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June 2007

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Subject:
From:
"Stadem, Richard D." <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Stadem, Richard D.
Date:
Mon, 11 Jun 2007 15:29:19 -0500
Content-Type:
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Totally agree. I was just trying to point out that there is definitely
criteria available to identify a defect that can be described as
insufficient, poor wetting, de-wetting, nonwetting, open, etc. The
specifications do not mention "open solder connection" or other obvious
defects that result from not meeting the criteria either. That does not
mean that the term "insufficient solder" is not covered by the standard.


My other fear is that someone who is not knowledgeable would assume that
insufficient solder was not a defect covered by J-STD-001 or 610 if they
read your note.

All of these defects, no matter what you call them, disappear if the
solder joint criteria as shown (and quantified) in the J-STD-001D and
IPC-A-610D are met. If there are particular circumstances where the
non-conforming condition or desired solder joint are not covered by the
standards, then acceptance criteria should be defined in some type of
in-house document (Corporate Workmanship Standards) that provide the
desired acceptance criteria for the inspectors/operators.

If an inspector is fully trained to judge solder joints by the criteria,
he/she should be able to detect the non-conformance and flag it. It does
not really matter what the inspector CALLS the defect, the important
thing is that it does not meet the spec. Unless you have trained
inspector(s) who function as "Da Judge", you end up with all kinds of
different judgement calls amongst untrained and uncertified operators,
and hence uncontrolled rework. Rework needs to be confined to only the
defects that do not meet the criteria, and you need a good
inspector/quality control/quality engineer to do that. Else there is no
way to control excessive and unnecessary rework and touchup.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Glen Herzog
Sent: Monday, June 11, 2007 1:31 PM
To: [log in to unmask]
Subject: Re: [TN] Insufficient Solder

Richard,

I am certainly glad you didn't find the term "Insufficient Solder" in
any of the citations that you offered.  I'm also glad that you're only
disturbed by the throw away line.  

I have seen people identify many of the defects that you pointed to plus
dewetting, nonwetting, and minimum acceptable solder, as "insufficient
solder."  My real message was that you need to be very careful when
putting an Inspector in charge of determining when product must be
repaired and even worse, when product lines must stop. Besides I think
that you could find each of those defects specified, while they might be
caused by insufficient solder, might also be caused by something other
than "insufficient solder."  


-----Original Message-----
From: Stadem, Richard D. [mailto:[log in to unmask]]
Sent: Monday, June 11, 2007 1:09 PM
To: TechNet E-Mail Forum; Glen Herzog
Subject: RE: [TN] Insufficient Solder


Boy, oh, boy, I have to take exception with the statement: 

"Incidentally, I don't think that the term "Insufficient Solder" is in
either standard.  I think that it is just a general term that we often
use without much definition."

The minimum amount of solder forming a fillet around the unsupported and
the plated-through-hole lead is clearly defined for each class in
section 6.1 and 6.2. The minimum amount of solder hole-fill is defined
for each class in section 6.3.2 in J-STD-001D The minimum heighth of the
heel fillet for gullwing leads is clearly defined for each class. See
section 7.6.7 and Table 7-7. The minimum endcap fillet for chip caps and
resistors is clearly defined for each class. See Table 7.4 The minimum
amount of LCC fill is clearly defined. See figure 7-6 and Table 7-6. The
minimum amount of solder required for MELF terminations is clearly
defined in Table 7-5.

And so on and so forth...

Anything not meeting the minimum is insufficient solder.

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Glen Herzog
Sent: Monday, June 11, 2007 12:12 PM
To: [log in to unmask]
Subject: Re: [TN] Insufficient Solder

Ron,

Your question, "Does anyone here have a sure fire way to combat
insufficient solder."  apparently has two interpretations (1) how do I
get sufficient solder and (2) What should my inspectors do when there is
insufficient solder.  I'll try to address the inspector issue.

Normally, inspectors do not cause rework.  They have criteria from
J-STD-001 and ANSI/IPC-A-610.  Based on that criteria they will
determine if an assembly passes or fails the criteria.  Unless that
Inspector is quite experienced, a Quality Technician or Engineer, or a
Process Engineer determines what action must be taken.  Often
"Insufficient Solder' is a process indicator.  The process needs
improved, but the board does not need to be reworked.

Incidentally, I don't think that the term "Insufficient Solder" is in
either standard.  I think that it is just a general term that we often
use without much definition.

Good Luck, Ron

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