This is the first time I have used this e-mail system.  We are not plating
PCB's, we make compact disc, specifically the mold plate used to mold
compact disc.  We are not electroplating, we are electroforming, the metal
we are plating on is passivated so there is no bonding of the two metals.
The electroformed piece is completely seperate from its parent when
completed.  The mold plate or stamper as we call it has all the music
physically embedded on its surface, as microscopic metal forms (125
nanometers tall x 500 nanometers wide and .5 - 3 micrometers long).  The
nickel plates are 149mm in diameter and are plated at a max current of 48
amps to a thickness of 300 micrometers.  The current density runs about
27-28 amps/square decimeter.

The test we are performing with the hull cell uses stress tabs, a special
panel with 5 copper foils which only plate on their front sides.  The tab
closest to the anode tests the highest current density the tab farthest away
tests the lowest current density.  If set up properly the first and second
tabs (the closest) should curl towards the anode due to tensile stress the
third tab should remain strait and the fourth and fifth should be curled
away from the anode due to compressive stress.

The chart sent with the stress tabs reads as follows:

Amps    #1ASD   #2ASD   #3ASD   #4ASD   #5ASD
1.0     12      9.6     7.2     4.8     2.4
0.8     7       5.6     4.2     2.8     1.4
0.6     3.5     2.8     2.1     1.4     0.7
0.4     2       1.6     1.2     0.8     0.4
0.2     0.4     .32     .24     .16     .08

As you can see the 1.0 amp is the highest current for the chart and tests a
current density of 7.2ASD on the third tab.  My question is how do I
interpolate this chart to test 27ASD on the third tab.

Thanks for your reply, any help is appreciated,
Steve Schram
CD Mastering Manager
Universal Studios, Universal Music and Video Dist.

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