flex circuitsDesigning of a flex circuit has to take into consideration the “mechanical” aspect of bending and potentially cycling the circuit. Other mechanical aspects that affect a flex circuit are size and shape, thermal properties, and mechanical stability in key areas. Below are high level “rules of thumb” for a static and dynamic circuits. Additionally, you can search our site for data that covers reliability, stiffeners, and materials.

Static (One-time Bend)

  • Rule of Thumb, Bend radius for flex to install is 10x the thickness of the flex this can often be pushed to 5x.
  • Can use stiffeners to create a natural folding configuration.
  • Keep stress concentrators well away from bend areas.
  • A soft adhesive system may “pucker” on the inside of a tight bend radius.

Dynamic (Multiple Bends)

  • Rule of Thumb, Bend radius for dynamic flex is 100x the flex thickness.
  • Conductor thickness and width should remain constant in bending areas.
  • Conductors should be staggered from layer to layer and not stacked on top of each other to increase flexibility.
  • Conductor thickness and width should remain constant in bending areas.
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