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reischlr
(@reischlr)
New Member
Purge PVA to support?

Dear Prusa-Community,

 

I just finished assembling the MMU2s and am very new to 3D Printing.

I am really interested into the PVA surface mode but as so often the material used for the wiping-tower is just as much as for the actual object. I was looking around for the idea I had about it but couldn't find anything.

 

Since I use PVA and PLA I can of course not use the purge to infill mode since then i would have soluble PVA inside my object right?  but what i would like to use as purge is the actual support-structure.
Is there a possibility to export the slices in a way that i have 3 separate objects? 

1. the actual model which i would print with PLA,

2. the surface touching the support which would be printed with PVA and

3. the support-structure which i would use as "purge to object" since i would not care about the purity of the support

Is there a way to achieve this and by that minimize the amount of material wasted in the purge-tower?

 

Just to elaborate my plan: here a cut through part of my object. You can see the object on top. The surface in green and the grid support material which i would like to use as purge.

Looking forward to your ideas,

Robert

Best Answer by Nikolai:

@reischlr

ok, got it. Based on my experience it's not practical. Support is pretty fragile and mixing it with a filament which is not very sticky, is not holding a support structure well. Beside of that there is usually not enough support to purge into it completely. The actual filament saving is not really significant and not worth the pain.

Posted : 19/10/2019 2:41 pm
Dave Avery
(@dave-avery)
Honorable Member
RE: Purge PVA to support?

PVA_test

here's a test 3mf that may work - i don't have any pva to test

Posted : 21/10/2019 6:10 pm
reischlr
(@reischlr)
New Member
Topic starter answered:
RE: Purge PVA to support?

Hi thanks for your answer but I am a bit lost what you want me to do with the file... it doesn't really solve the problem of making the purge go to the support material 😓 

Could you please elaborate how this file would help me? 🙂

 

Posted : 22/10/2019 7:04 am
Nikolai
(@nikolai)
Noble Member
RE: Purge PVA to support?

@reischlr

Your idea doesn't make sense to me. If you use PVA as support means you want to dissolve the support in water. But if you purge PLA into PVA support, it wouldn't be possible. That's why you usually want to have the opposite and keep this two materials as much separated as possible. 

In general you picked a pretty tough requirements as a start. I would recommend to print single material/color first (many different size and form objects) before you dive into advanced multi color/multi material printings. Getting your first layer issues, heat creeps, jams, cloggs, bad overhangs/bridges.... with a single color/material and simple object will help you to understand why you want PVA and when.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 22/10/2019 9:46 pm
reischlr
(@reischlr)
New Member
Topic starter answered:
RE: Purge PVA to support?

Well there is the option to safe PVA cost by just making the touching surface between support and object PVA so that the support would come off the object after dissolving the surface layer (as shown in the screenshot above). And I would like to use this function but let the rest of the support which would be clean PLA be the "waste tower" or at least as much as possible.
So i would get clean PLA in the object, clean PVA in the surface layer as usual and and make the support be a mix of both(=purge)

Posted : 23/10/2019 11:43 am
Nikolai
(@nikolai)
Noble Member
RE: Purge PVA to support?

@reischlr

ok, got it. Based on my experience it's not practical. Support is pretty fragile and mixing it with a filament which is not very sticky, is not holding a support structure well. Beside of that there is usually not enough support to purge into it completely. The actual filament saving is not really significant and not worth the pain.

Often linked posts:
Going small with MMU2
Real Multi Material
My prints on Instagram

Posted : 23/10/2019 5:45 pm
reischlr liked
reischlr
(@reischlr)
New Member
Topic starter answered:
RE: Purge PVA to support?

Hi Nikolai,

Ok Thanks! That seems reasonable.

🙂

Posted : 25/10/2019 6:41 am
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