Cleaning and Contamination Conditions

Question:

We are chroming some parts, and we have contamination problems because we are producing it in the same conditions as regular parts. Could you give me some tips about cleaning and contamination conditions? Thank you. F.V.

Answer:

I am not sure I fully understand your questions but believe you are cleaning all parts with the same process, then some are receiving a chrome plating. I am not sure what the end use of your other product is, but preparing a surface to receive chrome plating is a multi-step process that requires a part with a high degree of cleanliness. An activation treatment is usually necessary prior to chrome plating. At a minimum, this would involve acid etching of the surface prior to plating. A more thorough preparation would be an electrolytic etch. This can be done in a chromic acid or sulfuric acid bath prior to the rinsing and chrome plating. In electrolytic etching, the part will be the anode. Cathodes made from an insoluble material should be used.

Both sets of parts will contaminate the cleaning bath. Separating the cleaning in different tanks will slow down the contamination of the more critical cleaning prior to chrome plating. This could be slowed further by the use of skimmers, coalescers and microfiltration.