Improve the ability to print in PVA only the interface support rather than the whole support

[Dadkitess 19]

Hey there,

 

We all know that PVA is a real mess and is hard to print for various reasons. It is also something that will reduce the overall quality of your print because of the PVA getting slightly stuck when dripping, because of pauses, flow being inconsistent, etc.

 

I've tried by the past to only print the 80% dense interface rather than the whole support, so that layer affected by the PVA are way less important, and it would avoid the famous BB Core jaming. But I quit, as it never really allow for good adhesion, leading to failures.

 

I tried once again yesterday, with the PolyDissolve S1 which is way better than the UM PVA, and... Well, I can't rely on it for small surface of interfaces. It won't stick enough on the PLA Tough to allow a confident use of it. It kinda work for 70% of the interfaces but it delaminates for the 30% other places. I'm not sure if a bigger surface would change something actually.

 

Do you guys have hints about it ? It really should be something possible and clearly interesting for many reasons ! Maybe a 3D interlocking ?

 

Also, one of the biggest issue with Soluble Support is the very short travel and retractation : CURA won't ever allow for large continuous optimized support path, unfortunately, even playing with the various parameters... I am sure that we don't care a 20% more support material being printed if it allows for successful path which are not jerky little points, dots and tiny segments that only want to delaminate and accumulate, even when it's PVA on PVA... There is a lot of way to reduce the whole Support Quantity, be it inverted conical shaped, tree, stages, etc, so it's not a big deal to increase the base support a little bit. And it would actually print faster, I always have a LOT of useless tiny sections and retractions all the time.

Edited February 13 by Dadkitess

[Slashee_the_Cow 274]

46 minutes ago, Dadkitess said:

There is a lot of way to reduce the whole Support Quantity, be it inverted conical shaped, tree, stages, etc, so it's not a big deal to increase the base support a little bit. And it would actually print faster, I always have a LOT of useless tiny sections and retractions all the time.

You want more support? You're a rare breed.

• You can use conical support with a negative angle to make the base of support bigger.
• If you use the Zig Zag support pattern it will do as much as possible in one continuous run, but it follows its pattern, so if there's something in the middle of a line, it'll do that as a separate segment..
• If you use the Cross support pattern and then turn on Connect Support Lines (which pops up when you select Cross) it will print the whole layer of support as a continuous line, until it gets small enough that parts start getting cut off (you can increase the density to make it take longer until that happens).
• Gyroid has the same properties as Cross, including the ability to connect lines so that it draws the whole thing as a single line, but because it doesn't run around the edge of the support, it's much less likely to get interrupted requiring a travel.
• For the interface pattern, Zig Zag will print an outline, then draw the whole pattern as a continuous line (again, where possible).
• Always remember that you can increase the support and support interface line widths.

[Dadkitess 19]

No... I don't want more support for the sake or more support, obviously, as stated in my message.

 

Thanks for the advices, i'll definitely try the Cross connected support lines. Gyroid has helped me a bit but did not do much for tiny patch of support (around 0.5 cm²).

 

Do you know if PVA and other brand alternative, are supposed to stick well onto the PLA Tough ? It actually does when the PLA surface is a big flat one, but I can't manage to get something reliable when it's a PVA interface onto a PLA Tough Support. It would need some kind of pre-interface in PLA Tough providing 2 whole full surface so that PVA can stick to it.

[Slashee_the_Cow 274]

4 minutes ago, Dadkitess said:

Do you know if PVA and other brand alternative, are supposed to stick well onto the PLA Tough ? It actually does when the PLA surface is a big flat one, but I can't manage to get something reliable when it's a PVA interface onto a PLA Tough Support. It would need some kind of pre-interface in PLA Tough providing 2 whole full surface so that PVA can stick to it.

I only have a lowly printer which only officially supports PLA, PETG and TPU, so I'm not a complete expert, but AFAIK none of the major types of filament adhere to each other that well (which is supposed to be the advantage of something like PVA), but I've printed PETG interface on top of PLA support without too many problems (the main annoyance being with a single extruder printer I have to swap between the two every layer there's interface) for a PLA model and it does significantly help (doesn't always work 100%, but quite ahead of getting PLA support off PLA model).

 

(I definitely wouldn't try using TPU. Too stringy and squishy for anything that requires stability, except other things made of TPU, but then getting support interface off is a massive pain because TPU is so soft a knife won't really cut bits off, I found some serrated blades for a utility knife and they're good at cutting bits off TPU... too good, unless you want to split your model apart.)