1 Topic by Scum (edited by Scum 2018-03-23 19:12:26)

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Topic: Blending PVA and PLA

What do you guys think about blending PVA and PLA in a Filastruder? The two plastics have similar melting temperatures, so I wonder if a blended filament would be possible.

https://www.sciencedirect.com/science/a … 6196829132

The abstract of this paper seems to be promising. It says that PVA/PLA blends exhibit one glass transition temperature, meaning they're compatible. One caveat is that it seems they used a 95% PLA to 5% PVA mix, so I doubt that this combination would dissolve in water the same way pure PVA does. But perhaps a 50-50 mix would be possible and still dissolve in a short time span.

Thoughts? Anyone with a filastruder want to try it out? I found a relatively cheap mainland source (read: not 1000 tonne minimum order from Alibaba) for PVA here: https://www.soapgoods.com/polyvinyl-alcohol-p-713.html

2 Reply by carl_m1968

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Re: Blending PVA and PLA

The PLA will never dissolve unless you expose it to UV light and water for several years. Even if mixed with a chemical that does dissolve it would still be like mixing oil and water. You will still only have oil and water and the two will retain their individual qualities regardless of how will mixed they are. There are only a very few chemicals that will dissolve PLA near instantly like acetone does ABS. Those are chemicals you would not want to mess with to be honest. They are rather dangerous..

Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
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3 Reply by Scum

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Re: Blending PVA and PLA

Would the PLA even have to dissolve? In a mixture with a high enough concentration of PVA, wouldn't the PVA dissolve and the PLA just crumble away?

4 Reply by carl_m1968

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Re: Blending PVA and PLA

So how are you going to control where the PVA is in your print versus where the PLA  is when they are mixed? At the ratio described there will be very little PVA and you would most likely end up with PLA that has dissolvable voids.

Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.

5 Reply by IanJohnson

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Re: Blending PVA and PLA

PLA with dissolvable voids might be interesting.  Soaking in hot water might do nothing, make it matte, create a cool texture, or look terrible.

6 Reply by Scum

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Re: Blending PVA and PLA

carl_m1968 wrote:

So how are you going to control where the PVA is in your print versus where the PLA  is when they are mixed? At the ratio described there will be very little PVA and you would most likely end up with PLA that has dissolvable voids.

You wouldn't be able to control it any more than you can control how well your dye mixes with your raw plastic pellets when you extrude filament. And with a 50-50 ratio there would be plenty of PVA, possibly enough that the PVA would dissolve away and leave PLA without support that would just crumble away. The only thing I'm wondering is how the interface layers would work. I'm guessing the finish wouldn't be as nice as pure PVA, but if you had a triple extruder setup you could have pure PVA for the interface layers and a PVA-PLA blend for the rest of the supports.

7 Reply by IanJohnson

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Re: Blending PVA and PLA

I'm not sure if there is a slicer that does this, but the simplest thing would be to use regular PLA or whatever you are using in extruder 1 for the support, and then print solid interface layers in PVA from extruder 2.  No need to mix materials.

8 Reply by carl_m1968 (edited by carl_m1968 2018-03-29 15:47:54)

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Re: Blending PVA and PLA

Scum wrote:
carl_m1968 wrote:

So how are you going to control where the PVA is in your print versus where the PLA  is when they are mixed? At the ratio described there will be very little PVA and you would most likely end up with PLA that has dissolvable voids.

You wouldn't be able to control it any more than you can control how well your dye mixes with your raw plastic pellets when you extrude filament. And with a 50-50 ratio there would be plenty of PVA, possibly enough that the PVA would dissolve away and leave PLA without support that would just crumble away. The only thing I'm wondering is how the interface layers would work. I'm guessing the finish wouldn't be as nice as pure PVA, but if you had a triple extruder setup you could have pure PVA for the interface layers and a PVA-PLA blend for the rest of the supports.


Even if you mix 50/50 you would still have the PLA that will not dissolve and PVA that will. So you will either get patially dissolved layers and passes or you would go no dissolving. In either case this will not work in the way i think you want as the slicer and the printer has no way to control the PLA/PVA ratio in the layers.

As Ian suggested is to do it the way it was intended and that is to use one extruder for support material and one for the actual print.

What exactly are you hoping to get by mixing PVA and PLA?

Printing since 2009 and still love it!
Anycubic 4MAX best $225 ever invested.
Voxelabs Proxima SLA. 6 inch 2k Mono LCD.
Anycubic Predator, massive Delta machine. 450 x 370 print envelope.

9 Reply by dubbsd

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Re: Blending PVA and PLA

Hi Ian
I'm glad to see You are still on line
I  read Soliforum almost every day and havn't seen you online in a while.

Dale

Ultimaker S3.

10 Reply by Scum

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Re: Blending PVA and PLA

I'm well aware of the interface layer method. I'm not really looking to get anything out of this, it was just an idea that popped into my head. The interface layer method works perfectly unless you have internal or hard to get at supports, like with the gyro sphere that ultimaker used to show off their system. If such a thing would work, a blend of PLA and PVA would lessen the cost for total soluble supports.

11 Reply by genesat1 (edited by genesat1 2018-04-13 17:20:31)

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Re: Blending PVA and PLA

The first hurdle I believe would be getting that PVA from soapgoods to extrude.  If you succeeded at that (please do a writeup on it - I don't think anybody has done PVA filament) - then you could think of trying to mix it.  Sounds like you're wanting to make something like this right? https://shop.3dfilaprint.com/porolay-la … -858-p.asp / demonstration of printed object https://www.youtube.com/watch?v=2w-9KvBHago .