Today's KNOWLEDGE share:Warpage of a GF filled nylon

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Today's KNOWLEDGE share:


Warpage of a GF filled nylon part is extremely dependent on temperature and moisture uptake.


Temperature increase is responsible for matrix expansion (negligible for the fibers though), and moisture uptake produces matrix swell (again GF does not care much).





So if a part is warped when dry as molded at room temperature (that is what simulation codes will predict for you !!) it will tend to "UNWARP" as you heat the part or let it uptake moisture.


This effect can perfectly be simulated, if you account properly for the anisotropic elastic properties and fiber orientation and know the swell rate with water uptake.

For temperature induced UNWARP you will need detailed Coefficient of Thermal Expansion CTE (T) in x, y and z though to get it right ! Those CTE's, with the needed level of detail, are not available directly from Flow Analysis codes for the moment, but e-Xstream engineering, part of Hexagon’s Manufacturing Intelligence division Digimat software can provide those.


Source:VITO LEO

Visit MY BLOG http://polymerguru.blogspot.com


#plastics #polymerscience #injectionmolding #moisture #glassfiber #nylon #warpage #thermal

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