Dear Lance:

My sincere apologies for not getting back to you. It was not
intentional. My computer became infected and I had to have the hard
drive reformatted while I was away on a training assignment. As a
result, I didn't get a chance to check my email for about a week. I just
got back on-line yesterday.

I saw your request on TechNet and think you got some very good replies.
Both Dave Chapman and Bev Christian I respect their experiences and
comments a great deal. I would suggest you go with their opinions.

Some of the responders referred to them as disturbed which would be a
defect for Class 1, 2 and 3 per 9.2.4.2. This is where the Standards do
become subjective. There is a difference between disturbed "stress
lines" and lines of demarcation at the juncture between the existing
solder and new solder. I agree with the comments that solder is not
required to spread to the very end of the pads/lands.

So it comes down to how you interpret the lines in the solder connection
whether disturbed or simply "not pretty". If you have a lot of product
being produced this way, you could microsection this connection and have
a metallurgist examine it for a final determination. A disturbed solder
connection is one where the solder molecules have not had an opportunity
to properly align during the cooling process. Therefore, the resulting
wetting may be suspect.

The down side of solder connections is that we infer the internal
wetting to the surfaces being joined (and intermetallic bond between
these two surfaces) by simply examining the external surface conditions.


I hope these comments have be of some assistance to you.

Sincerely,

Gregg A. Owens
Executive Director
Manufacturing Technology Training Center, Inc.
10247 San Sevaine Way, Suite "I"
Mira Loma, CA 91752 USA
Phone: (909) 360-1324
Fax: (909) 360-1346
Website: www.mttc-inc.com

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Lance Mayes
Sent: Tuesday, September 02, 2003 12:16 PM
To: [log in to unmask]
Subject: [TN] pic's
Importance: High


I have attached some pictures of components that always seem to have one
joint that is not soldered as the other end.  These happed mainly with
this component at various sites on the board.  Is this a contamination a
disturbed joint or a cold joint.  This is an SMT process and the
problems vary
on the runs.  I would like to know if this is a defect for class 2 or
not.

Thanks in advance for your time.


                       P.  Lance Mayes
                       Mfg. Trainer
----- Forwarded by Lance Mayes/CO-GRA/Ametek on 09/02/03 01:07 PM -----


Howard Watson
08/27/03 05:33 PM

        To:        Lance Mayes/CO-GRA/Ametek@Ametek
        cc:
        Subject:        pic's




Howard Watson
SMT Manufacturing Engineer
AMETEK/Dixson

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