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30th April 2022, 07:33 PM
#1
Injection Molding - Grivory Resin
We are processing a grivory GTR45 resin. We process at 485-500 F, dry material to <.1%. Hot runner 2 cavity mold.
Material is a salt and pepper mix, color is blue
Parts receive electronic components, potting, and a glass bonding process.
Uv Curable adhesive, with 175 degrees F UV light to activate the acrylic adhesive. then full UV Cure @ 200 F for 130 seconds
Issue(s)
1. We have seen lubricant "leach" out of the resin when exposed to heat.
2. We have seen glass bonding issues
3. We have seen field failures where moisture reaches the electronics and fails the unit.
4. We have RCA of water ingress through 2 points of entry, the cable port and the glass bonding.
The resin is changing state. Meaning that it will swell around the glass area. or
It will change and over time almost look like a short shot. in a couple of areas
My research points to Tg low due to mold conditions and moisture at point of molding. Parts stress relieve move from brittle to ductile state
My research points to the acrylic acid in the UV curable adhesive causing the resin to move/change state.
My research points to "plate-out" where the internal lubricants are migrating to the surface or the colorant is not compatible to the resin.
My research points to trapped gases in the material. Evident by test where parts are heated until I see a gas bubble form along a flow knit line.
Can someone offer some added input, recommendations, comments or corrections. thanks
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2nd May 2022, 03:22 PM
#2
Re: Injection Molding - Grivory Resin
Hello,
That is interesting. You have done good analysis here. It just looks like a case of incompatible additives. I am not sure what advice I can give you but it is best that you show your results to the material supplier.
-Suhas
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2nd May 2022, 09:12 PM
#3
Re: Injection Molding - Grivory Resin
Maybe condition the parts in hot water for 24 hours?
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