OmniUSB - further boards to make

Eric Smith spacewar at
Fri Sep 4 03:37:29 CDT 2015

Thanks, Sean. I'll have to inquire as to whether they offer hard gold
over nickel for edge connectors. I know of a bunch of relatively
low-cost PCB fabs, but they generally either don't offer hard gold, or
only on large runs, or only for really big bucks.  The actual cost of
the gold on a hard gold edge connector is only a few dollars, which
doesn't justify adding >$50/board on a short run, IMO, but that's what
I've usually been quoted.

Note that "hard gold" is much different from electroless nickel
immersion gold (ENIG), which is a much more commonly available surface
finish that is used on an entire board surface, but NOT suitable for
edge connectors. ENIG uses a very thin gold layer (about 0.1μm gold
over 2μm nickel) that will wear off the the edge connectors in only a
few insertions. Hard gold for edge connectors is typically 1-2 μm of
gold over 3-6 μm of nickel.

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