nylon absorbes water? PVA?

[HPW 0]

Hello,

 

Ultimaker supports nylon in combination with PVA.

In this video the guy told around 1:50 that you should avoid using nylon with PVA.

He told that nylon would absorbe water. Who/what is right?

 

 

Regards

Hans-Peter

[Smithy 945]

Hmm, it is correct that the Nylon filament absorbs a lot of moisture from the air, more and quicker than PVA, so you have to keep both spools in a very dry place and depending on your air humidity also during printing.

 

But I think you mean if Nylon absorbs the water during the dissolving process of PVA. Good question, but I don't think that this is really a problem, but haven't tried it myself yet. And in case it absorbs a little bit, the model dry again when you have dissolved the PVA supports. If that were so sensitive, you wouldn't be able to expose nylon printed objects to higher humidity, but that's no problem.

[dxp 20]

Indeed it does absorb humidity after being printed. And it will become slightly larger. And the properties will change somehow. But you won't heat it up to 260°C, do you? So bubbles won't be a problem. Only if you are printing electrical isolating parts or something to work in a strong electrical field, it can be a problem. But otherwise - the properties will be better.

[BiMNrd 11]

Hi guys, trying to learn from others here a bit. So nylon will take in moinsture after being printed, but that will not impact its strength and mechanical properties?  

 

 

[Ishy 8]

Not sure if it's of any use but I currently have some ultimaker nylon parts in use in Arizona. They are being being subjected to water and the sun daily and not fairing well either structurally or dimensional y.

[DF-Werkzeugservice 9]

The water absorbtion of nylon is a kind of double-edged sword:

 

Before printing, you don't want the material to absorb moisture. Because of the heating in the printcore, the absorbed water will create bubbles and give a bad surface, little holes and in the wors case clog your nozzle. 

So it's important for the priniting process to keep the nylon filament dry.

 

After printing, the model will absorb moisture out of the air and of course when it's put into water. But this does not affect the properties of the material in a negative way. It will make your model slightly stiffer more impact resistant. 

[P3D 45]

1 hour ago, DF-Werkzeugservice said:

The water absorbtion of nylon is a kind of double-edged sword:

 

Before printing, you don't want the material to absorb moisture. Because of the heating in the printcore, the absorbed water will create bubbles and give a bad surface, little holes and in the wors case clog your nozzle. 

So it's important for the priniting process to keep the nylon filament dry.

 

After printing, the model will absorb moisture out of the air and of course when it's put into water. But this does not affect the properties of the material in a negative way. It will make your model slightly stiffer more impact resistant. 

 

Stiffer? That's not really my experience... in my experience, it becomes less stiff and more impact resistant after absorbing humidity.

 

On 10/13/2019 at 3:50 PM, Ishy said:

Not sure if it's of any use but I currently have some ultimaker nylon parts in use in Arizona. They are being being subjected to water and the sun daily and not fairing well either structurally or dimensional y.

 

I found some interesting Nylon degradation test results here: https://www.toray.jp/plastics/en/amilan/technical/tec_003.html 

I find this quite shocking, especially the extreme brittleness (total lack of impact resistance) the samples showed after only a year of exposure... 

[alexjx 8]

Actually, I think the video had made an incorrect claim against nylon. It will absorb water, but for a printed part, moisturization might be the wanted result.

 

Nylon demostrates different properties after absobe water, it will be more flexible and "tough". 

And actually, some nylon parts manufactures demands certain degree of moisture.

So I would put the printed parts into water to make it more "stronger".

 

 

[DF-Werkzeugservice 9]

12 minutes ago, P3D said:

 

Stiffer? That's not really my experience... in my experience, it becomes less stiff and more impact resistant after absorbing humidity.

 

 

I found some interesting Nylon degradation test results here: https://www.toray.jp/plastics/en/amilan/technical/tec_003.html 

I find this quite shocking, especially the extreme brittleness (total lack of impact resistance) the samples showed after only a year of exposure... 

 

Sorry, you are right... the word I was looking for was actually not "stif". What I wanted to say is that it would be stronger against breaking.

I'm not a native speaker, sorry 😉

[BiMNrd 11]

great info guys, thank you very much !!

So nylon will be somewhat flexible compared to ABS which will make it tougher?

[Oliveros 11]

I can tell you for sure the nylon i've used (Kodak 6) becomes extremely flexible once exposed to water.

 

I put it through a dishwasher and I could bend it easily any way I wanted and it would spring back in place. Once it got wet, It never went back to being as ridgid as it was once it left the printer.

 

Apparently, the more water it absorbs the more flexible it becomes until it's saturated. It didn't seem any less strong, just way more flexible.

[BiMNrd 11]

So I wonder what is the case use for such properties. Because if I want flexible, there is rubber or TPU.

[Oliveros 11]

The difference I would think is that nylon still maintains a certain amount of ridgidness, more than I can imagine rubber would.

 

I have no experience with TPU so I can't compare.

 

I like Nylon, it makes really nice prints with a very smooth texture, much better than ABS or PETG.

[BiMNrd 11]

Would you be willing me send me a sample part? DM me.