What is known about the air-tightness of 3D printed objects?

[AHG 0]

Are layer-by-layer 3D printed objects air-tight? I remember seeing some discussion on 3D printing facemasks during the beginning of the pandemic, some of the concern was that the masks would not be airtight. I don't remember seeing a definite conclusion.

 

Is anyone aware of tests or research on 3D printed layer porosity/permeability?

 

 

[SandervG 1,521]

Hi, not by default but it is possible to achieve. Some materials are easier to get air-tight then others. Post processing can help, or using the correct settings. For example, TPU is a good material to get air-tight. Printing slower usually contributes to getting a model air tight. 

[AHG 0]

Thanks for the response,

 

Do you know any articles or further reading on this topic? I am considering this as a research topic.

 

[Smithy 1,146]

I recently found to materials from Formfutura, they say that it is watertight, so it should be air tight too.

 

Formfutura Python Flex

Formfutura Centaur PP

 

But I think it is not a special formula of the Formfutura material. So as Sander already said, UM TPU could work for that as well because I guess the Python Flex is also TPU.

[geert_2 558]

I already said it in another post, but I don't remember which one, so I can't immediately find it...

 

Some time ago I printed a filter for use in a vacuum pump, to prevent ingestion of pieces. I tested watertightness by putting tap water under pressure (8-9 bar) on it.

 

If I remember well, it had a single outer shell, thus one pass of the nozzle. Printed at 0.3mm layer height it was not watertight: lots of small jets squirted out. But at 0.06 mm, printed slow and cool, it was absolutely watertight.

 

If required, chemical smoothing such as acetone smoothing on ABS will also greatly reduce layer-defects and improve watertightness.

 

The filter-effect was created by printing the bottom with 70% infill, or something like that (I don't remember the exact value, I tried a couple different ones), so it was a little bit porous. But the side-walls had to be watertight. After printing, both halves were glued together by adding glue around the mating edges.

 

 

[kmanstudios 1,120]

I have These three bottles that I made from UM PP and they have held colored water for a while without a single leak. I printed these just before the Christmas before my surgery, so...wow...3 years(!) They were printed using standard settings.

 

The blue one fell over and the coloured water leaked around the cap. This would require a soft (cork is the only material I can think of right now) gasket that would clamp down tightly when the cap is put on. They sell premade gaskets and would be easy to incorporate.

 

Red Bottle is logo'd "K-Bottle", The blue is "Tokah-Cola" done in the coke logo style and the green bottle is just plain. But, these liquids have sat in these containers since I made them.

[geert_2 558]

For sealing seams, maybe you could also make your own custom gaskets? Print a mould, and pour silicone in it, the kind of silicone that is used for, well, mould-making. Be sure to smooth the layer-lines of the mould, otherwise removal of the silicone will be difficult. Silicones come in various hardnesses, from flesh-like up to tire-like.

[kmanstudios 1,120]

20 minutes ago, geert_2 said:

For sealing seams, maybe you could also make your own custom gaskets? Print a mould, and pour silicone in it, the kind of silicone that is used for, well, mould-making. Be sure to smooth the layer-lines of the mould, otherwise removal of the silicone will be difficult. Silicones come in various hardnesses, from flesh-like up to tire-like.

That would be the 'have to do everything' approach 😂

 

I am not that good 😉