I agree with the enclosed assessment on crystals in the acid 
          copper bath and would go as far to suggest pulling anodes 
          out of the acid copper bath.  It is definitely NOT a case of 
          more is better with anodes.  Many brightener systems form 
          their acting ingredients at the anode and require a specific 
          anode current density, or a ratio of anode area to cathode 
          area.
          
          Has the cathode area you're plating gone down recently due 
          to product mix changes?  Is the copper concentration in the 
          acid copper bath rising?
          
          Also, check to see if your copper anodes are passivating 
          indicating poor connection or too much anode surface area in 
          the plating tank.  This check is simple.  Anodes pulled from 
          the tank should be black with anode film.  If they are 
          copper colored or gray, connection is poor or there is too 
          much anode area in the tank.
          
          Hope this helps.
          
          Dave Sullivan
          Rockwell Collins, Inc.
          
          [log in to unmask]


______________________________ Reply Separator _________________________________
Subject: Re: Acid copper bath
Author:  [log in to unmask] at ccmgw1
Date:    3/17/97 2:26 PM


Is this problem manifested by crystalization of copper on the anodes?  On the 
bottom of the anodes, right?  Is it more prevalent on some parts than on 
others?  Have you looked at the anode c.d., the cathode c.d. and the 
resulting anode-to-cathode ratio?  Is it high or low?  Have you tried anode 
shielding?  Have you tried different concentrations of sulfuric acid?, (this 
crystalization is the "common ion" effect, sulfate being the ion).
          
There could be several answers but I've seen anode shielding fix it.
          
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