On 15 Dec 2010, at 16:57, Simao Cardoso wrote:
>
> You need big currents. Say 50 up to 100A in direct mode (3 times for
> reverse) for a 200x300mm (~100inch) board. Such circuit isn't easy and i
> never did anything similar... It seams an AC TIG welder... Other than
> that is the required voltage for the reverse pulse no matter how many
> hairs i pull off i just can't figure it out, it will be found by
> testing.
>
Do you have a reference for that current calculation, Simao ?
I was looking at
http://www.thinktink.com/stack/volumes/volvi/copplate.htm and they are quoting much lower currents. I was only actually trying to get a 100x160mm area plated (it's the limit of my CAD licence) but even 200x300mm comes out way short of 50A
According to their formula,
Current = [(200/25.4 ∗ 300/25.4 ∗ 2)/144] ∗ 20
=> 25.8A
For my (100x160mm) setup, it would be:
Current= [(160/25.4 ∗ 100/25.4 ∗ 2)/144] ∗ 20
=> 6.9A
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 :)
Cheers
Simon
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