Reply to:   RE>PCMCIA Boards
Robert:

The disk drive industry has been assembling PCMCIA control boards without
carriers for a couple of years now.  There are a few things to consider in the
presentation of the board to the pick/place and reflow process:

1)  Try panelizing the boards "side-by-side" in a 4-up panel.  This allows for
adequate machine throughput and minimizes the scrap material. 

2)  Consider adding outside tabs along the length of the panel (~0.16" -
0.20").  Most pick/place equipment need at least 0.160" for the belt conveyors
to move the panel from one site to another.  These should be routed off after
assembly.  Also, global fiducials can be placed on the tabs for the screen
printer without taking up precious PCB real estate.

3)  You should leave at least 3 "break-away" tabs between the boards to provide
additional support and minimize panel warping.

4)  Also consider using the chain-belt on the reflow oven, rather than the rail
system.  This would minimize panel drooping and warpage during reflow.  With
the chain belt, a support carrier is unnecessary.

5)  Post-assembly routing is a MUST.  With the size and fragility of components
on such a flexible substrate, manual singulation of the panel is courting
disaster.

6)   Connector installation should be a off-line second operation.  There are
connector insertion equipments on the market that use hot-bar reflow of the
connector ONLY, leaving the rest of the assembly unharmed.  I believe that
Intel and IBM are using this type of equipemnt on their flash RAM cards.

Hope this helps you in your endeavor.

Bill Fabry
Truevision, Inc.
--------------------------------------
Date: 3/4/96 10:26 AM
To: Bill Fabry
From: Robert Willis
As I have posted in the past I am conducting trial on the assembly of PC cards
and would like to hear from any one who is processing 0.5mm cards without a
carrier panel as a support. I do not feel to date that it is possible.

Also I am interest to hear from other engineers who are assembling this type of
thin board for any problems that may have been seen.

Bob Willis
Electronic Presentation Services
2 Fourth Avenue, Chelmsford, Essex CM1 4HA. England.
Tel: (44) 01245 351502
Fax: (44) 01245 496123
Home Page: http://ourworld.compuserve.com/homepages/bwillis
Email: [log in to unmask]



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Date: 04 Mar 96 12:34:13 EST
From: Robert Willis <[log in to unmask]>
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Subject: PCMCIA Boards
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