How does one make measurements of the dull region in the Hull cell?  Our 
chemist tells me that, after the copper electroplating bath is 
"adjusted", his Hull cell should read or measure 0 - 3 millimeters.  I 
asked how precisely that length could be measured.  He didn't know for 
sure, but felt the measurement was relatively coarse and might not be 
good to more than one significant figure.  

We are trying to put our processes under SPC, where possible.  We have a 
way to do it for the plating bath, but need a good way to measure Hull 
cell dull region.  Thanks for any suggestions or ideas.  Anyone who wants 
to discuss further is welcome to contact me.

Louis Hart
Quality Assurance Manager
Compunetics
412-858-6117


.