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Reply To: | TechNet E-Mail Forum. |
Date: | Fri, 12 Mar 1999 15:14:41 +0800 |
Content-Type: | text/plain |
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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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