I'm looking for tips on Spiralize with TPU

[TomB19 0]

I'm trying to print a small bellows.  OD is about 20mm.  It needs to allow articulation so I'm printing in TPU from a CURA slice with Spiralize.  The bellows part of it works terrific but I can't get the top of it to complete.  I have only tried without support, to this point.  I could print this in PLA and get 10 good parts out of 10.

 

It seems like this could be a case of a poor choice of gemetry.  I can modify the nozzle portion of this part but I thought I'd ask the group first.

 

I'm using an off-brand of filament (3d Sigma) that I have left over from another project but it's in a dry case and I don't suspect moisture problems.

 

Printer is a Creality CR-10S Pro.

 

Any TPU printing wisdom would be appreciated.

 

I've tried the following:

 

- Print speeds from 15 ~ 40 mm/s

- line thickness 0.4 to 0.7mm

- temps 215~225C

- I've made the nozzle angle as steep as 45 degrees (the pic shows a 40* version)

 

 

 

[TomB19 0]

Quick follow-up.

 

This bellows doesn't move very often so I am thinking of using PETG as a backup, at 0.08 or 0.12 layer height with spiralize.  I don't know how long it would last but it might be worth a shot.

[GregValiant 1,318]

You might try changing the line width also.  It's usually set to the nozzle diameter but can be different.  Try .6 line width and bump the flow rate % a bit.  If the top cone had steeper sides the individual lines might bond instead of falling into the center.