Metal finishing Q&As since 1989

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CuSO4 concentration of gravure bath increasing > 290 gpl although underutilised

We have copper plating bath for gravure cylinder preparation .It is under utilized for past few days , even though the CuSO4 concentration is rising (from 270 gpl to 319 gpl in span of 15 days). There have been some corrective actions by removal and dilution by DM water which have little impact on reduction in concentration. Please guide

A.ROY
COPPER PLATER - BANGLADESH
2007

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First of two simultaneous responses --

Only five probabilities and actions.
1- take the anodes out of the bath (they keep dissolving)
2- search for fallen copper objects at the bottom.
3- check bath level (water evaporation).
4- check for human error (accidental additions of salts)
5- check for intentional sabotage.

Guillermo Marrufo
Monterrey, NL, Mexico
2007

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Second of two simultaneous responses --

Dear

You must be (and you must ) keeping circulating pump on. (or anode will passivate) The copper anode dissolves in liquid and since there is no plating, concentration of CuSO4 increases fast. Remember there is H2SO4 in bath which can dissolve Copper. Do not worry. Do regular removal and add DM water without Chloride. Alternatively, there are baths which will plate out Copper continuously. It is common that copper bath concentration goes up even when you use bath normally and you have to do continuous removal.

Kaushik Magiawala
plating shop employee - Gandhinagar, India
2007

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2007

Mr Roy,
Sounds like your chloride level is too high, or sulfuric acid concentration is out of range. Both bath components, if too high, will dissolve the copper anode somewhat even though the bath is idle. I assume you are using hi-phos copper anodes that are bagged, and the air agitation is turned off when the bath is idle?
Check both the Cl and H2SO4. If you continue to have problems, you should pull the anodes or anode baskets when the bath is idle for a length of time. Be sure to dummy plate at LCD when the anodes go back in, to tighten up the anode film. Good luck to you, and let us know how you make out.

Mark Baker
Process Engineer - Syracuse, New York