Dear all,

II have just loaded from www.lead-free.org the new DTI Report UPDATE 2000
“Analysis of the current status of lead-free soldering - one year on”.

The section on “Component Terminators” irritates me enough to write this
message.

The report claims that “In general, component companies have been fairly
slow to react to the impending change to lead-free soldering, possibly due
to a low level of customer demand”.

Alternatives to Sn/Pb are given they are as follows:

Pd/Ni
The DTI now admit that this finish does not provide the solderability
expected from conventional soldering technologies unless the soldering
temperature was in excess of 250 deg C.
Ignoring the problems that may be caused by this elevated temperature there
is still the simple fact that palladium is currently twice the price of
gold!

Sn/Bi, Sn/Ag & Sn/Cu
For these alternatives the DTI state “Each has advantages and disadvantages
in processing and performance and a ‘favourite’ system has yet to be
established”. The main disadvantage from the point of electroplating any one
of these finishes is that they do not currently exist as a commercial
process!

Sn
This is the only viable alternative to Sn/Pb that currently is available and
does not involve excessive sums of money. The DTI report states “Concerns
over tin whiskering are being addressed by NPL, ITRI and others, though work
has yet to be fully completed”. Kay Nimo of ITRI in November 1999 requested
information on tin whiskers from this forum. I spoke to Kay in February and
was informed that my reply was the only one received!


Conclusion
The component companies cannot be held liable for the fact there are no
acceptable alternatives to Sn/Pb. The industry as a whole has to decide if
pure Sn is acceptable (i.e. whiskers are not a problem) or will have to pay
the increased cost for precious metals.

My personnel opinion is that we are all wasting our time and I believe this
is highlighted by the reduction of mail on this subject.


Sorry about the length of this message, I look forward to receiving
comments.

Best regards,
David Gowlett
Technical Director
Palmer Plating Ltd
Cirencester
England


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