Tek-Tips is the largest IT community on the Internet today!

Members share and learn making Tek-Tips Forums the best source of peer-reviewed technical information on the Internet!

Register Log in
  • Congratulations TugboatEng on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Recent content by dhuffy

  1. dhuffy

    Cow's horn or 270¦ gate vendors

    There is another supplier called iMold (www.imold.com). I think they spun off of the Exaflow company, or vice versa...can't remember. Give them a call to see if they can help you. dhuffy
  2. dhuffy

    Santoprene part not shrinking enough length wise.

    Hello Dave, Yep, I would suggest a warmer hotter melt temperature (more heat gives the material more time to shrink). Good luck. DHuffy
  3. dhuffy

    multi cavity moulds

    I also strongly discourage family molds. I ran them in my previous job and hated every minute of it. But at times they are an evil necessity. They can be done successfully if certain guidelines are followed, especially regarding the amount of non-similarities between the parts being molded...
  4. dhuffy

    Stack mold / Family mold

    It is true family molds causing filling problems. But if they are designed properly they can be run successful. We have helped several companies design/run family molds successfully. The problem you mention is most likely due to the design of the hot runner system in that it does not account...
  5. dhuffy

    How do you increase weld line strenth in GF LCP resin moldings ?

    From your description, I presume the part is some type of connector since you are using LCP. But in either case it is difficult to achieve a higher weld line strength. I would not recommend a hot runner for LCP material and this type of application, and multiple gates may only increase the...
  6. dhuffy

    balanced runners

    In addition to my previous post (because I could not figure out how to edit it, hehe), simply changing runner sizes will create a pressure balance at best that MAY work for one given process and material lot. If the pressure in the system changes for any reason (different injection rate...
  7. dhuffy

    balanced runners

    Simply visit www.meltflipper.com for an indepth explanation on why you see filling imbalances on geometrically balanced runners. Basically it is shear creating different material properties that flow to certain cavities in multi-cavity molds (which is not always the inside cavities - it depends...
  8. dhuffy

    NEED PLASTIC GEAR DESIGN BOOK

    I would also suggest contacting AGMA (American Gear Manufacturing Association - or something like that). Search them on the web and they should be able to help you. Dave
  9. dhuffy

    Plastics training and consulting

    I would also suggest talking to the people at the Penn State Plastics Technology Center. You can read about and contact them from http://ptdc01.bd.psu.edu/. Dave
  10. dhuffy

    Bend But Don't Break

    iwmob, It seems you would be asking for alot out of a GF nylon. I don't think you would be able to bend that material at all without it breaking, even if you do so right out of the mold. You would need to heat the bend area in order for it to even have a chance at working - and even then it...
  11. dhuffy

    Can I get a 'bubble' effect in Trans ABS?

    tinari, You probably want to look at adding a blowing, or foaming, agent to the material. You can do a quick search for suppliers on the net or some others in here will probably give you some good references. Have fun. Dave
  12. dhuffy

    Non destructive testing/inspection for voids in plastic moulds

    Hmmm...this could be a tough one. You did not mention the material. Is there a clear version of the material you are using? If so, try molding it to help verify the changes in the molding process and elimination of the voids. Then go to the colored material and see if the changes hold for...
  13. dhuffy

    This equation from the Injection molding handboook(Rosato)

    Kes, The equation is for the injection molding process if you want to calculate the minimum ESTIMATED cooling time for a given part. From the equation, you can see it is asking for the thickness of the part you are molding, the material properties and for information about the process (mold...
  14. dhuffy

    balanced runners

    As for the cooling effects on balance, there have been studies done where the inside cavities are cooled and no cooling on the outside cavities to try and reduce imbalance since it was once thought that a thermal imbalance existed in the molds and that created the imbalance. It sounded good and...
  15. dhuffy

    ballanced runners

    Sorry to respond to late in the game, but I just recently visited the forum again. I appreciate the kind words some have spoken on MeltFlipper technology. The imbalance in multi-cavity molds can be explained in detail by visiting www.meltflipper.com. Please visit the site and send me an email...
See more

Part and Inventory Search

Back
Top