Filament inclusions, how to prevent in the future?
 
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Bruce Labitt
(@bruce-labitt)
Estimable Member
Filament inclusions, how to prevent in the future?

I printed some black PETG.  Then I started using some green TPU.  I ran the purge a couple of times.  Every once in while, I get black PETG inclusions in my green print, even though I haven't used black PETG for many prints.  This last print, the black inclusion was in a bad place and was above the current Z position.  I measured it and it was 0.84mm above the current print position.  Of course, the print was knocked over.

How can the filament be truly purged?  Or do I need new nozzle assemblies for every filament?  (I hope not.)

The last time I attempted to post with a picture, I was blocked.  If I can create the post, I will attach a picture.

Posted : 16/01/2024 1:53 am
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Filament inclusions, how to prevent in the future?

It appears I am being blocked when I attempt to attach a picture.  It is just a jpg file.  3.2MB. 

Posted : 16/01/2024 1:57 am
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Filament inclusions, how to prevent in the future?

Left to right.  First print on left with large black inclusion.  Second print in middle with small black piece.  Third print with black piece at top of print.  This piece is 0.84mm above the flat top.

The big fat stripe down the side is not attractive at all and will have to be fixed.  But that is for a later time.  I need to be able to get successful prints with no PETG inclusions.

Posted : 16/01/2024 2:09 am
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Filament inclusions, how to prevent in the future?

My first attempts at including photos were all wrong.  Apparently adding photos via attach file aren't allowed!  Sorry about that.  Also learned that I had to reduce the size of my photo.

Posted : 16/01/2024 2:14 am
FoxRun3D
(@foxrun3d)
Famed Member
RE: Filament inclusions, how to prevent in the future?

Doesn't look like a purge problem to me, more likely PETG sticking to the side of the nozzle/heater block and at one point dripping on the print.

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Posted : 16/01/2024 7:15 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Filament inclusions, how to prevent in the future?
Posted by: @fuchsr

Doesn't look like a purge problem to me, more likely PETG sticking to the side of the nozzle/heater block and at one point dripping on the print.

Considering that a purge only pumps out 10mm of filament (or something like that) and a print consumes 30m or more, I would agree with you.  This is a new nozzle assembly.  I just did the upgrade a week ago.  So it is relatively clean on the exterior. 

Nonetheless there is some stuff on the exterior.  What is the best way to remove the external material?  Obviously need to heat everything, but what is recommended to "wipe" off the filament?  I don't want to use my fingers and a rag, that is a little risky.  Can one use some sort of wire brush?  Or something else?  Any recommendations?

Thanks.

Posted : 16/01/2024 7:26 pm
FoxRun3D
(@foxrun3d)
Famed Member
RE: Filament inclusions, how to prevent in the future?

For day to day cleaning of the nozzle I use a felt-type nozzle brush like this https://www.printables.com/model/69467

For more serious cleaning I use a run-of-the mill soft wire brush, e.g., https://www.amazon.com/gp/product/B0829ZTN57/

 

 

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Posted : 16/01/2024 7:35 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Filament inclusions, how to prevent in the future?
Posted by: @fuchsr

For day to day cleaning of the nozzle I use a felt-type nozzle brush like this https://www.printables.com/model/69467

For more serious cleaning I use a run-of-the mill soft wire brush, e.g., https://www.amazon.com/gp/product/B0829ZTN57/

 

 

Thank you!  That is very helpful.  Gives me some ideas what to do.  I have some wool furniture pads in the house, so I can try some.  I will look in my shop to see if I have some brass wire brushes.  If not, I will order them.  I do have a few small stainless wire brushes, but they would be too harsh on the hot end and nozzle.

Posted : 16/01/2024 7:49 pm
Bruce Labitt
(@bruce-labitt)
Estimable Member
Topic starter answered:
RE: Filament inclusions, how to prevent in the future?

@fuchsr  How thick are the felt pads for your felt nozzle brush cleaner?  Some of the Amazon reviewers for felt pads can't seem to agree on a measurement.  About how thick is needed?  Between 3-4mm?  The pocket seems to be about 18mm wide?

Posted : 16/01/2024 11:09 pm
FoxRun3D
(@foxrun3d)
Famed Member
RE: Filament inclusions, how to prevent in the future?

These are the ones I'm using: https://a.co/d/fXwXsxH

Formerly known on this forum as @fuchsr -- until all hell broke loose with the forum software...

Posted : 16/01/2024 11:15 pm
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