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  1. gao7857

    High stiffness plastic (unfilled) for injection molding

    Chris, That sounds promising. Do you happen to know a compounder of a supplier that compound phlogopite into the plastic? Or a commercial plastic grade that is filled with phlogopite. Thank you! Gao
  2. gao7857

    High stiffness plastic (unfilled) for injection molding

    Chris, What particle size and aspect ratio can phlogopite mica be?The small component is less than 1 cm and the small texture is about 1mm. For the large component we currently trying very long fibers that can can throughout the part dimension. Cory, Thanks for reminding. I do need different...
  3. gao7857

    High stiffness plastic (unfilled) for injection molding

    Hi There, I am looking for a high stiffness material that can be injection molded. Actually I try to use fibers to bring up the plastic strength several folds to close to that of soft metal, but a small component of this product cannot be reinforced by fibers. This component need to hold the...
  4. gao7857

    fire rated aluminum tube or sheet

    Thanks Al. So there is no chance aluminum pipe/conduit can withstand the fire. The conduit is not a structural part though, as it only houses the cables.
  5. gao7857

    fire rated aluminum tube or sheet

    Hi there, I am looking for a fire rated aluminum tube or sheet metal that can pass fire test such as UL2196 or NFPA130 or NFPA502. I am not a metal person and after googling I could not find an answer. Please recommend a aluminum that can do this. Thanks. Or a treatment that can help aluminum...
  6. gao7857

    4" to 6" dia pvc coupling

    Pud, Thanks for the comments. I agree the gate size is small, maybe 2.5mm is still too small... It is totally about 200mm long, 22oz part that filled at 3.4oz/s by the molder. I have to increase the gate size (and perhaps the runner and sprue too), so that I can reduce fill time without cause...
  7. gao7857

    4" to 6" dia pvc coupling

    Mike, The gate is at the large periphery near to the joint region to try to balance the mass. It is not at the joint as we think it may weaken the mechanical strength at joint. There are ribs on the small outlet that make it mass'ier than the large outlet side of the gate. Are you saying to add...
  8. gao7857

    4" to 6" dia pvc coupling

    This coupling is connecting a 100mm pipe to a 150mm pipe. The contract molder was using a 280ton JSW (max rate 32oz/s) to mold the single cavity mold, with the circular gate (2mm at part) at the larger outlet surface. The thickness is about 5mm for both outlets except the joint a little thicker...
  9. gao7857

    Plastic degradation near sea when assembled with metal part

    Btrueblood, Yes nylon66 is one of our plastic parts that had this issue. Which types of polyamide is resistant? pa12? because of how it is polymerized? I assume fluoropolymers are immune to this mechanism? Thanks.
  10. gao7857

    Plastic degradation near sea when assembled with metal part

    It can be used in both coast or mexico, but mostly found in west coast.
  11. gao7857

    Plastic degradation near sea when assembled with metal part

    Plastic can be nylon or PC, metal is tin or zinc plated iron
  12. gao7857

    Plastic degradation near sea when assembled with metal part

    Hi, I noticed the plastics are likely to degrade easier/quicker near sea (or in sea water) when it is in contact with metals. I feel there are some electrochemical activities going on. Can anyone help me understand this phenomenon, and is there any literature discussing it? Thanks! The plastic...
  13. gao7857

    Plastic degradation near sea when assembled with metal part

    Hi, I noticed the plastics are likely to degrade easier/quicker near sea (or in sea water) when it is in contact with metals. I feel there are some electrochemical activities going on. Can anyone help me understand this phenomenon, and is there any literature discussing it? Thanks! The plastic...
  14. gao7857

    Where can I find a good overview for popular coating materials and methods?

    TomDOT, Thanks for your suggestion! It is quite good a series of reading after reading the descriptions. I was trying to find the table of contents of the books but cannot find it for any one of them. Is the book written by the author in chapters systematically? or is edited by the author from a...
  15. gao7857

    Where can I find a good overview for popular coating materials and methods?

    Thanks. I am new to coating materials and methods. But our product has recent need to get new coating material and method. So I am trying to get myself educated a little more besides my basic chemistry and polymer knowledge. Our product is zinc galvanized steel part. There are so many coating...
  16. gao7857

    How to quickly measure the brittleness of a plastic?

    The part is an electrical component, Yes the part can be used in desert for solar equipment. But with DAM we are quite aggressive on our QC, as even in desert the RH may never be zero. It is however one way we want to make a better product. We do have product made of PA12 though, but that one...
  17. gao7857

    How to quickly measure the brittleness of a plastic?

    Thanks Chris for the comment. We currently add water to it. We have two tests for brittleness, one is dry as molded, another is moisturized; as the part can be used dried or moisturized. The moisturized one is fine, while the DAM parts have large variations on the brittleness, and at different...
  18. gao7857

    How to quickly measure the brittleness of a plastic?

    We have a sort of modified izod machine to test it, but we are asked to find an easier and faster way. There are two challenges as we internnally discussed: one is that sometimes the impacted area may not represent the brittleness of the whole part; another is that the part is quite small. Also...
  19. gao7857

    Expanding Photopolymer

    Gkan, Dr.Demon is right about the contraction. Be ware of the UV if it need to pass a layer of medium like glass or transparent plastics. The UV curing effect can drop a lot. We thought about similar stuff before but was not lucky . That was several years ago though as things may change. There...
  20. gao7857

    How to quickly measure the brittleness of a plastic?

    For the plant, when they process the parts off the process parameters, the plastics got degraded and in my case become brittle for nylon. However many times it looks good until you test the product. Is there a quick way to evaluate the brittleness of a plastic? Thanks. The part is quite small...

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