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whoneyc

Consistent Feeder Grinding Issues

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I am having a consistent issues with my feeder grinding filament rather than feeding.  What does this grinding/feeding issue look like? When the filament gets stuck at the extruder head or flattened by the feeder axis, the toothed wheel grinds a semi-circle into the filament.  See here.  This is occurring nigh-constantly on Feeder 1 of my machine.  It always occurs during the same point of the cycle: about two layers in, the surface of the print begins to look sputtered as it is failing.  Then nothing comes out.

 

The device in question is an Ultimaker 3 Extended with up-to-date firmware.  I am running PLA to an AA core.  The issues have occurred across multiple brands of filament.  I doubt there are any humidity issues; brand new filament has problems too.  To date I have attempted the following to fix the issue:

 

Hot/cold pull of AA print core (the core pulls cleanly, so I doubt it is clogged).

Feeder spring tension adjustment. Info at the bottom of this page. (When the gauge is at the top of the meter on the side of the feeder, it exhibits the issues described above at ~layer 2.  When it is below that point, it doesn't feed anything from the beginning.)

Use of compressed air duster to clean ground PLA material from feeder. Info at the middle of this page.

 

What's going on here?  Is there something I have not tried to remedy this? Does anyone have a tensiometer which can be used to check the force applied by the spring of a working feeder?  Should I contact the distributor at this point to request help?

 

Thanks for your assistance.  I'd be happy to provide additional info upon request.

 

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The feeder gauge should be in the middle or for very hard filament at 3/4 versus the bottom.

I recommend to set the feeder gauge to the minimum, then open the feeder case (if you don't set the feeder to the minimum then good luck looking for the spring and other parts ;-) ), take a brush and thoroughly clean the knurled bolt. Then close the feeder again and set it to 1/2.

You also may want to check if you can push PLA through the AA core in question easily. For that move the head into a corner at the front, then remove the bowden tube and gently push PLA directly into the printcore while heated to something like 210°C. You should not have to push hard.

The third thing you can check is if your Bowden tube is somehow damaged. Take a one meter long piece of filament which has not yet run through the feeder (aka without bitemarks) and run it through the detached Bowden tube from the back to the front. If you feel a sudden increase in resistance, then exchanging the Bowden tube might be a good idea.

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11 minutes ago, Dim3nsioneer said:

The feeder gauge should be in the middle or for very hard filament at 3/4 versus the bottom.

I recommend to set the feeder gauge to the minimum, then open the feeder case (if you don't set the feeder to the minimum then good luck looking for the spring and other parts ;-).

 

I have tried 1/4, 1/2, 3/4, and full settings for on the feeder gauge, all have had problems.

 

11 minutes ago, Dim3nsioneer said:

take a brush and thoroughly clean the knurled bolt.

 

As stated in my original post, I have cleaned the knurled bolt with canned air.  I'm not sure if "canned air" or "air duster" are terms used in your regional version of English, but the product I am referring to can be seen in this image.

 

11 minutes ago, Dim3nsioneer said:

You also may want to check if you can push PLA through the AA core in question easily.

 

The PLA was hand-pushed through the extruder core during execution of the hot pull cleaning method.

 

 

 

Edit:

I forgot to add that the Bowden tube appears undamaged.  There are no crimps in the PTFE tubing and filament has no problems getting to the print head during the initial filament loading.

 

 

Edited by whoneyc
Forgot to respond to last part of comment.

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@whoneyc - what are you printing?  If it has tons of retractions that could be the issue.  Look at the part in layer view and check the "blue" checkbox to see travel moves - the lighter blue lines (lilac?) are retraction moves.  If you have too many of those on the same spot of filament you will get the grinding you describe.

 

Or if you just print too fast and too cold you will get grinding.

 

If you have too many retractions on the same piece of filament you can grind it to dust.  10 is usually safe.  20 is in the danger zone.  50 should guarantee failure.  You can tell cura to limit retractions to 10 per a given spot of filament.  Do this by setting "maximum retration count" to 10 and "minimum extrusion distance" to your retraction distance (4.5mm for UM2 and 6.5 for UM3).

 

Maybe you should post how fast you are printing to see if you are going too fast (things speed up on the second layer).  Please post

layer height

print speed (all of them)

line width (all of them)

nozzle size (is it AA 0.4?)

nozzle temperature (all of them)

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@gr5

 

59 minutes ago, gr5 said:

Maybe you should post how fast you are printing to see if you are going too fast (things speed up on the second layer).

 

Sure thing.  This print is a combo of PLA in core 1 (AA 0.4mm) and Breakaway in core 2 (AA 0.4mm)

Layer Height: 0.2 mm

Print Speed: 70 mm/s

Travel Speed: 250 mm/s

Print Accel: 4000 mm/s^2

Travel Accel: 5000 mm/s^2

Print Jerk: 25 mm/s

Travel Jerk: 30 mm/s

Line Widths: 0.35 mm unless noted below

Inner Wall Line Width: 0.3 mm

Infill Line Width: 0.5 mm

Initial Layer Line Width: 100%

Printing Temperature: 205C/230C for each respective core.

 

1 hour ago, gr5 said:

If you have too many retractions on the same piece of filament you can grind it to dust. 

 

There are quite a few retractions.  I assume this is a necessity when swapping cores for the breakaway.  See attached image for retractions.  I can't post the gcode due to NDA issues, but this image alone shouldn't violate that. 

retraction_gcode.png

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Supporting images added. 

 

I decided to twiddle with the tensioner again and try to print.  I'm on a deadline for this project, so I have to keep trying.  Perhaps I will have done things the right way by adjusting the tension a bit or gave sacrifices to the correct unholy entity.

 

 IMG_20180415_190557.thumb.jpg.615f65a3e099556e5b576f68e750dc43.jpg

 

In this image there are snips of the failed filament. Clockwise from top left is: the ground down area that ended the run, a section from the middle of the remaining filament which appears to have had grinding issues, and the filament next to the final failure point which shows repeated grinding spots which support the sputtering look I observed.

 

IMG_20180415_185303.thumb.jpg.7ecde30d32a4c2500f0a158a6063990d.jpg

 

This image shows the state of the feeder when I removed the casing.  Note the tensioner is in the topmost position, as this run was an experiment to see if I could print in this position (I'm back to trying 3/4 at the moment).  The dust is from a single run, as it was cleaned prior to this attempt.  

IMG_20180415_190557.jpg

IMG_20180415_185303.jpg

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