[Closed] Flex-Filament question.  

Re: Flex-Filament question.

I've experimented a little with both.

TPU seems to have a lot more variety in terms of the colors and grades of available. One TPU I've been using is quite hard and prints almost as easily as PLA while still being flexible in thin layers. I've also experimented with a TPU that's almost as soft as a wet noodle and very challenging to print. TPU tends to have a slippery feel, and it's highly scuff-resistant. The TPU's I've encountered are flexible but not very stretchy.

There don't seem to be as many TPE varieties out there. The one I tried is more at the wet noodle end of the spectrum. It's also a lot more stretchy than TPU, and has more of a rubbery feel.

If you're looking for something to start out with I'd suggest a harder TPU. It will be easier to print and still give you a feel for the possibilities of printing in flex. This is the stuff I used that's almost as easy to print as PLA: https://www.amazon.com/PRILINE-TPU-1KG-Filament-Dimensional-Accuracy/dp/B074DSVJB3 . I've found that thin pieces (1mm or less) flex easily, while thicker bits are almost as rigid as PETG--which gives some interesting design possibilities for having flexible and rigid parts of the same model without multiple materials.

Re: Flex-Filament question.

As far as I know TPU and TPE are terms that is used interchangeably and refers to filaments with elastic properties. How soft the filament is, is determined by the hardness measurement: https://filaments.ca/blogs/3d-printing/15475957-shore-hardness-of-flexible-3d-printing-materials

The most flexible and softest material I have had success with is NinjaFlex with a Shore hardness of 85A.
More commonly is Fillaflex from fillamentum with a hardness of 98A. It can be used for phone covers and like, and has a PR Slic3r profile.

Re: Flex-Filament question.

As far as I know TPU and TPE are terms that is used interchangeably and refers to filaments with elastic properties.

Not quite. TPU flexes but does not stretch.

TPE will stretch quite a lot.

"Flex" could refer to either. I saw reel of filament at Microcenter yesterday that was just labeled "Flex" and I have no idea what's in the box.

Re: Flex-Filament question.

TPU - Thermoplastic polyurethane

TPE - Thermoplastic elastomer

TPU has issues with water/organic decay, and is much more oil/chemical resistant than TPE.
TPE - Is, basically Rubber in Plastic. It's not as strong, nor as elastic (as far as the specs sheet)

They are both Thermoplastics, and act rather similar, however, they are quite different in what they are and what they excel at.

What I really want is to print with this material.
https://www.ebay.com/i/121680883110?chn=ps

I have a few O-rings/Gaskets/Belts laying around, and I swear, it's one of the toughest, rubberyiest materials I know of, and it's supposed to fall into the TPU family of plastics.

It feels kinda slippery, but also non-slip at the same time.

As I said I am interested in it for 3 reasons.
1. Repeatablity of stretch/flex strength. (Hinge)
2. Use the material for feet... and pop-in plugs. (basicaly what you see most "soft" plastics used for, besides "grip".
3. If it feels like the Urethane belts I love so much... I just need it.

EDIT:
I'm thinking about getting some SAINSMART.

Not 100% sure if it's as soft / rubbery as I would like, but It's pretty, and flexy so a good starting point... lol.

Re: Flex-Filament question.

Hi there, I'm using this exact filament currently, might I ask what settings you're using to achieve good results? My first prints with this Priline TPU came out good, but I think a setting or two got changed while switching between profiles in Cura and now it's not printing as well.

I do keep the stuff sealed in ziplock bag with very little air and a bunch of dessicant WITHIN a drybox while I'm not using it, so I don't think it's moisture, but it seems like extrusion is becoming an issue and the last two prints the filament curled up above the extruder gear.

Any help would be appreciated!

If you're looking for something to start out with I'd suggest a harder TPU. It will be easier to print and still give you a feel for the possibilities of printing in flex. This is the stuff I used that's almost as easy to print as PLA: https://www.amazon.com/PRILINE-TPU-1KG-Filament-Dimensional-Accuracy/dp/B074DSVJB3 . I've found that thin pieces (1mm or less) flex easily, while thicker bits are almost as rigid as PETG--which gives some interesting design possibilities for having flexible and rigid parts of the same model without multiple materials.

Re: Flex-Filament question.

filament curled up above the extruder gear.

print slow at first. like very slow. see how fast it can go without curling at the extruder.

Re: Flex-Filament question.

filament curled up above the extruder gear.

print slow at first. like very slow. see how fast it can go without curling at the extruder.

These last few prints I've actually been printing slower than the first few that came out perfect, 20mm/s rather than 30, I just confirmed via gcode settings.

I came home today to a print which started off fine, for the first 10mm vertically or so then started underextruding, then eventually extruding nothing.

It printed another 30mm or so as thin air until I came home to stop the print.

It's seems like the tpu could be getting clogged?? It bunches up right UNDER the extruder gear, not above as I said previously, like the gear is trying to push it through the tube and nozzle but it's getting stuck. I drew out what's happening over this pic to help explain since it's hard to see.

This is the third time I've gone and swapped it back out with PLA, at which point once the PLA had flushed out the rest of the TPU it extruded perfectly normal, I would think a clog would affect the PLA too?

This is so much more annoying than dialing in a filament because it printed very well for three 12+ hour prints in the beginning 👿

Any ideas?

edit: I should add that this Priline TPU is a very rigid TPU, I think the shore rating is like 98 or so, it's supposed to be one of the easiest TPUs to print, as I first thought myself when those three big prints came out perfectly.

Update: Watched Maker's Muse video on printing TPU, my current print is coming out good so far, about 30mm vertically with no issue. The higher up it gets the rougher the walls look, but they're still even with no underextrusion.

What fixed it was (I think) a combination of printing slower at 15mm/s, a cold pull with PLA, adjusting Live Z down by 40um then compensating for lowered bed adheasion by changing first layer height from .15 to .25.

I'm pretty sure what was happening is the increased pressure within the nozzle caused by printing as I normally would with PLA (first layer squished real good to bed) was creating buildup in the nozzle, it would eventually cause the filament to kink right under the extruder gear because kinking got to be easier for the TPU that pushing through the nozzle against that pressure where PLA/ABS as rigid as they are wouldn't have a problem with this.

Very loose idler springs or almost as tight as PLA idler springs (14mm, not 13) changed nothing for me. Hot or cold bed changed nothing, 220c or 230c changed nothing. I'm pretty sure the speed, 15mm/s to 30/mms isn't the issue either as I'd been successful initially with the faster speed. I do know I had to run the Load Filament process 3 times with the PLA with which I was planning to cold pull before that white PLA was truly only white PLA with no black TPU mixed in, but the cold pull came out clean, so that may not have even helped. I have to guess that the initial printing done with this spool about 3 weeks I must have had the bed a bit lower like I do now, though I could have sworn I set it to print a first layer like I would PLA when I put the blue tape down so who the hell knows 😡

If this can help anyone out there with a similar situation I'm happy, there are surprisingly few threads that even mention back pressure from Live Z height and TPU clogs/kinks, the one post I found linked to the Maker's Muse video that you can find here