Posts: 16
From:Nanjing, Jiangsu, China
Registered: Jun 2003

posted September 25, 2003 02:57 AM               

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Who can tell me how to design and manufacture the tube extrusion die of 5 layer, which the thinest wall has only 0.03mm thickness?

What's the best method to extrude such die?

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Posts: 233
From:McHenry, IL USA
Registered: Nov 2002

posted September 25, 2003 07:42 AM               

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You do it very carefully, that's all.

Now, if you tell us the five materials your using, that would be a big help.

Also, have you done rheological profiling on each seperately, and at different shear rates and temperatures and pressures? This would also help.

Co-ex can be tamed, but you need to select the correct resins firsthand.

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Posts: 16
From:Nanjing, Jiangsu, China
Registered: Jun 2003

posted September 30, 2003 03:01 AM               

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5 layers listing:

inner: LDPE 0.4mm thickness;
second: adheresive 0.04mm thickness;
Midlayer: EVOH or PVA 0.05mm thickness;
fourth layer: adheresive 0.04mm thickness;
outside layer: LDPE 0.5mm thickness;

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Posts: 233
From:McHenry, IL USA
Registered: Nov 2002

posted September 30, 2003 08:21 AM               

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I'd suggest you post this under TOOLING in the plastics.com forum. I doubt that anyone will "tell" you how to build it as there are proprietary considerations involved, not only for the die but the extruder itself. It can be done though.

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Posts: 248
From:New Zealand
Registered: Jun 2001

posted October 04, 2003 03:46 PM               

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You might want to take a look at this article in PT on multiwall tubes and cables. http://www.plasticstechnology.com/articles/200102fa1.html

Steve H

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Posts: 29
From:Fremont, CA USA
Registered: May 2002

posted October 09, 2003 03:25 PM               

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quote:

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Originally posted by chenzhiqiang:
5 layers listing:

inner: LDPE 0.4mm thickness;
second: adheresive 0.04mm thickness;
Midlayer: EVOH or PVA 0.05mm thickness;
fourth layer: adheresive 0.04mm thickness;
outside layer: LDPE 0.5mm thickness;

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With out getting into specifics, I can tell you there are heads out there where you can do this with 3 machines and use A-B-C-B-A distribution.

I have worked with up to 9 layers with multiple arrangements in tubing with total wall thicknesses of < .0015" and diameters as low as .020".

Your smallest crossection is still over .001", so it should be a piece of cake!

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