Hi Genny,
There is no industry standard, everybody is left to figure out their own
problems. As a point of reference, here is what we have done.
(Admittedly, my problem is several orders of magnitude easier than yours
because I have fewer parts and better control over what parts I get.)
First of all, our internal part numbers are not the same as our
supplier's part numbers. So whatever our suppliers do to their part
numbers don't impact us except for what is allowed on the AVL and
therefore procured. This separates part number management into two
groups, managing the AVL and managing the BOM.
First, we added solder paste to the BOM and we set a conversion target
date whereon we would no longer accept leaded parts from any supplier,
unless that leaded part was BGA.
For the "transition period", new part numbers were created for lead-free
parts for "Lead-free only" BOMs. All other part numbers allowed both
lead-free and leaded parts on the AVL, provided they are not BGA. This
is because non-BGA lead-free parts are backwards compatible. This means
that we have duplication of manufacturers part numbers under two
different internal part numbers.
Of course, some component manufactures changed their part numbers and
some did not. Therefore, both manufactures part number for leaded and
lead-free were allowed under the same internal part number on the AVL.
A few months after the conversion target date whereon we no longer
procured leaded parts, all leaded components that had not been consumed
were gathered and scrapped. On that point, we got lucky, only a few
thousand dollars worth of material remained. Our backup plan, was to
extend the transition period a little longer. (We had already extended
it twice.) The second backup plan was to create new part numbers for
the exceptions to the lead-free rule.
Once our inventory was all lead-free and all incoming material was
lead-free, we started cleaning the AVL of all leaded manufacturers part
numbers. Once that was cleaned up, we began cleaning up all BOM's that
referenced the "lead-free only" part numbers so that they referenced the
"old" part number that used to be leaded but is now lead-free. The BOM
clean up was the most painful since that impacts the pick and place
programs. For that reason, we started working this whole conversion
thing two years ago so that few BOM's were "lead-free only".
This left us with only a handful of lead-free BOMs, the rest were
"optional", and that option could be determined simple by changing the
solder paste. As more BOM's were converted to lead-free (by changing
the paste), some BOMs were left that had to remain leaded, due to the
leaded BGAs. The leaded BOMs have become the exception, and will fade
into obsolescence within a few years.
In short, we did not change part numbers except where we have exceptions
to the rule.
Ryan Grant
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Genny Gibbard
Sent: Monday, May 30, 2005 1:12 PM
To: [log in to unmask]
Subject: [LF] PN's changing
All right, I am in a big internal fight in my company. I thought we had
achieved consensus on changing PN's and had even come up with a format
to do
it. As soon as we started to try to implement it, however, two big
issues
came up.
1. The format we chose didn't work with the pick and place equipment (
we
have a small internal line for some of our SMT needs. The rest is sent
out)
2. When asking for input on alternative preferred formats, R&D
department
rose up and started to fight for no change at all.
The issues are:
a) Apparently the CAD layout database of parts has been stored by PN.
Which
means that they will need to copy and rename pretty much the whole
database.
(I won't say what I think of that 'brilliant' idea, or whoever thought
of
it...whatever happened to naming the database parts by their package
type???)
b) Our MRP parts database will have to increase by 50-75% in size,
making it
more unwieldy.
c) The MRP database entry could take up to 15 weeks of straight
keyboarding,
by those that currently maintain it - and that is just straight typing,
no
doing any of the other jobs they normally are responsible for...
d) The new PN standard will be stuck to the part forever, even once Pb
free
is the norm. We will still have to keep sticking our "F" on the end of
every new part we make forever and ever,...
One of the suggestions is that we keep the existing PN's for Pb free,
and
make new PN's for items that will stay "leaded". My argument is that it
is
totally backward from industry standard, and then we will have to
constantly
keep educating our suppliers in "our way" of doing things. The response
was
that they didn't think there was an industry standard FOR changing PN's,
because they could rattle off several co.'s that are not. Since caps
and
resistors make up a huge part of our database, and we can find examples
for
almost all of them that did not change PN's...
Anyone have any additional resources, papers, arguments to help fight
for
changing PN's?
I have been looking at the NEDA paper, and the iNEMI position.
Or should I just give up and allow whoever screams the loudest in the
co. to
win...?
Genny
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