Hi Rich -

I've encountered this type damage several times over the years.  It has
generally traced to one of the following:

- Board was slid into a card cage and came in contact with a solid
obstruction, such as cage frame, another board, power supply shield;

- Board slid into card cage, hitting another board - determined both boards
were warped to design limit for that particular unit;

- Adjacent board with tall parts slide into card cage, damaging subject
board;

- Board was slid carelessly on a rough surface (presumably by a gorilla
named "Notme");

- Board was in a unit dropped from approximately cockpit height (from
gorilla A to gorilla B, who failed to catch it).  Unit cover bashed open and
cards hit concrete when unit took its second bounce off the aerostand.

I have never encountered this condition as a part of shipping damage with
adequately packed cards or units.

So far as the amount of force required to rip the parts off goes: consider
that the board material specs set some minimum peel strength values for the
foil on the boards.  Your laminate material probably has a T-peel value
(minimum) of around 6-8 pounds per linear inch of width.  This ought to let
you come up with a rough approximation of the force required to create the
damage (generally not a huge number).

Regards - Kelly





-----Original Message-----
From: Rich Lasko <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Wednesday, April 18, 2001 8:55 AM
Subject: [TN] Shipping Damage on SMT components


>Good morning everyone!
>
>I am currently investigating a customer return due to suspected shipping
>damage.  Two components in particular have been damaged.  One component is
a
>SMT bridge rectifier (DF06S) on the primary side of the assembly.  This
side
>uses solder paste and is reflowed.  The other component is a SMT diode
>(DL4007) on the secondary side of the assembly.  This side is glued and
wave
>soldered.  The returned assemblies have either one or the other of the
above
>components "torn" or "partially torn" from the pcb.  Torn includes the
>component, component pad, and attached trace(s) that have been dislodged
>from the pcb.  Both components are located near the edge of the pcb.  It
>would appear that this type of damage would take quite a bit of force to
>dislodge a low profile SMT component from the pcb with the pads and traces
>attached.  The shipping boxes nor static shielding bags appear to have been
>"excessively" damaged.  (No apparent holes, punctures, etc...).  Each
>assembly is bagged separately in a static shielding bag and packaged in
>individual "slots" in the shipping box.  The board size is approx. 4" x 4".
>
>My questions are these:
>
>1.) Has anyone else experienced this type of damage to low profile SMT
>components?  If so, what was the cause and resolution?
>2.) Does anyone have an idea on how much force would be needed to dislodged
>these type components from the pcb?
>
>
>
>Please advise.
>
>Thanks in advance for your responses.
>
>Rich Lasko
>Badger Electronics
>
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