Apr21
Design for Flex cable(FPC) Trace Pattern

FPCMany FPCB designer are not familiar with the manufacturer process and limitation.  I always found design does not meet DFx requirement and insist on their design and finally bring lot of quality issue after mass production.

Here I ask FPCB supplier provide  some of the design for the flex cable (FPCB)  manufacturing  ability and hope it will prevent future quality fail or cost high due to yield lose.

Basically I do think designer and FPC manufacturer shall make more communication to understand each other requirement and make FPCB lower cost and higher quality and yield rate. This shall be win-win.

1. Relationship between Through Hole, Land, Cover Film, and Cover Coat

Not Recommended

Recommended

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The “Cover Film” must over to the soldering pad to prevent it from peeling off while soldering.

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2. Circuit Pattern Guidance

Not Recommended

Recommended

No sudden expansion or reduction in pattern width. No sharp angle.

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3. Design at Folding Area

Not Recommended

Recommended

  If the FPC need to be folded then the folding area shall be covered with cover film to prevent trace breaking.

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  Avoid folding at below locations to eliminate the possible stress focus
a. The change of pattern width.
b. Folding parallel to the pattern.

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4. Design at Folding Area

Not Recommended

Recommended

  Plating leads and disconnection holes should be designed as illustrated in order to avoid short circuits.

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5. Design at Folding Area

Not Recommended

Recommended

Avoid ending edge locate at same location for each layer.  
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