Pre-Finishing Operations

Virtually all products that are finished require some pre-finishing procedure such as cleaning, stripping, or pickling. Without a properly cleaned surface, even the most expensive coating will fail to adhere or protect the workpiece. Depending on the process being performed, the degree of cleanliness will vary. Finishing operations such as phosphating, chromating, or electropolishing do not require as high a degree of cleanliness as electroplating or electroless plating. For example, it would be unreasonable to set up the same system for phosphating and electroplating operations because the cleaning prior to phosphating is not as critical to achieving a finish of high quality. In some cases, cleaners that contain acids or alkalis can actually reduce the quality of the finishing process. In other words, the cleaning process should match the finishing operation so that cleaning is performed in the most economical way to meet requirements (Innes 1993).