Rigid Flex and Flex

SUMMARY

• Up to 16 layers Rigid flex

• Sequential laminations

• HDI up to 8 layers

• Flex with Air Gap

FLEX CIRCUITS

• Flex are in use since the 50s

• The Flex is an insulating Polymer and a layer of Copper for circuitry

• 1- 6 layers 0.5oz – 1 Oz copper

• Multiple Stiffener per circuit

• Etching and plating constraints are similar to Rigid PCBs

 DESIGN CONSIDERATIONS

• Traces should be perpendicular to bend axis

• Keep trace corners, width changes and via out of bend area

• Thick copper traces if possible

• Fillet pads

RIGID FLEX VS FLEX WITH STIFFENER

  * Multi layer flex combined with Flex

  * Flex with Stiffener ( FR-4) as alternative to rigid flex when possible

  * Flex with stiffener ( polyamide)