Steve,
You need to be aware of mixing "lead free" components with the leaded
solder process.
This is most notable when dealing with BGAs and other components (COTS)
that have
solder balls and/or bumps that are "lead free". The reliability data is
rather scarce (to many variables!!).
David A. Douthit
Manager
LoCan LLC
Steve Gregory wrote:
>Hi Ryan!
>
>Unfortunately, this isn't going to be a transitional thing for me, at least in the near future anyway. We're a contract assembly company that builds things for most of the the major DoD contractors, and most of them have told me informally that they aren't even thinking about lead-free. Some have actually put it into writing. I've pasted a few paragraphs as an example that was sent to us recently below (I've blanked out the company name:
>
>
>"At present, (Blank) will continue to order and assemble electronic products using tin-lead solder. There are currently no (Blank)customer contracts requiring transition to lead-free solders.
>
>There are, however, (Blank) customer contract requirements for (Blank) to continue using lead-based solders. These requirements are currently driven by a lack of community acceptance of reliability and design data to safely transition to lead-free solders.
>
>We are also concerned about our ability to guarantee the life of products, and our lack of process controls within (Blank)to manufacture with lead-free components.
>
>If there is a change in position, (Blank) will notify our suppliers of any new requirements. Presently, (Blank) is requesting that all suppliers provide lead-based electrical components and assemblies to (Blank) on all orders.
>
>(Blank)is monitoring industry work/study group efforts involved in lead-free solder transition, and while much still needs to be done, we are also establishing an internal program to evaluate transitioning to lead-free electronic assemblies, if and when that time comes."
>
>
>So, I have that stance from existing customers, and have just learned that we are pursuing business with a company that will have their products marketed in the EU, and must comply with WEEE and RoHS. So I find myself in quite a "pickle", as it were...
>
>I envision that we will be building tin/lead products for quite a few years yet. Military minds don't change easily. Besides, there are exemptions for defense related electronics.
>
>But if we're going to be build lead-free stuff along with tin/lead stuff, I'm inclined to agree with Mike Fenner and set-up completely separate areas with an impenetrable wall between them ;^)
>
>-Steve Gregory-
>
>
>
>Hi Steve,
>
>We're doing it no sweat! :) O.K., just kidding. Actually, it hasn't been too bad, we require our solder paste suppliers to visually mark their tubes with a "green" color so they aren't easily mixed.
>
>(Snip...)
>
>That would be easier to replace the eventually contaminated pot and keep pure. Ideally, you would convert all wave solder machines to lead-free, assuming all your leaded customers agree to the change. Then the only risk is production operators using the wrong solder paste.
>
>Good luck on the conversion.
>
>Ryan Grant
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve Gregory
>Sent: Saturday, December 04, 2004 6:21 PM
>To: [log in to unmask]
>Subject: [TN] Lead-free, and not lead-free...
>
>
>Hi All!
>
>I've got a problem that I've been worrying about all weekend. It may come to pass that we will be building both lead-free, and standard 63/37 stuff...whoa is me.
>
>I'm interested in stories from those that have done that...what the hell did you do?
>
>Is this something that can be done? It probably can, but me, being the pessimistic sort, thinks that you're just asking for trouble when you try to mix the two...
>
>-Steve Gregory
>
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