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February 2007

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Subject:
From:
"Victor G. Hernandez" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Thu, 1 Feb 2007 11:50:01 -0600
Content-Type:
text/plain
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text/plain (116 lines)
What caused the mechanical damage to the solder mask surface?
Can we see a photo of a mounted heat sink.
How many leads are attached to the PWB?
Can the upward motion cause tensile pull on the lead?

Victor,

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
Sent: Thursday, February 01, 2007 11:35 AM
To: [log in to unmask]
Subject: Re: [TN] Mechanical Stress on solder joints

Hi Gary!

I have your picture posted. It's at:
http://stevezeva.homestead.com/files/Broken_Pin.jpg


It sure looks like something has pulled or stressed that pin. I'm trying
to visualize the heatsink, but I can't form a mental picture of it, so I
can't say for sure if it was the heatsink or not. But from your
description, it seems pretty probable that the stress that you describe
damaged that pin.

-Steve Gregory-

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Bremer, Gary
Sent: Thursday, February 01, 2007 10:02 AM
To: [log in to unmask]
Subject: [TN] Mechanical Stress on solder joints

Gentlemen,

 

I have a device that failed in the field, the part is a DC/DC converter
that is first soldered to the circuit board then a massive heatsink is
screwed to the converter pulling the device upward because of an air gap
not covered by a thermal conductive pad. Could this be the cause of
damage to the component pins as shown in the attached photo? The solder
used is Sn63 on the circuit board side and the mass of the board solder
joint appears to be twice that of the component.

 

Gary Bremer
Senior Manufacturing Engineer, CIT
  
Curtiss-Wright Controls Inc. 
Embedded Computing -Subsystem

28965 Avenue Penn
Santa Clarita, CA 91355-4185
Main: 661.257.4430 extension 2170
Fax: 661.257.4782


e-mail: [log in to unmask]
Web: www.cwcembedded.com 

NOTICE: This e-mail communication is private and confidential and is
intended for the addressee only. The email may only be used for
conducting business with VISTA Controls Inc., dba Curtiss-Wright
Controls Embedded Computing Subsystems. If you are not the intended
recipient, please notify us by replying to this email followed by
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