Francis,
Your plating thickness will depend largely on your cathode
current density,
not your anode area. However, if you try to force too much
current through
your anodes and you have insufficient anode area, then you
can create a
condition known as anode polarization.
The best remedy for
plating pwbs with different areas on each side is to
have separate
rectification. In this manner, you can control the amount of
current
for each side separately.
However, make sure your agitation on both sides
of the cathode is as uniform
as possible, that is no dead spots. Another
possible remedy here is to
outfit your plating cell with eductors, ratheer
than air spargers. Eductors
use pumps to cause a solution movement across the
face of the cathode. thus
you are getting a laminar flow, rather than a
turbulent flow. I have
performed controlled experiments where the
distribution is improved up to 20
%.
Best regards,
Michael
Carano
-----Original Message-----