Harvey

As a pacemaker wearer, I have to rely on the testing of the
manufacturers, of which there are only a small handful in the world. My
first one was made by a Swedish company which, at the time, used
tin/lead (the X-ray of the implanted device clearly showed up the solder
joints as white blobs on the film). This company has now gone
solder-free, I understand, and uses silver-loaded epoxy for the
electrical connections. My present one was made in Switzerland but I
don't know how the connections are made. Although the devices are in a
titanium case, the connections to the electrodes come through a plastic
(polycarbonate???) moulding. I would not consider the working conditions
of a pacemaker ideal, extremely high humidity, low pH environment,
relatively high temperature (35 - 40°C). If there were ingress of
moisture through the moulding or due to lack of hermeticity in the joint
around the casing, I could well imagine that dendrites could be a
problem. That they can obtain a lifetime of 8 - 10 years under those
conditions is amazing (thank goodness!).

Brian

Harvey Miller wrote:
>
> Andrew and Doug
> How does one maintain the binary Sn 3.5Ag or Sn 0.7Cu at those precise
> eutectic compositions?  And I note that the pasty zones are very large when
> compositions deviate. What happens when the ternary SnAgCu alloy in SMT paste
> meets and joins the SnCu alloy used in wave soldering?
>
> How do you think the consumers of the world will like the reduced product
> lives.  And the product liability suits for failed ICs, turned into sieves
> by lead-free melting temps-- can't wait.
>
> Would you fly in an airplane whose black boxes are lead-free or use a
> pacemaker....
>
> So how much lead-free is being used today?  Is any one making money from
> lead-free?  How many lead-free-ready ovens have BTU or Vitrronics or Cookson
> sold?
>
> Lead-free is a bad, expensive joke, and not even Green.
>
> Harvey Miller
>
> ---------------------------------------------------------------------------------
> Leadfee Mail List provided as a free service by IPC using LISTSERV 1.8d
> To unsubscribe, send a message to [log in to unmask] with following text in
> the BODY (NOT the subject field): SIGNOFF Leadfree
> To temporarily stop delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL
> Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
> Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
> information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
> ---------------------------------------------------------------------------------

---------------------------------------------------------------------------------
Leadfee Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Leadfree
To temporarily stop delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------