Soft TPU

[Pridanc 4]

Folks, 

I've been successfully printing 95a TPU but am in search of something softer so today I've tried printing with some 30D (about 80a).  The print starts out perfectly IMO but early on the TPU stops extruding. As usual, the print continues but of course nothing happens as there is no filament.. I've only tried this twice so far and the failure has happened at layers 8 to 11 respectively where all movements are similar.

 

This new avenue has me using a range of settings called for by the filament maker and have included the .3mf file as a just in case.  

 

I will take the time to watch the printer like a hawk on round 3 as something might jump out but my bride will tell me that since the obvious always escapes me, why bother?   However, if anyone out there has any thoughts of a direction I might go to solve this, feel free to speak up!

 

Dual gear DD extruder on an Ender 3 v2.   Not afraid to go to a better extruder either so I'm all ears as this geared extruder isn't the top of anyone's line.  It has served well to date however. My only regret is that I'm not sure what vs. CURA I sliced this in!  5.6 or 5.7.0  beta-1?  Sorry about that.

 

Thanks in advance for any thoughts,  PDC

TPU 30D CB Headlight bulb grommet .3mf

[Slashee_the_Cow 438]

Unfortunately while I seem to be the resident TPU weirdo I'm not sure I can offer too much advice since I've never tried anything other than 95A (not impossible to find softer, but not as easy as going to Amazon and ordering some 95A, plus shipping costs in Australia tend to be on the high end so I make plenty of use of my Prime membership).

 

I'd be very much looking at retraction first - specifically, avoiding it wherever possible (and maybe limiting it using Travel > Maximum Retraction Count and Minimum Extrusion Distance Window and/or increasing Travel > Retraction Minimum Travel). 95A is soft enough that it can get ground up if it goes back and forth through the gears too much (hence why I often opt for strings rather than a failed print) so I'm guessing softer is worse.

 

But just looking at layer 11:

 

That has 17 retraction moves (the ones in light blue) in not a huge amount of filament. A lot of them are very close together (in the support interface).

 

Layer 18:

15 retraction moves.

 

Or I could be completely wrong and it's something else entirely. Make sure you're printing at the right temp and slow enough (I usually set it to 20mm/s for everything).

[Pridanc 4]

Slash,

HUGE thanks and I will look into it. BTW, this is the headlight bulb "electric connections"  rubber-ish cover that is no longer made for the 1961 bike I'm restoring.  So far I feel this material is flexible enough to do the deed. Point being, and as you can probably see, it is rather small.  

 

I'd love to leave out the support but so far have been unable to with the thing collapsing on itself during print.  This thing does print perfectly in 95a.

 

And I might even try that filament that changes it's flexibility properties based on the temp you extrude it.  Fun and games are on the horizon to full steam ahead!

 

I will keep you informed for everyone's future knowledge but I will mark this as resolved.

Again, TYVM,   PDC

[NTwoO 8]

Is foaming ninjaflex an option?

[Pridanc 4]

NTwoO, 

Foaming filament is exactly my next try but: a)  not until I've actually completed a print with the 30d stuff I've go now and b) also not until I educate myself a bit on the current crop of foaming filaments. 

 

At this instant, I'm looking at ColorFabb Varioshore as I know some folks who've used it but I will also look into Foaming Filaflex as well as others I find.

 

All of the foaming tech is very intriguing, meanwhile, back to the farm...TYVM   PDC

[Jaaaacccck 0]

Years ago I set up a Cura profile and had squishy PETG prints for days until I figured out what it was.

 

So yesterday I was printing a TPU washer and it was way too firm and I tried this in Prusaslicer and it worked!

 

I simply told my slicer that my filament was 2.85 mm instead of 1.75 mm.  No other changes . .  

 

Background

I always print TPU with retraction turned off FWIW.

I tend to use run-of-the-mill Yoyi  TPU which is on the harder/less flexible side of the spectrum.

 

Let me know if you try 2.85 and get similar results.

[Slashee_the_Cow 438]

12 hours ago, Jaaaacccck said:

I simply told my slicer that my filament was 2.85 mm instead of 1.75 mm.  No other changes . .  

That's the equivalent of setting Material > Flow to about 38%. Either your print settings are set up to print harder than you'd like or you're massively overextruding (which is unlikely to be a hardware issue since TPU is a bit hard to feed in the first place, but could be the e-steps or something).