New filament "not moving as expected"  

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Ian Bebbington
(@ibebbs)
New Member

Hi,

I recently purchased some "PETG HDGlass Transparent Green" filament (from Devil Printers but which was shipped directly from CEL - I won't be using Devil Printers again!). Unfortunately I've yet to have a successful print with this filament. Every time I try to use it I get the dreaded "filament not moving as expected" error. I've done the usual cutting back the filament to non-marked material and squaring it off to no avail.

Once purged, I can print successfully with my other filaments so think this filament must be faulty. Is this likely to be the case or might there be an issue with my Robox?

Thanks,

  Ian

Quote
Posted : 31/05/2019 9:49 am
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Pete
 Pete
(@pete)
I am Pete Admin

@ibebbs if you have some calipers (even cheap ones are really handy) please try measuring the diameter of the filament, check it several times along a few meters. Also check it is round by measuring twice in the same place but rotating the filament 90°.

It would also be good to test if the material is passing through the tubes and other parts easily without the head attached.

  1. Eject all filament.
  2. Power off <always do this when you fit or remove the head>.
  3. Remove the head.
  4. Power on.
  5. Feed the problem filament in.
  6. Use the controls to feed it so it passes all the way out past where the head would be feed it backwards and forwards a bit and see if there is any sign of extruder skipping. A chug chug chug sound.
  7. Eject again then power off before fitting the head.

Report to the service portal if it doen't improve.

For official support please create a support ticket using this link www.cel-robox.com/support/

ReplyQuote
Posted : 31/05/2019 2:36 pm
Ian Bebbington
(@ibebbs)
New Member

Hi Pete,

 

Thanks for the reply. I finally got a chance to do some measurements and can confirm that, over the first three metres, the diameter of the filament remains fairly consistent (and round) at about 1.75mm +/- 0.03mm. I trust this shouldn't be an issue for the Robox?

I don't believe - but am open to being wrong - that there's an issue with the Robox itself given I am able to print successfully with other filaments.

Please let me know if you think it's worth reporting to the service portal or whether I should be looking to return the filament as damaged.

Thanks, Ian

ReplyQuote
Posted : 07/06/2019 12:05 pm
Enginwiz
(@enginwiz)
Estimable Member

PETGs can saturate with humidity from the surrounding air if they are not stored in an airtight bag or container with silica gel. The humidity in the filament expands into steam at a volumetric rate of 1000 to 1 inside the extruder. This can give you all kinds of trouble from clogging feed pipes, excessive oozing, inconsistent material flow rate to bad layer adhesion and ugly prints.

Dry out your PETG filament for two weeks in an airtight bag with a pound of fresh oven baked silica gel. It is best to keep the rolls of filament in an airtight bag or container during printing. PETGs need to be bone dry to print properly.

ReplyQuote
Posted : 10/06/2019 7:33 am
Pete
 Pete
(@pete)
I am Pete Admin

What are you other filaments?

PETG is a big harder than ABS and doesn't flow quite as easily.

The hardness will effect how it can be gripped by the extruder gears.

Does it skip during purging?

You could heat the nozzles, open the valve and feed the filament using the buttons, these buttons have speed controls and should not skip (g0 commands do not have speed controls so might show skipping anyway).

While it is feeding through the nozzles listen for little pops and look for evidence of bubbles in the extruded material. Take care of the hot nozzles!

Bubbles and popping sounds will indicate wet filament which is harder to extrude.

This post was modified 1 month ago by Pete

For official support please create a support ticket using this link www.cel-robox.com/support/

ReplyQuote
Posted : 10/06/2019 11:02 am
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