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Recent content by injectionmolder

  1. injectionmolder

    cleaning injection mold screws & barrels

    For this purpose, all methods work, some better then others however. Which one is the most inexpensive, I will say is the question. Pulling the screw it is the most efficient while the most expensive. As one member pointed, wet PP works fantastic and cost almost nothing. Cast acrylic it also...
  2. injectionmolder

    Losing pressure on Shut-off nozzle

    We have needed more information however, assuming we are talking about a double barrel press therefore with two nozzles and shut off systems. First check the source of heat for the defective nozzle. A defective heater band near the shut off system could give us that kind of problem. If that...
  3. injectionmolder

    Automotive plastic finishing

    Try Society of Plastics Engineers www.4spe.org You might be able to find the needed information, it won't be for free but there's. Regards
  4. injectionmolder

    Injection molding- cooling time vs. melt cushion

    Sure there is a relationship between cooling and the cushion. On semi crystal resins, we can increase melt temperature by decreasing screw rpm. As for amorphous polymers, melt temperature increases with higher rpm. Nylon is a semi crystal. With that said, will pretend a recovery time of nine...
  5. injectionmolder

    Bronze Mold Inserts, any alternative materials?

    Engineer983 has a point by fixing the robot properly. Even if we find a stronger and inexpensive material that is hard to imagine, eventually the area of the robot that contacts the mold will get damaged. What I will do if the inserts currently need replacement, is going to aluminum as...
  6. injectionmolder

    multi cavity moulds

    Family tools the devil of the plastics shop. I have found that if possible and done right work better by balance the runner according to the thickness, and gates to be kept the same size. However, still a nightmare to get to a profitable production level. Regards
  7. injectionmolder

    bubbles in PC

    Try to use injection profiles since this definitely sound like you are going from a thin wall, to a thick section as the cavity is fill. Boost as fast as you can until you are getting into the thick wall, then slow dramatically down with higher pressure in order to maintain low speed followed by...
  8. injectionmolder

    Nylon overmoulding

    A vacuum is a good idea that will allow you to have faster injection time, no problem if the tool has some venting issue’s vacuum will take care all that. However, it will not help you at all if your polymer is wet at the time of the injection, or if you have any of the problems that were...
  9. injectionmolder

    Injection molding tooling cost?

    Keep in mind that your production volume will be a factor on how much you can save, if your production will be extremely high do not make any mistake in things such getting a hand load insert tool just to save without getting a core pull tool. You might end up paying for the core pull and more...
  10. injectionmolder

    Plastic injection mold temp control

    Oil should only be used for resins such as Polysulfone, Ryton, Ultem, polymers that require high heat. Processing ABS even with lower heat, but running oil just don’t seem right. I know water is no longer an option in your company however, seems to me your problem with corrosion was originated...
  11. injectionmolder

    Nylon 6-6 resin (glass reinforced)

    Patprimmer is exactly right, sure sound like your problem is the check valve. What about your molded parts? If you are running a natural resin do, you see any burning at all? That will be an indication of the mentioned problem. Also is your part weight going up and down? Before you get to pull...
  12. injectionmolder

    Large part mfg problem

    Pre production plastics in Corona CA (no affiliation to this place) They have presses with up to 25 pound shot, structural foam, gas assist, and injection molding, just what you might need for that size of part. Regards
  13. injectionmolder

    Source for Lexan resin?

    Hi bassnut On your previous question you were talking about some craters kind of like orange peel on your parts, or at least that’s the way I understood. Splay now, I am assuming is a different issue right? Now just like patprimmer said, get some good drying equipment so that you can dry your...
  14. injectionmolder

    Surface Finish On Polycarbonate

    Hi bassnut Ask your molding supplier what happens if the following are increased: melt temperature Tool temperature Injection pressure Injection velocity At the same time be care full not to over pack the cavity, but see sounds to me like this has to do more with the way they are injection the...

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