Remove or prevent water in model

[KjetilSunde 0]

I'm printing with a water soluble support filament, and with low infill density. After placing the parts in water, to remove the support, the parts are filled with water.

I do not need a waterproof part, only a way to remove the water.

 

- Is there a infill pattern with open cells/open walls? (I can drill holes in some of the parts, but not all. And not always the top or bottom.)

- Is there a way to make the top or bottom less waterproff, so it will be self draining?

- Is there a way to make the part completly waterproof?

- Other sugestions?

 

Ultimaker PVA or equivalent.

[FRabe 5]

11 hours ago, KjetilSunde said:

Is there a infill pattern with open cells/open walls? (I can drill holes in some of the parts, but not all. And not always the top or bottom.)

The types of infill that are normally reserved for flexible filament might suit you best as far as not trapping water as much within the infill. Gyroid, and Cross 3D appear to have the least amount of pockets (when compared with triangles, cubic, or other traditional infills), but your shell is always going to print solid, or near solid.

 

What print material are you using? If you have good layer adhesion the parts should come out very near watertight as is. Adding additional wall lines can aid in this. 

 

I have only used PVA on one trial run, but had no noticeable issues with water getting trapped in the parts. These parts had 4 wall lines @0.35mm width and seemed to be completely watertight. Our issue came with how slow dissolving the PVA was. Perhaps because we didn't get water inside of our parts because we didn't soak, but instead ran the parts under warm water and scrubbed to remove the PVA.

 

The shape of the model will also play a part in how water tight the part is. Do you have pictures of the parts you produced, or an STL where I could play with settings?

[GregValiant 1,245]

Part of this is what you are using the infill for.  If it's for strength then "disconnecting" the interior structure will make the infill very weak.  If the infill is there just to hold up surfaces that are being printed above then there are a couple of things you could do.

Set the Infill Pattern to Lines, the Infill Layer Thickness to 2X layer height, and set the Infill Line Directions to [0,30,60].

That will give you a sparse (every other layer) infill and they will only line up every 7th layer.  That's enough gaps in the infill that water should migrate out your hole.  If you put holes in on opposite sides of the print you could add some pressure in one hole and blow the water out the other side.

[geert_2 557]

To make parts waterproof, I print them very slow, cool and in thin layers of 0.06mm. I made a filter for a vacuum pump this way, and tested it by putting water under pressure on it. No leaks. However, when printing in thicker layers of 0.3mm, the water jetted out through lots of tiny openings, where the nozzle had jumped to other layers.

 

When you print with water-soluble support, tiny strands of that support material might end up going through the walls of your model, which after dissolving could leave tiny gaps.

 

Chemically smoothing with dichloromethane should also close tiny gaps and make it waterproof. Or you could paint it. But chemically smoothing can cause cracks later on, because it weakens the chemical structure and might add additional stress.

 

I don't know about internal support structures, as I rarely use them. Another option could be to design custom supports in the model that suit your requirements (strength, removability, waterflow, whatever,...). For example you could design a custom tree-shape support with plenty of openings to wash away support, but still good strength. Probably I would go this route, if I had to design it.