Simon Gornall wrote:
>
> Do you have a reference for that current calculation, Simao ?
> Now admittedly, this is for a DC plating environment, not a
> reverse-pulsed one, but my reading of the pulse-plating literature
> implied that pulse-plating ∗let∗ you increase the current (to get
> things done faster, which board-houses like). It didn't ∗require∗ you
> to increase the current. I could be wrong, of course :)
No. Just current densities i saw at various patents and papers. Like for
DC 1A per dm.sq max for chemistries without additives 75min time. Or
3A/dm.sq with additives and true phosphoric anodes 25min. Time also
depends on the copper thick you wish, these are for 25micrometer or 1mil
deposit IIRC.
Your 144 is 12x12 inch on a square foot and you must be using ASF values
(amps per square foot) for the current density. There are ~9.3dm.sq in a
foot.sq, so 20asf are ~2.1A/dm², thats a nice value for DC, 35minutes is
fast enough, but it should fall in the need-additives-category...
The patents and papers i follow for this chemistry say 4 to 6 A/dm.sq
direct pulse. With 100A i could burn 200x300mm (~100in.sq) boards dark
brown at 8.3A/dm.sq or 77.2asf on 10minutes for 1mil deposit :D
(if reverse pulses could replace additives)
My desire with this setup is to reach the 3A/dm.sq and 25~30 minutes and
avoid additives (the anodes aren't copper) and i wont mind to go slower.
I bought 5V 50A psu's, by design i can have one psu per anode (or just
one) with total of 100A max possible... For reverse i hope to only need
one psu but the design is capable to use 2 psu's for reverse pulse too.
So it's 48 to 72A according to the documentation (36A for my desire),
being oversized means room for tests and the cheap psu's, won't get too
hot, no other reason for the 100A value.