NinjaFlex vs. FilaFlex - Any opinions?

[3DPBuser]

Ninjaflex is a urethane based elastomer.

Would this make it inorganic, like silicone caulk?

[RobH2]

You can use this link to find the Data Sheet. It should answer your questions.

http://www.fennerdrives.com/25c4272a...e180419c/_/3d/

[3DPBuser]

Ah, looks like it probably has organic rubber:

will degrade and lose its elastic properties when submerged in water for extended periods of time.

[DonaldJ]

I've printed with 1.75 FilaFlex (from extrudables.com) with a modified extruder, and it prints nicely on a clean glass plate. Am still working with the settings, but so far I am very pleased.

From what I understand, it is acetone, solvent, and fuel resistant. I am not sure if other flexible filaments are the same.

[Gyrobot]

I am the UK beta tester for Filaflex, I also have NinjaFlex.

They are both Thermoplastic Polyurethanes (TPU).

The difference is the temperature they are extruded at during the manufacturing phase.

I can snap 1.75mm Ninjaflex by stretching it with my hands, Filaflex I can not.

Filaflex is more elastic.

Ninjaflex can be slightly easier to print due the surface roughness of the filament (due to extrusion temperature during manufacture)

Filaflex prints on cold glass.

Ninjaflex is recommended to be printed on a heated bed, although some users print on cold glass too.

Filaflex Safety Data Sheet : http://recreus.com/en/index.php?cont...d_attachment=8
Ninjaflex Safety Data Sheet : http://www.fennerdrives.com/FetchFil...a-e81b22ce9ad0

See my blog for more tips on flexible printing : http://www.gyrobot.co.uk/blog/how-to...ible-filaments
http://www.thingiverse.com/Gyrobot/designs

[curious aardvark]

Tried filaflex, ninjaflex and easyflex.
Except that easyflex is 3x cheaper :-)
Can't really choose between them.

But hands down my current favourite flexible filament is polymakr polyflex. Flexible pla. But prints just like good normal pla. Not as stretchy as the tpu/tpe filaments but just as flexible and just as strong - once printed.

[3DPBuser]

They are both Thermoplastic Polyurethanes (TPU)

Any idea then why they would degrade in water? I don't think PU does.

[curious aardvark]

oh yeah they all print on cold blue tape. I pretty much don't heat the build plate these days.

[Gyrobot]

Any idea then why they would degrade in water? I don't think PU does.

It could be the additives to make them print easier, that may have the problem, but to be honest, I don't know.

[pyrophreek]

In regards to why TPU is not recommended for long term immersion in water, a better understanding of the polymer chemistry is needed.

From Wikipedia:

The final resin consists of linear polymeric chains in block-structures. Such chains contain low polarity segments which are rather long (called soft segments), alternating with shorter, high polarity segments (called hard segments). Both types of segments are linked together by covalent links, so that they actually form block-copolymers.The polarity of the hard pieces creates a strong attraction between them, which causes a high degree of aggregation and order in this phase, forming crystalline or pseudo crystalline areas located in a soft and flexible matrix. This so-called phase separation between both blocks can be more or less important, depending on the polarity and the molecular weight of the flexible chain, the production conditions, etc. The crystalline or pseudo crystalline areas act as physical cross-links, which account for the high elasticity level of TPU, whereas the flexible chains will impart the elongation characteristics to the polymer.
These "pseudo crosslinks", however, disappear under the effect of heat, and thus the classical extrusion, injection moulding and calendering processing methods are applicable to these materials. Consequently, TPU scrap can be reprocessed.

What this means is that when you submerge the TPU in water, water molecules (which are polar) will slowly intercolate into the polar "crystals", and serve as lubricant between chains. This will cause the TPU to become swollen, and cause a loss of the elastic recovery response. How much of an effect this is depends on the exact chemistry of the specific TPU formulation, as they vary greatly.