Vishy,

GSC makes several variety of fixtures to hold flex circuits flush and flat
during the smt and other assembly processes. We can utilize a number of hold
down techniques depending on what will type of flex circuit you are working
with. Give me a call and I'll see if we can help you.
Jim Gleason
GSC
972-494-1911
www.gogsc.com

-----Original Message-----
From: Narayana Vishy-CVN002 <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Friday, March 12, 1999 1:18 AM
Subject: [TN] Flex circuit flatness - Is the solution out there ?


>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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