Experience with combined supports (PLA/PVA) with UM3?

[bjorn 9]

Hi,

I recently bought a UM3 as successor for my UM2+. Wow! Using PVA for supports, the results are amazing!

PVA is pretty expensive though, and I found the settings to use a different extruder for the support infill. I figured I best change the settings of the PLA to the settings when using full PVA supports (triangle pattern with 30% infill and z distance 0.

In theory, in this case only where the supports touch the model, a roof of PVA will be built upon the PLA base structure of the supports. This would save an amazing amount of PVA.

Does anyone have experience with this combined supports? Tips or tricks?

[bjorn 9]

Well since nobody seems to have experience with this, I'll share my own

The PVA supports stick very poorly to the PLA 'base' of the supports. In my case this resulted in loose PVA material contaminating the print. I stopped the print at that point, but I doubt if the supports would have worked at all. I forgot to take a picture, but thus far this seems not successful.

[SandervG 1,521]

Hi @Bjorn, thank you for sharing your methods. Am I right in understanding that the biggest part of your supports (everything except for the roof), is print with your build material, and only the roof with PVA?

That is a great way to save materials, and time since you don't have to switch heads that often. But it only works with supports on the outside right?

If your support is inside your model and you can not access it with a pair of pliers you have made a high quality maraca

[ultiarjan 1,223]

It's only great in theory.... he states it does not work.... and we already know pla/pva bonding is not the best, therefore the horizontal expansion is on by default in cura.

I wonder though if it might be a good idea to try on nylon/pva as the bonding is much better there.

[SandervG 1,521]

weird, I completely missed that. Curious to know if indeed Nylon would give better results..

[bjorn 9]

I just found this in the changes for Cura 2.4 Beta:

Improved PLA-PVA layer adhesion

The PVA jerk and acceleration have been optimized to improve the layer adhesion between PVA and PLA.

I might need to give it another try

[gr5 2,210]

ha. Don't bother. unless you use nylon.