Nozzle repeatedly clogging while printing Ninjaflex TPU

[Jdo300 0]

Hello,

 

I'm having a problem printing white NinjaFlex TPU on an Airwolf3D AXIOM Dual Direct Drive printer. I am trying to run some test prints of a face mask ear strap but am having problems with the nozzle clogging shortly after the print starts (within the first 5 or so minutes). What happens is the print will start printing the first layer without a problem, but after printing the brim and the outline of the part, the nozzle starts clogging as it prints the infill for the first layer. I used the recommended profile settings on the NinjaTek product page as a guide for the settings and am using Apex (Airwolf3D’s rebranded version of Cura) for the slicer with the standard TPU profile modified with the NinjaTek settings for speeds.

 

So far, I have tried a deep clean of the nozzle (which was using ABS previously), and tightening the hobbled bolt in the direct drive hoping that would help. I also tried changing the Z offset from the table in case the nozzle was too close or far away from the bed. I have attached an image showing the part I tried to print, and a copy of the profile I used for the test print (you can still view the settings without having Apex). Can anyone give me some advice on what I can do to solve this issue?
 
Thank you!
Jason O

Apex TPU Profile.zip

[gr5 2,094]

The filament is probably not clogging but rather it goes all serpentine in the gap between the feeder and the hot end.

 

Just try printing slower.  Does this printer have a long bowden between the feeder and the nozzle?  If so add a drop of mineral oil every meter of filament printed.  It will not affect the print quality.  No one seems to ever believe me but it works well to reduce bowden friction.

 

So if you are getting 10% extrusion try printing at 1/10th speed.  At least go for half current speed.

 

Regarding pressure - you want low pressure.  Grip is not the issue.  "pushing a string" is the issue.  It's very hard to push a string - it just wants to curl up.  In fact I recommend the lowest possible feeder tension as if you squeeze the filament you will get a slower feed rate.  Not a disaster but it causes slight underextrusion.

[Jdo300 0]

@gr5, thank you for the great tips! I haven't had a chance to come back to this recently, but I plan to resume optimizing my profile soon. Hopefully I'll have some "Good" news for you once I try a few settings changes according to what you mentioned.

 

Thank you!

Jason O

Edited February 26, 2021 by Jdo300