Even though many people refer to plating as an “art”, there is no doubt that sound scientific principles and practices are critical to successful plating finishes. The basics of electroplating start with an understanding of the metallurgical properties of the substrates to be plated. This is crucial because the most important process in plating is the pre-treatment of the substrate. The choice of cleaning chemistry is dictated by the alloy of the metal as well as the soils to be removed.
Soils such as oils, paraffins, and buffing compounds are normally encountered in the plating process, and the choice of cleaning chemistry should be geared towards the specific soils you want to remove. Some plating lines have a soak cleaner and an electrocleaner, which uses reverse current (anodic) to remove stubborn soils and scale.
Rinsing
Thorough rinsing with clean water is the next step once the parts are clean. Depending on the metal alloy being plated, the next step is either an acid pickle or deoxidizer to remove oxides from the surface as well as neutralize any alkalinity left from the cleaners. After thoroughly rinsing the parts with clean water, the parts are electroplated for a given amount of time to meet thickness requirements. After electroplating, the parts are thoroughly rinsed in clean water followed by any post treatments or secondary plating finishes, as in the case of nickel and chrome. The end of this entire process includes final clean water rinses and a drying stage to minimize water spotting or oxidation when plating parts such as tubes.
Understanding the type of metal alloys and soils for cleaning is the first critical step to successful electroplating. Throughout the process, clean flowing rinses are important to avoid contamination of processes down the line and maintain the integrity of a properly prepared part. In the electroplating bath, routine maintenance of the filters, anode bags, heaters, chillers and agitation equipment is necessary to maintain consistent quality. The “art” of plating certainly requires some basic fundamental scientific principles and practices, but it’s a great way to add value to your finished product.