I Screwed up...BIG TIME!
I screwed up and double counted the surface area. M_D is correct. The surface area is already accounted for when the power supply amperage is set.
To anyone following this thread, ignore this response. It is wrong!
(PS - M_D - Sorry for doubting you and thanks for correcting my error.)
M_D;
I understand what you are saying and at first look it appears to make sense, but mathematically it doesn't work that way.
Since it takes 720 minutes at 1 amp current density to grow 1 mil of surface per sq/ft of surface area.
If you anodize at 4.5 amps, it would take 160 minutes to grow 1 mil of coating per sq/ft of surface area. (720 minutes divided by 4.5 amps).
If you only want a .5 mil thickness, it would take 80 minutes per sq/ft of surface area. (160 minutes times .5 mils)
If you only have a surface area of 0.10 sq/ft, it would take 16 minutes (160 minutes per sq/ft times 0.10 sq/ft).
You have to cancel out the terms in order to get the correct answer. Under your formula, everything cancels out except the sq/ft, so your answer is 80 mins per sq/ft. It goes back to fractions and cancellation of terms.
To express it in this light, it would be (just the final part of the equation for simplicity. Excuse the periods, it was the only to get proper placement):
160 minutes per sq/ft.........................1
------------------------.....times.....---------------- [sq/ft cancel out] =
...........1...................................... ....10 sq/ft
160 minutes..............................1
----------------.....times.....---------------- [1's cancel out] =
........1.....................................10
160 minutes
--------------- = 16 min
......10
I hope this makes sense!
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