Dear Ken,

We have seen that mixing lead-free solder with tin-lead components can
result in areas of the solder joint  with the Sn62/Pb36/Ag2 (179 m.p.)
alloy surrounding grains of the lead-free alloy, resulting in poorer
fatigue resistance and possible field failures.  This is dependent on
several factors, including the reflow profile used and the operating
conditions of the assembly.
 
Regards,
 
David Suraski
AIM
+1-401-463-5605 ext. 5210
www.aimsolder.com


-----Original Message-----
From: Ken Patel [mailto:[log in to unmask]] 
Sent: Tuesday, June 01, 2004 7:05 PM
To: [log in to unmask]
Subject: [TN] Impact of Mixed, Lead and Lead-free, components on
assembly proce sses


Dear Technetters,

I have been informed by my engineering that many part manufacturers
started providing list of EOL components (end of life) as they are
switching to lead-free parts.



As there will be a transition period from current PbSn process to
lead-free process, I see the following phases.

(a)    Lead components processed using eutectic solder (your current
process).

(b)    Mixed components (lead and lead-free) running using eutectic
soldering process

(c)    Mixed components (lead and lead-free) running using LEAD-FREE
assembly process at CM.

(d)    Lead-free components running on LEAD-FREE assembly processes.



Based on above, I have the following primary concerns.

(1)    Do you see any problem in processing mixed, lead and lead-free,
components on a board?

(2)    Will there be change in thermal profile when running lead-free
components on PbSn process?

(3)    If higher temperature is required then what is going to happen to
lead processes component? They may not withstand the high temp.

(4)    Should we ask for certificate from the lead component suppliers
stating their lead parts can with stand higher temp?

(5)    Are you preparing we imagine for lead-free processes in near
future
and when?



Any help will be highly appreciated.



Re,

Ken Patel


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