What is the importance of pretreatment of chromium plating?
Pre-treatment: All processes before plating are called pre-treatment, whose purpose is to trim the surface of the workpiece, remove the grease, rust, oxide film, etc., on the surface of the workpiece.
Provide the required plating surface for subsequent deposition of the coating.
Pre-treatment mainly affects the appearance and binding force. According to statistics, 60% of defective electroplating products are caused by poor pre-treatment.
Therefore, pretreatment plays an important role in electroplating process. In countries with developed electroplating technology, great importance is attached to the pre-treatment process.
The pretreatment process accounts for half or more of the whole electroplating process, so the coating with good surface condition can be obtained and the defect rate can be greatly reduced. Sand blasting: remove rust, welding slag, carbon deposit, old paint layer, and other dry oil stains on the surface of parts; Remove sand and oxide skin from the surface of castings, forgings or heat-treated parts; Remove burrs and directional wear marks on the surface of parts; Reduce the roughness of parts to improve the adhesion of paints and other coatings; The part is diffuse reflection extinction state Polishing: To remove burrs, rust, scratches, welds, bumps, sand holes, oxide skin and other macro defects of parts to improve the flatness and plating quality of parts. Polishing: The purpose of polishing is to further reduce the roughness of the surface of the parts and obtain a bright appearance. There are mechanical polishing, chemical polishing, electrochemical polishing and so on. Degreasing: remove grease from workpiece surface. There are organic solvent oil removal, chemical oil removal, electrochemical oil removal, wipe oil removal, roller oil removal and other means. Pickling: remove surface rust and oxide film.