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Underextrusion...some of the time  

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Ghost Raptor
(@ghost-raptor)
Active Member
Underextrusion...some of the time

 

All,

Trying to troubleshoot why I have been getting under-extrusion. Testing setup below is 4 half spheres. The sphere in the upper right is not extruding enough PLA. The nozzle gcode instructions move from upper left object to upper right object, starting at the 9 o clock position of the sphere, going counterclockwise. It seems the nozzle will travel to the 3 o clock position before extruding the proper amount of PLA. 3 perimeters, 10% IF.

What I have tried:

-Re-seating PTFE tube in heatbreak (multiple times)

-Bottom where PTFE tube sits seemed clean, but I cold pulled anyway.

-New nozzle

-Raised heatbreak up

-Reduced tension on idler.

I'm confused why this is happening to only the one sphere. I'm assuming this happens due to the retraction, then pressure is lost, and takes a small amount of time to build up again. But why isn't this happening to all the spheres? If I print 1 object with continuous layers, I don't see an issue.

Any help would be great!

Posted : 12/06/2021 7:02 pm
cwbullet
(@cwbullet)
RE: Underextrusion...some of the time

Retraction is certainly a possibility but I cannot figure why it would only be in the back corner.  Retraction can cause under extrusion when the filament cools and causes a partial jam or when it reduced grip on the filament (chews).  Neither could happen in a single location on the bed.  They would tend to happen whenever there is retraction.  I would reduce retraction and see what happens.  

--------------------
Chuck H
3D Printer Review Blog

Posted : 13/06/2021 11:31 am
Ghost Raptor
(@ghost-raptor)
Active Member
Topic starter answered:
RE: Underextrusion...some of the time

Something I have been pondering, but is there anything that would affect the printing when changing layers?

Posted : 13/06/2021 8:51 pm
Dr. Kropp
(@dr-kropp)
New Member
RE: Underextrusion...some of the time

Could something about that position be causing the filament to drag as it comes off the spool or the spool not to roll as easily? I know when I print flex I used to see underextrusion at the extremes of the bed and I fixed it by adding PTFE tubing through the lid of my Lack enclosure.

Posted : 25/06/2021 9:13 pm
Ghost Raptor
(@ghost-raptor)
Active Member
Topic starter answered:
PTFE

I changed out the main PTFE tubing, and removed the PTFE tubing going into the filament sensor. This seems to have fixed the issue. Also, while changing the bowden tube out, I realized the compression fittings could have been too tight.

Posted : 18/07/2021 4:40 am
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