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May 2000

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Subject:
From:
Gary Camac <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 18 May 2000 10:26:17 -0500
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Ed,

I have never tried a return-to-web panel on SMD assembly.  We have processed boup coup
CEM-1, single-sided, through-hole panels.  Sometimes the individual PWBs are not pressed
back completely flush with the web.  This is probably not going to cause you a problem at
placement.  Stencil printing could be a problem, depending on which side you are going to
populate. If the individual boards sit a little high - probably no big deal.  If the
boards sit below the web, printing could get ugly, as in extra paste getting deposited and
turning into the odious solder short.

Another problem might be the bow.  Typically this type of panel bows.  The more individual
boards that punched out of a panel - the more the bow.  After punching the board is
slightly bigger and the hole is slightly smaller, because punching does not leave a clean
line of separation.  When the board is  returned to the web, its like putting 6 lb.. [2.72
kg] in a 5 lb.. [2.27 kg] bag and things start bulging.

Just some thoughts,

Gary Camac

Ed Holton wrote:

> Is it possible to print, populate and reflow a punch and return style PCB.
>
> Ed Holton
> Manufacturing Engineer and Group Leader
> Hella Electronics
> Telephone (734) 414-0944
> Fax (734) 414-0941
>
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