Lum Wee Mei said:
>I am from Singapore. I am in-charge of a group of layout designer and have
>not heard of Hull Cell Scale.
>What is this item?
Well, I'm from Arkansas, but don't tell anyone, it might hurt my
credibility. It was completely in the other corner of the state from Bill,
I have relocated long ago to Texas.
A Hull cell is a small open tank which is used to test electroplating
solutions. A small (about 500 ml) sample of the solution is put in the
cell, and prepared anode and polished cathode plate placed in the cell,
then current is applied. The cathode is plated, results are used to
determine whether the plating solution is performing properly across a
range of current densities which vary because of the distance relationship
from the anode to the cathode in the Hull cell.
The plating will look thin and spotty in the low current density areas,
then begin to look OK, and become ugly again when the density is too high
resulting in "burned" plating.
The "scale" is a small clear ruler which shows the current density
(Amps/ft2) at different positions on the test (cathode) plate.
This permits small proportional changes in the plating bath chemistry to be
made and subsequently test results, predicting the best performance range
of the bath. It is of course more easily done in the small test cell than
in a large bath with hundreds of gallons of solutions.
Generally speaking, it is used to keep the organic addititives at the
proper level during production of the plating line, and Hull cell tests are
done routinely and periodically to determine the amounts to be added. If
the results are really bad, the bath can be carbon filtered or other
remedial action taken.
If any of this is wrong, remember I'm not under oath, and I may refuse
further testimony, change the subject, or start an armed conflict if
pursued.
regards,
Jerry Cupples
Interphase Corporation
Dallas, TX USA
http://www.iphase.com
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