Doug:

Not flux/solder related, so slightly off topic:

While keeping up with developments in J-STD-001, we're continuing to work to
an internal spec based on MIL-STD-2000A.  For our Class 3 mix of military,
space, and commercial products, we've told our customers that we don't see
many advantages in the J-STD, and I think it's gotten worse in the latest
rev.

        1.  As for general philosophy, there are more "thou-shalts" in the
J-STD than you're giving credit for.  Just for example, defect 1 is for
"Hardware found to be manufactured with nonconforming materials or
processes."  This means that you are required to reject and disposition all
hardware where specific process violations have been found.  Taking this to
the point of absurdity, someone could take a position that if an operator
sneaks a piece of candy (violation of Paragraph 3.6) then all of the
hardware in the "work area" must be rejected.  If an operator's static mat
is found to have a marginal ground during periodic testing (violation of
3.5), we might have to track down everything produced at that workstation
since the last mat test, including hardware already shipped, and disposition
it somehow.  Under MIL-STD-2000A, we treat these as process control
violations, and evaluate the potential harm to the product before we reject.

        2.  I'm uncomfortable with the ambiguities in the J-STD.  I get the
feeling that there is little consensus in industry as to how it should be
implemented.  Many consider this a strength of the document, but with our
customers, I worry that it leaves too much room for interpretation to the
auditors, who (in rare instances) can be ill-informed, opinionated, and
capricious.

        MIL-STD-2000A says that you must inspect for everything and
"document the occurrence of all defects and variances."  J-STD-001 very
pointedly does not say this, but what are we really obligated to do?  If
you've adopted J-STD-001B or C for Class 3 - what do you inspect for?  Do
you train all of your inspectors for every condition described in the
document?  Do you inspect for everything, including the process indicators?
Does anyone really verify the "side joint length" of a solder joint as it
extends under an LCC (dimension D in Paragraph 9.2.6.7)?  Are all of the
findings documented and used for process control?

        3.  J-STD-001C is the most stringent version yet.  MIL-STD-2000A has
a minimum of 20 defects, but the J-STD continues to balloon.  Depending on
how you count them, Table I has at least 36 defects now, surely many more if
you look at all the paragraph references.  I believe that some of the Class
3 people on the committee are unwilling to tailor the requirements to their
own needs, and have lobbied to put all of their particular prejudices and
customer expectations into the spec.  This ratchets the document toward more
and more stringent interpretations.

We have implemented MIL-STD-2000A through a tailoring document which
interprets the requirements, and in some cases is somewhat tighter.  This
allows us to claim in good conscience and legality "Yes, we comply, and then
some".  Does anyone out there really "comply" with J-STD-001?  Or am I
missing some wording in the spec that allows you to pick and choose which
requirements you want to adopt, and still claim compliance?  Or is this
really a guidance document after all?

Joe Kane
Lockheed Martin Control Systems

> ----------
> From:         Douglas Pauls[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;[log in to unmask]
> Sent:         Friday, May 05, 2000 12:15 PM
> To:   [log in to unmask]
> Subject:      Re: [TN] J-STD-001 implementation from Mil2000
>
> In a message dated 05/05/2000 9:45:18 AM US Eastern Standard Time,
> [log in to unmask] writes:
>
> > What are the material impacts of moving to J-STD-001 from the
> Mil-Std-2000?
> >  Specifically, solder and flux, would procurement of new materials
> certified
> > to J-STD-00X be required or can QQ--S-571/Mil-F-14256 materials be used?
>
> Richard,
> This is far too broad a question to be answered reasonably here.  You
> still
> have to understand the materials and processes that you are using.  You
> still
> have to do testing to demonstrate that your materials are compatible with
> each other.  You still have to produce hardware that meets your customers
> requirements.
>
> In my estimation, the biggest difference between J-STD-001C and
> MIL-STD-2000A
> is the philosophy.  MIL-STD-2000A was the last of the "thou shalt do it
> thus
> and so, or else" specifications.  J-STD-001C is predicated on the "we
> don't
> care how you make it, it just has to work to our specifications" approach.
> It does not specify what kinds of testing you have to do to demonstrate
> compatibility.  That's up to you.
>
> You need to use a flux/paste/cored wire solder that is qualified to
> J-STD-004.  If you choose to not use a flux/paste/cored wire solder that
> is
> not qualified to J-STD-004, you have to have objective evidence on fhand
> that
> the combination is compatible and not detrimental to reliability.  So the
> question of "can I use material X" can be answered with "sure, provided
> you
> have the data to back it up".
>
> I did a paper in years past on qualifying a process to J-STD-001B, and the
> approach is still pretty much the same for the C revision, although I am
> currently reading through Rev C to make sure of this.  If I recall
> correctly,
> I turned it over to IPC as a white paper.  It was titled "The Layman's
> Guide
> to Qualifying a Process to J-STD-001B".  It might answer some of your
> questions.
>
> Doug Pauls
> Technical Director
> CSL
>
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