Check solderability of the component terminals. 
If the part does not accept solder well it may float off the pad before it
begins to wet. But, I would expect the part to shift to the side too. 

Guy

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Russell Nowland
Sent: Friday, June 19, 2009 11:32 AM
To: [log in to unmask]
Subject: [TN] Float Electrolytic Caps

Hello everyone,

I have an entering situation that my EMS has not been able to figure out.

We use several SMT Electrolytic Capacitors that are sliding off of the pads.

The pad design is per the recommended my the device suppliers and also 
comply with our normal design parameters.  The issue is the device wants to 
slide toward the heel and toe so you end up with pad overhang and clearance 
issues.  The pad design is narrow enough that it is not twisting.

My EMS's current solution is to apply a couple of glue dots under the device

to secure it before the solder reflows.  I am not real crazy for this
process for 
several reasons but they asked permision and it does not violate any 
requirements.

Have any of you seen this and how are you handling it?  Hopefully without 
glue.

Thanks

Russ Nowland

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