Hi Technet pals :

Flexible circuits have this natural tendency to be flexible . They tend to
springup , bend ,kink & warp due to natural flexibility & handling .

This behaviour is a major headache for the manufacturing engineers during
the assembly process of these circuits - Defects & more defects !
The non-flat nature of these circuits is the root cause of numerous defects
like misaligned , unflush and unsoldered  components . Processes such as
solder paste printing,component placement & reflow oven are not very
resistant to such flexible , warped & bent surfaces . Keeping these ciruits
perfectly flat (like a PCB  ) during these processes is key to eliminating
many of the defects mentioned.

Not to mention that much of conventional automation strategies are not
easily applicable on flex ciruit assembly manufacturing - For example,
automated vision isnpection is an entirely different ball game when it comes
to flexible circuits.

Now the questions :

1) Is there anybody out there who knows techniques of holding the flexible
circuits down real flat ?
2) Are there technologies/vendors in the market who have adhesives
(sheets/sprays/liquids) which can :
        a.      hold down flexible circuit panels flat on a solid pallet
(carrier)
        b.      withstand the reflow oven temperature (max 290 deg
centigrade)
        c.      be peelable/detachable from the flexible circuit panel w/o
causing cosmetic defects on the flex circuit after the reflow process .

Any clues ?


Thanks in advance,
Vishy.

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