I don't think you are right. The tinning is done after the packet is
moulded, in my experience. It would be very hazardous to mould a
thermosetting polymer over a tin-lead alloy, which can easily creep,
destroying the hermeticity.
Brian
to Paul Taylor wrote:
> Doug
>
> Stripping and re-tinning the leads does the outside of the IC, but unless
> you aim to split the IC's down the middle!! then there will be lead
> trapped in the leadframe under the epoxy. This would constitute a fail in
> RoHS.
> I suggest you either put pressure on you IC manufacturer to supply in a
> RoHS compliant leadframe or re-design. Better get your skates on, there
> is not much time left.....(re-design, re-qualify etc)
> Also I agree with Doug Rohm, it would have to survive the higher
> temperatures
> Better get that CAD package out....
>
> regards
> Paul
>
>
> Paul R Taylor
> Senior Engineer, RoHS Compliancy Group, IED
> Pitney Bowes Ltd
> The Pinnacles, Elizabeth Way, Harlow, Essex, CM19 5BD
> tel: +44 1279 449 744 fax +44 1279 449 594
> email: [log in to unmask] website: www.pb.com
>
>
>
> "Douglas, Scott" <[log in to unmask]>
> Sent by: Leadfree <[log in to unmask]>
> 27/10/2005 20:38
> Please respond to
> "(Leadfree Electronics Assembly Forum)" <[log in to unmask]>; Please respond
> to
> "Douglas, Scott" <[log in to unmask]>
>
>
> To
> [log in to unmask]
> cc
>
> Subject
> [LF] Making IC's RoHS Compliant
>
>
>
>
>
>
> Dear Group,
>
> We are looking for a way to avoid re-designing a number of PWB to replace
> non-RoHS compliant IC's with other compliant (not drop-in replacement)
> parts. In a discussion today with our component engineer, we wondered if
> we could take our stock of non-RoHS compliant IC's, send them to some lab
> someplace, have them (dip, acid etch, whatever) remove the tin/lead solder
> plating the leads and then have the leads re-plated with lead-free solder.
> This assumes a plastic or ceramic package with standard metal leads, maybe
> through hole, maybe surface mount. Could we do this and then claim to be
> RoHS compliant? Anything else we should think about in this?
>
> Scott Douglas, NCE
> Compliance Engineer
> Harman Specialty Group
> 3 Oak Park Drive
> Bedford, MA 01730
> Phone: (781) 280-0406
> Email: [log in to unmask]
> Web: www.harmanspecialtygroup.com
>
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