here's a couple more cents worth (maybe even cheaper than that) from someone
who's fought with suppliers over solderability testing:
Wanna know if it solders? Do a dip and look using ONLY Rosin non-activated
flux. (Pay no attention to the man behind the curtain who says you can use
mildly activated flux or the same flux as your assembly uses!) And make sure
that the area covered by the solder after dipping EXCEEDS the area immersed
in the solder, i.e. there is active wetting/spreading onto the metal of the
part/board. (I like wetting balance too but this is easier.)
And why would I say that if standards typically are based on coverage only?
Think about your solder processes. What do you want the solder to do? Stay
at the points of contact with the lead? Or make nice fillets as it wets up
the hole and/or over the lead?
Dip and look w/o active wetting is a bogus test. And active (even mildly
active) fluxes disguise serious solder problems in dip and look.
So if you don't have active wetting during assembly you gonna get
bogus/unreliable joints.
Suppliers don't like hearing this. But as one involved in assembly I didn't
like junk joints either.
-----Original Message-----
From: Dave Hillman [mailto:[log in to unmask]]
Sent: Wednesday, August 28, 2002 6:09 AM
To: [log in to unmask]
Subject: Re: [TN] J-STD-001 Solderability test requirements
Hi Guy! Loved the name changes! As to the JSTD-001 solderability
requirements, the simplest action is to require a C of C (Certificate of
Compliance) from the component supplier/fabricator and the most complicated
action is to solderability test every lot. Having a C of C satisfies the
JSTD-001 requirement unless the component supplier/fabricator states in
their product literature that they do not supply components which meet the
requirements of JSTD-002. Any reputable component fabricator takes steps to
insure that the components they are fabricating are solderable - and how do
they demonstrate that? - by conducting a solderability test during
fabrication of the components. The fact that BEMS has historical data
demonstrating no solderability issues supports this (using statistics to
keep product/production costs low - a novel concept). The BASC Quality
Manager's requirement of "get a C of C from all their suppliers with each
lot for the BASC Program stating that the "components have been
solderability tested in the past six months" is way out of line and
represents a lack of understanding on the issue. The BASC Quality Manager
is attempting to only "satisfy the specification wording" and not finding a
product value added solution that is win/win resolution for the BASC and
the BEMS. If the BASC Quality Manager has doubts of the validity of the C
of C's (the time period is negotiable and at a minimum should be 12-24
months) then the BEMS could conduct a very limited, sample basis
solderability test on a few component types. What type of
assembly/production defects have been documented? Again, if the
assembly/production defects are not related to wetting issues (e.g.
solderability) then what would the purpose be of getting lot specific C of
Cs for the last six months? Definitely not a value added effort. Rockwell
Collins builds Class 3 (High Performance) products, we meet the
requirements of the JSTD-001 specification (with exceptions noted in the
Collins Workmanship Manual), and we use C of Cs for solderability as a
matter of practice. We do conduct random solderability tests on occasion
and for specific problem cases. The BASC Quality Manager needs to
reevaluate his/her position on this issue unless the cost of the product is
not an issue.
Dave Hillman
Rockwell Collins
JSTD-002 Specification CoChair
[log in to unmask]
Guy Ramsey <[log in to unmask]>@ipc.org> on 08/27/2002 07:24:41 AM
Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond
to Guy Ramsey <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
To: [log in to unmask]
cc:
Subject: [TN] J-STD-001 Solderability test requirements
I received the following message, the names have been changed to protect
the innocent.
I was given the assignment to resolve an audit finding from Big Aero-Space
Contractor (BASC) against Big Electronic Manufacturing Service Provider
(BEMS). Hardware for a BASC program is designed at BEMS. This hardware
has been manufactured since the late 1980s. BEMS recently signed a new
contract, which invoked J-STD-001C,but none of our internal standards
were modified. BEMS Engineering andManufacturing were caught off guard
. BASC audited the BEMS facility and an audit issue known as a CRIER was
placed against BEMS. I haveworked with BASC and provided comparison
information on how BEMS meets the intent of the J-STD-001C. Only one issue
remains, but and I'm struggling to resolve it. The remaining issue
involves the J-STD-001C requirement for solderability testing. I
discussed the matter with our distributors, BOW and GHOST. Both our
suppliers said most of the parts we buy are MIL, already tested and don't
need to be tested again. Some of their C of C certify solderability
others do not. Below is the response from the BASC Quality Manager.
BEMS to get a C of C from all their suppliers with each lot for the BASC
Program stating that the "components have been solderability tested in the
past six months" and we will close this out.
BASC Program Quality Manager
So people, here is the requirement
5.2 Solderability Electronic/mechanical components and wires to be
soldered shall meet the requirements of J-STD-002 or equivalent, and
printed boards shall meet the requirements of J-STD-003 or equivalent.
When a pretinning and inspection operation is performed as part of the
documented assembly process, that operation may be used in lieu of
solderability testing.
BEMS maintains that they have historical data indicating that satisfying
this requirement will not improve the process and will add to the cost of
the program.
Any of you out there building under contract to J-STD-001C? How do you
meet this requirement?
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