We are doing a lot of wetting balance testing for customers with
soldering problems. Many companies are purchasing through distribution,
sometimes the components have been around a while. Even factory direct we
see issues with solderability. Remember some of these factories are not local.
It is amazing what a couple of weeks at sea will do to a component. And that
line haul trucker, the guy with leaking door seal on his trailer, will he be
able to repack the stuff well enough to pass it off at the distribution
center?
Foremost, in our minds is profit.
Sadly, some
manufacturers are in serious recovery mode, having produced significant
quantities of product with non-conforming material and potential reliability
problems.
Consider the portion of the J-STD-001 that addresses defects
related to Material and Process Non-conformances:
Hardware found to be produced using either materials or process that do not conform to the requirements of this standard shall be disposition when the condition is a defect listed in the applicable text box. This disposition shall address the potential effect of the nonconformance on the functional capability of the hardware such as reliability and design life (longevity).
Note: Material and process nonconformance differ from hardware defects or hardware process indicators in that the material/process nonconformances often do not result in an obvious change in the hardware's appearance . . .
Anyone who has been involved in electronic
manufacturing, even briefly, will have struggled with these issues. It is much
more difficult to face the consequences honestly, when the product looks okay,
but you know it's not.
We hear from links in the supply chain that
developed and relied on the old Mil Standards. Frequently, they complain that
the consensus standards are too relaxed. I think the J-STD-001 requirements for
Solderability and Solderability Maintenance provide appropriate rigor and
flexibility, when properly interpreted and applied.
Guy Ramsey
Senior
Lab Technician / Instructor
E-Mail: [log in to unmask]
Ph: (610)
362-1200 x107
Fax: (610) 362-1290
-----Original Message-----
From:
TechNet [mailto:[log in to unmask]]On Behalf Of Stephen R.
Gregory
Sent: Thursday, July 05, 2001 8:18 PM
To:
[log in to unmask]
Subject: Re: [TN] J-STD-002 and -003 solderability
testing...
Okay, I know I'm going to piss some people off...I'll test
components from
AVX, Murata Erie, Kemet, Vishay, Texas Instruments, Amkor,
Signetics,
National Semiconductor, Fairchild, Motorola, etc...etc...and
then I'll find
that everything is okay... DO YOU THINK THIS IS NECESSARY? BE
REAL!!!!
Don't you think that solderability is foremost in the vendors of
these
components? Do you ACTUALLY think that we have to double-check what
they say
they are going to provide to us? That we have to check everything
they
provide to us?
I'd like to hear from component manufacturers...do
we need to check your
stuff? If we do, I would be ashamed....
-Steve
Gregory-
J-STD-001C 5.2 Solderablity: Electronic/mechanical
components and wires to
be soldered shall meet the requirements of J-STD-002
or equivalent . . . I
do not see a requirement for 100% solderability
testing. I am not a
proponent of 100% solderability testing.
I submit
that the standard requires you to "know" that the part you intend
to use in
production be solderable as defined in J-STD-002. I believe you
can "know"
this through statistical methods and sampling.
I set up a sampling plan
for our board suppliers that specified sampling by
date code. So, in the case
where our supplier manufactured many different
part numbers our testing
requirements were reduced. We found the system to
be effective (identified
defective product and minimized inspection and
test), and our customers
approved the system.
I think the part of the standard that might be
getting you is 5.4
Soderability Maintenance: . . . ensure that all
componets, parts, leads,
wiring . . . are solderable.
But, I interpert
this paragraph as addressing storage and handling. It does
not mention
testing or inspection. This paragrah requires the manufacturer
to "know" that
storage and handling has not degraded the components to
be
soldered.
The end item acceptability criteria in the J-STD-001 and
IPC-A-610 assume
that the materials and methods used conform to the
requirements of the
standard. This is not a version of process control it is
a prerequisite for
compliance.
A means by which we can provide
assurance is SPC, rather than 100%
inspection. One of the four essential
techniques in Statistical Quality
Control (from the Western Electric
Handbook, 1956 based on Shewhart's work)
is Statistical Sampling
Inspection.
Guy Ramsey
Senior Lab Technician /
Instructor
E-Mail: [log in to unmask] <mailto:[log in to unmask]>
Ph: (610)
362-1200 x107
Fax: (610) 362-1290