Gen:
I agee with Ioan. XRF mesurements of in situ solders are not easy and not
very accurate, considering that in your case any Pb would probably not be
uniformly distributed. However, knowing what the European enforcement
bodies are likely to do, if you have the solder tested via XRF and the Pb
concentration is low - not just below 0.1%, but anywhere near 0.1% - they
are unlikely to challenge your claim that the product is compliant. If they
saw 40% lead with an XRF, they would likely proceed to quantitative analysis
by ICP-AES to confirm the high lead reading. Some enforcement authorities
might be more agressive and go straight to quantitative analysis, but they
will have to be quite sure of themselves if they want to prosecute someone
for Pb values a little higher than 0.1%, particularly if you did your due
diligence and had your reflowed solder checked and can document that with a
test certificate. The only problem with having an instrument manufacturer do
the test is that they likely do not qualify as an independent test lab and
cannot give a certificate that would hold the same weight as one from a
laboratory.
Tim McGrady
----- Original Message -----
From: "Tempea, Ioan" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Saturday, October 28, 2006 6:38 PM
Subject: Re: [LF] Leadfree assembly contaminated?
Gen,
how could you do that? I bet nobody else did it, including ourselves.
As per our experience and XRF measurements you should be OK if the wicking
of the pads is very very good. For a very well wicked pad, no spikes or
little islands, just a flat pad left after the cleaning, we measured about 3
to 4% Pb in the coating layer. Imagine adding a comparatively huge volume of
lead-free solder on top of it, you end up with the Pb diluted well below the
0.1% treshold.
Of course, you don't kow how well your CM did the cleaning, but if you ask
them to change the IC again, the Pb will surely go away. Now, how confident
are you in your PCB quality to do that, only you can answer.
We have an XRF and I tell you from my painful experience that measuring in
electronics using this technology is not a piece of cake. Therefore, if you
want to qualify the boards, I suggest you contacted XRF machines
manufacturers, tell them you are interested in buying one and have them
check the boards for you, for a test. Not too orthodox, but life is not
always fair, is it?
Good luck,
Ioan
-----Original Message-----
From: Leadfree
To: [log in to unmask]
Sent: 27/10/2006 4:20 PM
Subject: [LF] Leadfree assembly contaminated?
Our CM placed and reflowed an IC with SnPb leads on a leadfree assembly.
Then they removed it and replaced it with the leadfree part.
Is this assembly contaminated with Pb to a level that would be a
failure under RoHS? We have several boards in limbo.
Does anyone know of a lab capable of determining this, in Canada?
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