Moonman
The input for most PCB houses is the ubiquitous Gerber file, frequently
CAMmed. There are inexpensive viewer/editor for that, such as at
www.lavenir.com. Your problem is sticking with a propietary make, rather
than an industry standard.
Regarding gold: electroless is an easier and cheaper operation for thin
thicknesses. My experience though is rather negative (organic and
inorganic co-deposits, equal porosity). I prefer electrolytic but, as
you rightly point out, in thicker deposits, which has the disadvantage
of embrittling solder, if overdone. If wave soldering, I'd go for as
much as 1-2 um but for reflow, this may be too much by a factor of two.
However, the nickel underlay will passivate less, if the gold bath is
chosen carefully for minimum porosity and co-deposits, providing more
reliable soldering.
It's not a personal problem but one of the best compromise for all the
parties concerned (cf. CE)
Best regards
Brian
Earl Moon wrote:
>
> Folks,
>
> I've never found an adequate/inexpensive CAM viewer/editor for .brd, from
> Allegro, files. I know Valor does it and I know many others have asked the
> same question but to no avail. Does anyone have a CAM package capable of
> viewing and running DRC's on Cadence design stuff without having to pay
> through the nose, or other orifices, and without having to rely on ODB ++
> output as in CAM350's case.
>
> Also, never done electrolytic gold over nickel for SMT. Assuming it is
> similar, concerning solderability minus black stuff problems, to immersion
> gold in that it gets the job done good or bad. Can't understand why my
> current supplier goes outside for immersion and has the same thickness
> electrolytic gold capabilities in house.
>
> First, has anyone stories to tell about electrolytic gold and its properties
> pertaining to solderability? Do I have to worry about black pad? Why is 2
> millionth's gold over about 200 millionth's nickel now the preferred
> standard? Used to be 4 over 120, or so, was the nominal. Man/woman, that's
> seems a lot of nickel with extremely littl gold over it.
>
> Looked back at some postings, too many to count, and found Dave Hillman's
> January posting to be most useful concerning thickness versus absorbtion
> and rates, etc. Same holds true for electrolytic, I'm sure as we're talking
> thickness, right? What about porosity versus thickness versus absorbtion
> into the solder joint versus solder joint quality and reliability.
>
> Makes me yearn for Entek again no matter the visual, cleaning, life,
> storate, test, and all the other issues. Hell, It's flat and solders well
> even if it gets the pogo pins abit gummed up.
>
> Help appreciated - for us all insane folks in a diaganol world. Or, is
> everyone else really in a parallel world as Jack Crawford told me. If
> so, I'll park where I please. Damn, could be personal problem!
>
> Earl Moon
>
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