don't get me started ...
the guy who did the homogeneous thing should look for another line of
work IMHO (am trying to be dimplomatic here)
this is all very productive too (that is sarcasm)
as we are changing hundreds of part numbers to the lead free numbers
availability is being hurt too
BACK ON TOPIC
what is the definitive word on the minimum via in pad hole size that one
can paste up reliably ?
anybody know or have good data ?
.
.
.
.
going OT here and below
BUT WORST OF ALL (true story follows)
we have a valued supplier of switches in taiwan and have used their
parts for 4-5 years with zero trouble, 10k-20k pcs
a while back they started breaking
for a time it seemed like a blip
then it got worse
then they assured me the problem was solved
then it got worse again (this is starting to cost some real money at
this point)
much later i learned that all this trouble was because they had to
retune their line and materials to make parts RoHS temperature resistant
because of the higher soldering temperatures used for lead free and had
to changes recipes of the internal plastics
there was no service data on their new formulas, just ginuea pig customers
i predict more and more of this sort of indirect trouble as all these
parts get in the pipeline
PS
quiz
a car battery contains 18 lbs of lead
how many BGA's does that equal ?
(i have no idea of the correct answer)
ds
_______________________________________________________________________
Integrated Controls, Inc. Tel: 415-647-0480 EXT 107
2851 21st Street Fax: 415-647-3003
San Francisco, CA 94110 www.integratedcontrolsinc.com
Jon Elson wrote:
Brad Velander wrote:
Jon,
I believe that the key to the 0.1% limitation is the fact that it
must be a homogeneous part. i.e. one part that cannot be reduced to
lesser sub-materials. A solderball on a BGA is not a homogeneous part.
Basically I believe that no electrical component is a homogeneous
part. I believe that a straight steel screw containing 0.1% lead
content is a homogeneous part, a screw plated with something that
contains 0.1% lead is not a homogeneous part because the plating can
be removed and therefore is not homogeneous. Same would stand for a
BGA. Unless there is something which has come along recently to change
this since I last was looking at the issue(s).
At least this is what I have come to understand about the 0.1%
limitation. Otherwise there would be a lot of assemblies that could
pass the 0.1% lead rule with no special lead-free concerns because the
lead would not make up 0.1% of the total weight. The key word of
concern is the word "homogeneous".
OK, so I think you are agreeing with me that the BGA parts with
Pb-containing
solder balls would not be RoHS compliant. Do I have that right?
The way you describe it, then, the entire BGA component must have
absolutely
ZERO lead in it to be compliant. Only if the part is entirely homogeneous
can there be any lead at all in it.
I'm still totally astounded that we are fretting over milligrams of lead in
electronic devices while car batteries have tens of KILOGRAMS of lead in
them. My guess is that the amount of lead scattered about in car accidents
is WAY more than the lead leaching out of some circuit boards.
Jon
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