Stress Cracks in Noryl
Stress Cracks in Noryl
(OP)
I have a problem with a part that we have been using for years. We are installing Helicoils into a machined Block of Noryl. We are constantly getting cracking around the helicoils. None of the rest of the features in the part show any stress cracking.
Note we see the cracks before any screws are fastened into the Helicoils.
Any idea what could be causing this problem? I know that Noryl should be machined with non-hydrocarbon based lubricants. I checked with our machine shop and they are using a semi-synthtic. Is brittleness in Noryl a side affect of using a hydrocarbon based cutting fuid?
Thanks





RE: Stress Cracks in Noryl
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Jason Williams
K Development, Inc.
RE: Stress Cracks in Noryl
Have you contacted your local GE Plastics rep? Try this website...
http://www.geadvancedmaterials.com
--Scott
For some pleasure reading, try FAQ731-376
RE: Stress Cracks in Noryl
NORYL is a blend of PPE and polystyrene. The polystyrene component is what the solvents attack. Some NORYL grades have glass fibers which will make the material stiffer but also more brittle.
Mike