On Tue, 2 Jun 2015 01:58:55 -0700 (PDT), snipped-for-privacy@gmail.com Gave us:
Gee... junior willackers.
ONE MICRON of gold is NOT going to cause intermetallics or embrittlement.. Dig?
A gold plated mil cup which is not properly evacuated first WILL cause it in the wire that gets soldered into it. That is why there is an evacuation procedure. That is also why the military gets an RoHS exemption. GET A CLUE.
Nope, you couldn't even solder to a bare board with a soldering iron. I think there must have been some kind of contamination on the surface, a very thin residual layer of solder resist possibly.
It's just funny. The parts fell off when I tapped the side of the board.
Re gold; it is easier for assemblers to work with and probably better quality overall but I do not believe it is the most common finish overall, due to the added cost. Sure you will see it for lower quantity production and a lot of high-end stuff.
-- John Devereux
Isn't that the tax on your ohms?
But you're AlwaysWrong. This is no exception.
Again, it's not necessary if the line is set up properly.
On Tue, 02 Jun 2015 13:28:39 +0100, John Devereux Gave us:
Which obviously means that no paste was screened onto the board to begin with. DOH!
Even the parts that had paste and minuscule fillets would not pass as sufficient. Yer process controls and QA inspectors are fuxed up.
The paste needs to be kneaded for a half hour before it even leaves the jar, minimum. Then, it has to be fresh. Then, the stencil has to be thick enough ton actually apply it to the PCB, and the windows need to be large enough to actually get enough on the pads to perform a basic soldering operation. Then, it needs to go into the reflow oven without sitting somewhere for hours on end first.
You may also want to attach certain parts with SMD adhesive as it appears the placer programmer cannot even sit a chip down where it belongs... You know... PROPERLY registered. I saw quite a few problems and would blame none on the gold plating.
That is, of course, considering that is what ended up on the board. I would question the PCB fab house as well. Especially since you claim that you could not even "wet" the board with a hot, hand held iron.
I would also question your choice of flux, and even consider a de-oxidation session on the boards before they get pasted.
On Tue, 02 Jun 2015 08:59:03 -0400, krw Gave us:
In Israel, the income tax is 105%.
On Tue, 02 Jun 2015 09:01:43 -0400, krw Gave us:
Motherboards are gold from top of the line makers. You claim otherwise? You're an idiot.
On Tue, 02 Jun 2015 09:02:42 -0400, krw Gave us:
You are beyond stupid.
Of course it was. You could see the balled up solder on the parts.. Plus everyone else is not as stupid as you assume.
Nope.
maybe but it was nothing to do with that.
yes quite, that is the givaway that it is nothing at all to do with anything other than the bare boards as received. It was the same for unprocessed boards by the way.
The bare board supplier admitted a problem on their side, the person responsible was "looking for other opportunities", to use their charming euphemism.
-- John Devereux
My production people want it, so they get it. PCB cost averages about
1% of the price of our products, so the gold flash must be ballpark 0.1%.Besides, the gold looks cool.
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
On Tue, 02 Jun 2015 15:00:31 +0100, John Devereux Gave us:
There is a definite time limit between pulling the paste and reflowing an assembly. Breach that RULE, and you are asking for failure modes, then you stand around looking for others to blame. Nice try.
On Tue, 02 Jun 2015 15:00:31 +0100, John Devereux Gave us:
Their fine print says "It *looks* like gold, but it is really brass, and a bad alloy of that even. :-)
Gotta read that fine print. BAD fab house!
I'd sue, big time.
Yes I know, they know, they didn't.
It amazes me, the absolute certainty with which you are able to pontificate from the other side of the world, about something that happened 15 years ago, where you know nothing of the particulars or the people involved. Even when you are told the actual, easily proven reason, no, it was something else, entirely from your imagination.
-- John Devereux
There's barely any solder on most of those pads.
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Did the parts separate from the solder, or did the solder separate from the board?
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
The solder would not wet the board. The solder was there it was just repelled from the pads and ended up entirely on the "pins". it was due to a thin layer of solder resist or some such over everything (as detailed in another post).
You could try to tin the pads manually with an iron, nothing unless you scratched away the invisible layer.
-- John Devereux
Don't blame gold; it's just an element. Blame the board house.
Every PCB house seems to screw up sooner or later. Some screw up most of the time.
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
-- John Larkin Highland Technology, Inc picosecond timing laser drivers and controllers jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Was this the so-called "black pad" issue?
(caused by corrosion of the Ni barrier layer during the Au plating)
I've not (knock on wood) seen that yet.
-- Best regards, Spehro Pefhany Amazon link for AoE 3rd Edition: http://tinyurl.com/ntrpwu8 Microchip link for 2015 Masters in Phoenix: http://tinyurl.com/l7g2k48
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