Hello,

Although IPC-6012 specifies a minimum thickness of 0.8 micrometers (30
micro inches) of gold for Class 1 and 2 edge-board connectors, it seems
that more and more suppliers are suggesting thinner and thinner gold
plating as a low cost alternative.

Looking back into this forum's archives, I found the 1995 tread 'Where
did 30m" for gold Tab plating come from?'  with very good information
but no definite answer.  One poster performed an experiment about
thickness and connection cycles (see attached message fragment), and
found out that a 20m" finger gave up at about 10 cycles.  If these
results are still valid (I don't see why not), how come PCB vendors are
even suggesting flash gold (2 to 7 micro inches) as an acceptable
option?

I also posed this question (via E-mail) to two connector manufacturers,
AMP and Burndy.  AMP answered immediately but did not provide a definite
thickness (I got their connector's specs and insertion rates thought).
I have not received a reply from Burndy yet.

Do anyone has more information or pointers about this issue?  Has
technology advanced so much that thin flash gold is acceptable for
edge-board connectors in a Class 1 product?

Thanks,


Carlos R. Robert
Hewlett-Packard Puerto Rico

| _____________________________________________________
|
|
| Date: Wed, 27 Sep 1995 17:18:37 EDT
| From: [log in to unmask] (MR NORMAN S EINARSON)
| Subject: Re[2]: Where did 30m" for Tab plating co
|
| To all that have inquired about 30 m gold thickness:
|
| This question would be better answered with a required application.  Let
| me try to cover most of this subject and apply various applications.
|
| Many years ago (too many to mention), I performed an experiment to find
| out how many insertions I could get from a gold plated board into a
| connector.  Carefully selecting the same thickness boards (.  062") I
| found the approximate following results, always with 100 M base nickel.
| 100m gold = 500 insertions; 50 m gold = 300 insertions; 30 m gold 50 to
| 75 insertions; 20 m gold 10 insertions.  As you can see, the insertion
| count reduces rapidly as the gold thickness reduces.

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