Gary,
In a nutshell, here are some answers:
1. Depending on the industry (commercial vs. civil vs. aerospace), some
manufacturers have made the conversion to Pb-Free. I know that Nortel
converted some of their cell phone line in Europe to Pb-Free. I've heard
that HP is in process of converting some of their commercial lines to
Pb-Free.
2. Depending on your manufacturing equipment, you may have problems reaching
the Pb-Free reflow soldering temperatures. For example, for SnPb, reflow
soldering is usually 220C. For SnAgCu, reflow soldering temperatures are
approximately 240C, with some alloys (depending upon the vendor) getting as
high as 260C.
3. At such high temperatures, board materials and components may not
survive. I've run FR4 through at the higher temperatures successfully.
Boards (especially polyimide boards which absorb moisture like a sponge)
must be baked out thoroughly to assure no moisture is entrapped. Concerning
components, plastic components must be baked out very thoroughly to prevent
popcorning.
4. With proper care, you can meet Class 3 soldering requirements with OSP,
but if I had a preference, I would go with immersion Sn or ENIG. I know
folks are working on Pb-Free HASL, and I would be interested in what the
forum has to say on that one.
From a product reliability perspective, depending upon how much care you put
into the process, you can achieve similar reliability results to SnPb.
Suggest that you get a copy of the Pb-Free Component Focus Group's report
from IPC Works 2001 as 1 of many sources of information on reliability. The
NCMS report is another source of information.
Good Luck.
Lee Whiteman
Senior Manufacturing Engineer
E-Mail: [log in to unmask] <mailto:[log in to unmask]>
Ph: (610) 362-1200 x208
Fax: (610) 362-1290
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]]On Behalf Of Gary Bremer
> Sent: Thursday, January 10, 2002 3:44 PM
> To: [log in to unmask]
> Subject: [TN] Lead Free Soldering
>
>
> I am looking at moving my soldering process to use leadfree solder
> sometime this year. Has anyone already shifted over to using
> leadfree solder? What type of problems would I expect to
> encounter with using a leadfree solder? The solder material that
> NEMI is suggesting is SnAgCu, is this going to pose any real
> problems because the temperature is at 217° Celsius with the
> laminate material or what components are selected? Will I be
> forced to change the finish on the bare board from HASL? Any help
> or suggestions I get will be greatly appriciated.
>
> Gary Bremer,
> Manufacturing Engineer
>
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