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November 1997

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Subject:
From:
"George H. Patrick, III" <[log in to unmask]>
Reply To:
TechNet Mail Forum.
Date:
Wed, 12 Nov 1997 10:34:35 -0800
Content-Type:
text/plain
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text/plain (54 lines)
KARLA DUGGAN wrote:
>
> We are currently having problems soldering SOT23 parts on
> the bottom side of a board.  We glue the bottom side surface
> mount components and then run through the reflow oven to
> cure the glue.  We then run the boards through the wave
> using both a chip and lambda wave.
>
> All the SMT components solder except the SOT23.  The
> SOT23 is randomly soldered.  Sometimes 2 leads,
> sometimes 1 lead, sometimes all leads, sometimes no
> leads.  The shadowing can be accounted for but not all the
> missing solder is due to shadowing.
>
> Has anyone experienced such problems.
>
> Any help is greatly appreciated,
> Karla Duggan
> APACTS

Hi, Karla...

Assuming wou are talking about wave soldering...

A former employer used to have the same problem on their high
production lines.  We fixed the problem by extending all three
pads by 1mm.

Also, make sure the sot23's are oriented so the body is
perpindicular to the wave.

--

    /\          Praegitzer Design
   /\/\         A Division of Praegitzer Industries, Inc.
  /\/\/\        Portland Design Center
 /\/\/\/\       7245 NW Evergreen Pkwy. #100
----------      Hillsboro, OR  97124

George Patrick, Sr. PCB Designer        Email: [log in to unmask]
Voice: (503) 531-2050 ext. 1813         Fax:   (503) 531-2051

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