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
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