My recommendation is to approach this in stages - first, all components that will be used on LF assemblies must be RoHS compliant, and it is my opinion that these can be used in existing lead based processes, although some process parameters must be modified to ensure proper wetting. Verify that either your existing components are compliant, or are not and a compliant component is available (in which case you must determine how much of your existing stock will be used up by the cutover date and how much may need to be disposed of in another manner), and which components are not available in a compliant version in which case the product designers need to be involved. Do the same exercise with bare boards.

Once you have all compliant components and boards, set a date to cutover to LF solder (yes, go home Friday running tin/lead, come in Monday and start running LF. 

I don't think you need to change part numbers of components, but it will be a major chore keeping track of your current inventory, and a FIFO system must be followed with no exceptions. 

But I tend to oversimplify things.

Blair Hogg
QA Manager
GAI-Tronics Corporation

>>> [log in to unmask] 02/08/05 10:40AM >>>
Your point is good.  However, our system is such that t
Camille,

Your point is good.  However, our system is such that to change the
underlying parts on a BOM requires an ECO (Engineering Change Order) and
data entry, not to mention new parts to buy and double the bins in the
stockroom.  There has to be some form of traceability to know the
history of your changes.

There is no easy way out of this mess.  We have to face the fact that
this is going to be an enormous task and we will make implementation
mistakes.  We are humans and we are prone to making mistakes... not that
I would <grin>.

Wouldn't it be nice if we could go home on Friday night running tin/lead
and start Monday morning lead-free.

Just my opinion.

Phil

-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of Camille Good
Sent: Monday, February 07, 2005 5:09 PM
To: [log in to unmask] 
Subject: [LF] Putting new part numbers on RoHS components - was Re: [LF]
marking PWAs as lead-free

From my limited knowledge:

Against adding new part numbers - A LOT of extra
paperwork and hassle as you go through all your old
part numbers.

For adding new part numbers - It becomes a LOT easier
to make sure an assembly is RoHS-compliant.  Just look
at the BOM and make sure that none of the old-style
part numbers are on the supposedly RoHS-compliant BOM.



     My experience with people is that simpler systems
lead to less opportunities for mistakes,
misunderstandings or forgotten steps.  But making a
system simple (in this instance) for manufacturing
means a LOT more work on the data-entry side.
     So, it is really a philosophical decision.  Which
are you most worried about occurring, a mistake which
will put a non-RoHS compliant part on a supposedly
RoHS-compliant assembly, or extra costs, personnel
time, overhead, opportunity costs, etc. from the
duplicate parts numbers being put in the system?
     If you know that your system is rock-solid,
mistakes on BOMs are rare if ever, your personnel are
all well-trained about which parts to take from which
bins and it is generally unlikely that a non-RoHS
compliant part will be put in a
should-be-RoHS-compliant assembly and you are in a
low-margin or very competitive segment of the market
where extra data-entry and -tracking personnel are not
really affordable, then you might get by with only
having new part numbers for non-backwards-compatible
parts.
     But if you know you are going to have both leaded
and lead-free assemblies being built in the same
factory for quite some time and you have any worries
about human error causing non-RoHS-compliant parts (or
worse, leaded solder!) to be used in a
supposedly-RoHS-compliant product or assembly line,
then a whole different set of part numbers for ALL
RoHS-compliant components is probably the way to go.
That way, personnel training is simpler - assemblers
know if it's used on the RoHS line then it had better
come from a bin of parts with the new part numbers,
receiving and purchasing know that any component that
goes in bins with the new part numbers had better be
RoHS-compliant, and if there is a question about a
particular assembly being RoHS-compliant it is easy to
scan through the BOM and make sure all the components
have the new part numbers.

-Camille
Portland, Oregon

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