Well the poke is getting bigger; the guy who has a pig in this poke is living high on the hog; a DTL golly is better than a whole Gee; we have spilled a lot of water, but still don't know the value of the crown: so rather than be Mr. Bundy, be like Grunde and take AABUS over to someone who does ENEPIG.
Grunde gets bonus points and my appreciation for using AABUS on TechNet.
Dewey
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Mike Fenner
Sent: Wednesday, August 15, 2012 6:15 AM
To: [log in to unmask]
Subject: Re: [TN] NTC Hard vs. Soft gold - mil std
So the gold has to be not too thick and not too thin, GOLDilocks in other
words.
Sorry for that, [and to those not familiar with the story of the 3 bears]
Regards
Mike
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Grunde Gjertsen
Sent: Wednesday, August 15, 2012 11:01 AM
To: [log in to unmask]
Subject: Re: [TN] Hard vs. Soft gold - mil std
Hi
The manufacturing/solder process is governed by J-STD-001, check out 4.5 in
the E revision. (E is reworked compared to D with respect to gold removal).
Only ENIG and ENEPIG (not so common on PCB's) can be used without presenting
"objective evidence" that embrittllement is not an issue.
I would be very suspicious soldering on any electrolytic gold plated
surface, if you do some math it takes doesn't take very thick gold on an SMD
pad to push the gold content to several percent. If I remember correctly
MIL-G-45204 specifies a maximum thickness of 100µ" Au which will give
seriously brittle solder and Au content maybe close to 10% on SMD pads.
IPC-6012 table 3-2 states max 0,45 gold on any surfaces to be soldered but
this is irrelevant prerequisite the J-STD-001 takes precedence.
One electrolytic Au solder finish you occasionally come across is "flash
gold" over Ni. This is also electrolytic but very thin. It can be used as an
etch resist but then the vertical surfaces of the pads is not covered. I'd
stay away from this bot for the reason I mentioned but also there is no
industry standard covering this process.
Electrolytic gold plating is specifically covered in ASSTM-B-488, I don't
have this standard but I suspect it is very general and I wouldn't bother
buying it at 40$ only for the reason you mention.
Rudys explanation in the previous post is my understanding too, hard gold is
alloyed with Ni or Cobalt is for (edge) connectors only, purity and hardness
is AABUS requirement.
Grunde
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Sefika Özkal
Sent: 15.august 2012 10:38
To: [log in to unmask]
Subject: Re: [TN] Hard vs. Soft gold - mil std
Hi everyone,
MIL-G-45204 is the military specification for electrodeposited gold plating.
I hope it helps.
Sefika Ozkal Piroglu
Aselsan - MGEO Division
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of R Sedlak
Sent: Tuesday, August 14, 2012 9:43 PM
To: [log in to unmask]
Subject: [TN] Hard vs. Soft gold
It is my understanding that both hard and soft gold are electroplated.
The difference is that "soft gold" is essentially pure, whereas "hard gold"
is highly alloyed, often with Cobalt, to harden it.
Rudy Sedlak
RD Chemical Company
--- On Tue, 8/14/12, Guy Ramsey <[log in to unmask]> wrote:
From: Guy Ramsey <[log in to unmask]>
Subject: Re: [TN] PCB finish: ENIG vs. hard gold
To: [log in to unmask]
Date: Tuesday, August 14, 2012, 11:32 AM
I am not sure I can talk to hard or soft gold, and suitability for
soldering.
But, I can say that it is possible to solder to electroplated gold, which is
different from Immersion Gold finish.
I think some people say hard gold when they mean electroplated gold.
There is a brief discussion of this in Coomb's Handbook.
Guy
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Glidden, Kevin
Sent: Tuesday, August 14, 2012 12:12 PM
To: [log in to unmask]
Subject: [TN] PCB finish: ENIG vs. hard gold
Hi everyone,
We have a PCB supplier who is offering "Hard Gold" as an alternate to ENIG
finish, due to PCB size and processing capabilities. The application is
Class 3 (mil/aero). The circuit is thin FR4 and subject to SMT reflow w/
Sn63Pb37 (non RoHS) solder alloy, and moderate flexing in end application.
Can anyone offer info on the differences between the two finishes, and/or
their suitability? Is there an IPC spec (or specs) that outline "hard
gold"?
Thanks,
Kevin Glidden
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