Bob
I'm pretty sure tellin' you no news ; just in case :
The Euro establishment should give everybody clear indication the 'good ol'
motherland will protect it's own market by any well sounding bull possible ;
and a good eng. can make a feasibility study black or white as well as a
good lawyer :
The glittering politically correct top of fiscal iceberg heading the Apple
way does have much more sinister base .
Any headstart will do nowadays ; this no lead pet is useful indeed .
Talkin' about land leaks ; I just popped to local hardwarehouse to be
horrified that apart from the more correct alluminium strips they sell tones
of 1/16" thick leads rising damp insulating brick strips a foot wide = that
beats any fabricators heads over heels !
Disagree with the gold reliability statement ; just completed telecom
category of IPC-SM-785 (Werner's own) just about without a crack to such a
degree I'll do it again just to verify the too good to believe results .
And just because the 001-B states whatever > just as you said > it's dated ;
and not specific at all > just check the millions of mobiles .Which one of
them does have the gold removed ? I'd say that statement is not addressed to
flash gold ; of all the different plating specs .
On the same NiAu finish where we solder on 0.3 - 0.5um Au we tested carbon
pill switching on silicon buttons to 1M cycles without resistivity changes .
Tried most finishes ; from versatility point of view you can't beat the gold
; the lead drop is incidental .
Yes ; no clean keeps you awake .
On fabricators side, they should pay assemblers ; as hasl is a nasty, hot
process .
So far they managed to hood us to parity .
See yo'
Paul Klasek
http://www.resmed.com
> ----------
> From: Circuit Connect[SMTP:[log in to unmask]]
> Sent: Friday, 29 January 1999 4:31
> To: [log in to unmask]
> Subject: Re: [TN] Removal of Lead
>
> -----Original Message-----
> From: David Whalley <[log in to unmask]>
> To: [log in to unmask] <[log in to unmask]>
> Date: Friday, January 29, 1999 10:59 AM
> Subject: Re: [TN] Removal of Lead
>
> Whalley: The draft European WEEE legislation proposes prevention of
> electronic equipment being consigned to landfill.
> Lazzara: Presumably due to lead being a toxic substance.
>
> Whalley: An additional ban on the use of lead solder therefore cannot be
> justified for this reason. There are also existing technologies for the
> recovery of the lead from the solder in obsolete electronic hardware.
> Lazzara: Wait - Is this the logic where a pound of cure is better than
> an
> ounce of prevention?
>
> Whalley: All of the proposed replacements are significantly more expensive
> than tin/lead.
> Lazzara: According to a January 1997 report by the ITRI*, "Lead-Free
> Solderable Coatings and Their Compatibility with Lead-Free Solders"
> (Kelly,
> Ahluwahlia, Nimmo), the difference in cost between OSP, palladium, silver,
> gold and tin alternatives were not significant. But that was 2-years ago.
> Since that early 1997 report many North American shops offer soft gold
> (in-volume) at no additional charge. Ditto OSP. And several companies now
> offer non porous immersion tin below the cost of tin/lead HASL.
>
> Whalley: Most also require a higher reflow temperature and hence greater
> energy costs.
> Lazzara: Not in all cases. I believe immersion tin tends to dissolve into
> solution at lower temperatures than is necessary to render HASL coatings
> liquid. But any slight elevation in temperature that might be required is
> offset by the substantial thermal stress removed from the PCB by
> eliminating
> HASL. Ironically, it is precisely the energy savings from eliminating HASL
> that permits the alternative finishes to meet or go below the cost of
> HASL.
>
> Whalley: There are also issues regarding the reliability of the
> alternative
> alloys. As far as I am aware no cost/benefit analysis has been undertaken
> to
> justify a ban.
> Lazzara: Reliability has and continues to be a concern with Ni/Au
> embrittlement, to such an extent that the ANSI-J-STD-001-B actually
> prescribes the removal of all gold - from components and solderable
> ands - prior to assembly. But the newer alternatives have done very well
> in reliability testing and the reputations of their 1960's predecessors is
> fading (e.g., "...growth rate of tin-copper intermetallic compounds on tin
> coated copper is similar to that of Sn-40Pb coated copper, not greater as
> is
> sometimes feared."*) Please do pursue a copy of the mentioned ITRI report;
> I
> think you'll find it addresses the reliability issue objectively, and much
> more data from many sources has since been generated concerning the
> reliability of these coatings.
>
> Whalley: ...but as usual the European Commission does not regard factual
> evidence necessary before it drafts legislation.
> Lazzara: I suspect the EC isn't unique in that mode. Yet many companies
> are
> just the: They'll regard the factual evidence but effect NO change -
> which
> in-part explains why we have such institutions as our Environmental
> Protection Agency (EPA).
>
> And THAT brings us back to our beginning!
>
> Bob Lazzara
> Circuit Connect Tech Support
> Georgia Service Bureau
>
> TEL: 800.560.9457 FAX: 888.453.0520 BBS: 603.889.5385
> alternate eMail: [log in to unmask]
>
> *In the U.K., the ITRI is the International Tin Research Institute. They
> can
> be reached electronically at:
> http://www.aslib.co.uk/aip/subs/itri.html
>
> ################################################################
> TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
> ################################################################
> To subscribe/unsubscribe, send a message to [log in to unmask] with
> following text in the body:
> To subscribe: SUBSCRIBE TechNet <your full name>
> To unsubscribe: SIGNOFF TechNet
> ################################################################
> Please visit IPC's web site (http://www.ipc.org) "On-Line Services"
> section for additional information.
> For technical support contact Hugo Scaramuzza at [log in to unmask] or
> 847-509-9700 ext.312
> ################################################################
>
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################
|
