. steady extrusion, and repeated extrusion and retraction, to see what type of movements are causing the problem.

claustro

Extruder 0 sensor: angle 238.4, ok, 24.27mm/rev, tolerance +12% -9%

this is what I obtained after an evening of tests.
At the end I completely reassembled the filaments and added a second ptfe tube.

It is quite difficult for me to understand how much hobbed gear and the front ball bearing should be tight .
The R variable in the config will be quite safe with 20 or will be better some more?

Thank you

dc42

That's a good result. Try R20.

claustro

I have inconsitent behavior from the sensor.
I start the print with 4% -4% and it goes smoothly , after a while I reprint the same things and the filament sensor give me false alarm and value og 20% -100%.

I am thinking about a problem with my spring loaded extruder

Also I have sudden stop of print without tehe usual popup telling me the filament is stopped .

01:52:18Printing paused
01:52:14Resume-after-power-fail state saved
01:51:51M24
Printing resumed

dc42

There is a known issue in the firmware, which is that you only get a popup message the first time. This is on my list to be fixed before the 1.20 release.

Your -100% suggests that the filament stopped moving due to a nozzle jam or an obstruction below the nozzle, or that the extruder drive has lost its grip on the filament.

claustro

Thank you for your explanation .
During on of my test the filament jammed at the nozzle but the filament monitor didn't stopped the print. It happened during a phase of the print with very small parts and lot of retractions, I could see the filament moving up and down through the filament monitor even if there wasn't extrusion, maybe this is was the cause of no alarm

If I understand correctly the positive or negative value of reported tolerance in M122 can give an hint of where is the jamming problem, can you explain me a little more?

dc42

The figure of exactly -100% as the lower end of the tolerance suggests that over one of the sample periods (which by default are every 3mm of movement), extrusion was commanded but no movement at all was observed by the filament monitor. I guess that an intermittent connection between the filament monitor and the Duet might have the same effect.

claustro

thank you for your clarifications, I made new connection of all sensor cable