TPU printed tube is air permeable while I need non-permeable
 
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TPU printed tube is air permeable while I need non-permeable  

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sebastiaan.v2
(@sebastiaan-v2)
Active Member
TPU printed tube is air permeable while I need non-permeable

For simplification (as the real shape is more complex) the following situation.

I print a hollow tube with Ninjaflex TPU in vertical position with a wall thickness of 2mm.

Print goes very well but when I close one side of the tube and blow on the other side, the air escapes.
For me this is kind of a surprise as wall thickness it 2mm (at smallest point) and also all looks very well molten together.

Layer thickness is 0.2mm, all speed at 15, temperature 230°C

Any suggestions or solutions?

Posted : 25/04/2017 6:23 pm
gz1
 gz1
(@gz1)
Estimable Member
Re: TPU printed tube is air permeable while I need non-permeable

Spray the part with soapy water and see precisely where the leaks are.

Posted : 25/04/2017 6:41 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
Re: TPU printed tube is air permeable while I need non-permeable

Hi Sebastiaan
is the tube made completely with perimeters? if not, the wall is only as thick as the sum of the perimeters...
can you try a slightly higher temperature for the filament to encourage better inter layer bonding?
regards Joan

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 25/04/2017 6:43 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Re: TPU printed tube is air permeable while I need non-permeable

What extrusion width are you using?

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 25/04/2017 6:57 pm
sebastiaan.v2
(@sebastiaan-v2)
Active Member
Topic starter answered:
Re: TPU printed tube is air permeable while I need non-permeable

Infill = 100%

- Layer height = 0.2mm
- First layer = 0.2mm

Vertical shells:
- Perimeters = 3

Extrusion width = 0.45mm

Overlap = 25%

Any suggestion based on this?

Btw - I did use the fan after first 3 layersas it is recommended by Ninjatek:

Extruder Temperature: 225°C – 235°C
Platform Temperature: Room temperature – 40°C
Top and bottom layers: 10-20 mm/ sec (600-1200 mm/ min)
Infill speeds: 15-35 mm/ sec (900-2100 mm/ min)
Layer 2+ use cooling fan if available.

Maybe that is not smart?

Posted : 25/04/2017 7:10 pm
sebastiaan.v2
(@sebastiaan-v2)
Active Member
Topic starter answered:
Re: TPU printed tube is air permeable while I need non-permeable

This is the printed part. The hollow part is 8mm all way from top to bottom. Walls are 2mm thick on the smallest part.

Posted : 25/04/2017 7:19 pm
sebastiaan.v2
(@sebastiaan-v2)
Active Member
Topic starter answered:
Re: TPU printed tube is air permeable while I need non-permeable

Made some changes and now it works.

Changes:

Temperature - 235°C
Perimeters - 5
Extrusion width for solid infill on 0.60 (rest is all 0.45)
And no cooling this time.

Dont know which is most important but maybe it helps may someone else ever get into this "problem".

Posted : 25/04/2017 11:42 pm
michael.e3
(@michael-e3)
Eminent Member
Re: TPU printed tube is air permeable while I need non-permeable

You can also use a soldering iron or lighter to patch spots if necessary.

Posted : 26/04/2017 12:15 am
danbst
(@danbst)
Eminent Member
Re: TPU printed tube is air permeable while I need non-permeable

Looks like a nice print.
I still can't get TPU to print regardless of what I try. I can get initial extrusion and a reasonable first layer, but then it all goes to spaghetti.
I will punch your settings in and give them a go.
Thanks for sharing.

Posted : 26/04/2017 11:58 am
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