One-piece plastic hinge (Strong & Flexible)

Discussion in 'Technologies and Hardware' started by feklee, Feb 12, 2014.

  1. feklee
    feklee Well-Known Member
    Quote from the description of "Strong & Flexible": "When thin, it's flexible enough for hinges and springs."

    By hinge, I assume a bendable plastic piece is meant. For a use case, see the attached image (source: pixabay, public domain).

    Is there any example for such a hinge printed in "Strong & Flexible"? How thick should the plastic be so that it can bend, etc.?

    lunch-pail-225925_1280.jpg
     
    Last edited: Feb 12, 2014
  2. mfoster3
    mfoster3 New Member
    Well as a minimum you could go with the minimum wall thickness for Thin and Flexible which is .7 mm. The width of the hinge segment would probably also be important as well as the transition from thin to thick so that the strain is distributed in a way that reduces fatigue failure.

    Protomold has a design tip here.

    Their example is intended for polypropylene but it gives you a place to start.
     
    Last edited: Feb 14, 2014
  3. feklee
    feklee Well-Known Member
    @mfoster3, thanks for the pointer to the Protomold article! It provides the technical term: Living hinge

    Today I received the Material Sample Kit, and this gives a good impression concerning what is doable, especially since "Strong & Flexible" is also the material for the holder of the samples.

    By the way, I don't want to design something as extreme as the pictured lunch box. My hinge would just need to be bendable by 22.5° in each direction, to allow a total movement of 45°.
     
    Last edited: Feb 14, 2014