Re: Gold plating the entire PCB
- From: MooseFET <kensmith@xxxxxxxxx>
- Date: Thu, 3 Apr 2008 17:41:06 -0700 (PDT)
On Apr 3, 10:52 am, qrk <SpamT...@xxxxxxxx> wrote:
On Thu, 3 Apr 2008 06:41:02 -0700 (PDT), MooseFET <kensm...@xxxxxxxxx>
wrote:
On Apr 2, 10:56 am, qrk <SpamT...@xxxxxxxx> wrote:
On Tue, 01 Apr 2008 21:40:10 +0000, Guy Macon
<http://www.guymacon.com/> wrote:
qrk wrote:
It's the thickness of the gold layer. Supposedly, immersion gold layer
is thin enough (<1um) where its absorbed into the solder and not
enough to cause embrittlement.
...but only if the entire gold surface is wetted by solder.
This is not the case if you gold plating the entire PCB.
You're only worried about the part that gets soldered. Most boards,
these days use a soldermask to prevent solder from getting sucked off
the pad down the trace. If this is for a home made board without a
soldermask, then disregard everything I've said. What I'm spewing is
for commercially made boards.
Also, after the gold is dissolved, the solder has to wet
tin, not copper.
After the gold is dissolved, the solder is in contact with nickle
plated over the copper. Commercially plated boards have the copper
pads as the base material, nickle plating over the copper, then gold
plating over the nickle.
Oh-oh. I can't have that nickel in there. Does the same apply for
the solder getting down to the copper?
I don't know if immersion gold is possible over copper (no nickel).
You need to talk to your board supplier. As someone else mentioned,
they stripped the gold off their solder terminals.
IIRC, that wasn't anybody who mattered :>
That seems like a
lot of work for pcb pads.
I don't think I need to do anything like that. I will have to check
the gold over copper issue and whether conductive epoxy sticks to gold
well enough. Once of the other engineers brought that issue up today.
I may also skip the solder mask on one of the PCBs since it is working
more as a mechanical part than as an electrical part. Someone did
comment about the solder running along the trace. But I suspect that
it isn't going to be an issue because I have huge trace to trace
clearances on that part. The one worry I do have is about the
boundary where the solder stops.
.
- References:
- Re: Gold plating the entire PCB
- From: MooseFET
- Re: Gold plating the entire PCB
- From: qrk
- Re: Gold plating the entire PCB
- From: Guy Macon
- Re: Gold plating the entire PCB
- From: qrk
- Re: Gold plating the entire PCB
- From: MooseFET
- Re: Gold plating the entire PCB
- From: qrk
- Re: Gold plating the entire PCB
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