January 29, 2019
Metal finishing involves applying coatings or treatments to metal part surfaces, changing the metal part’s characteristics, hardening the surfaces or inhibiting corrosion. For the metal finishing process to be successful, the underlying metal surfaces have to be completely clean. If contaminants such as grease or oil are present, the metal coatings may not adhere properly while the presence of particles may make the coating uneven. Ultrasonic cleaning systems can clean metal surfaces quickly and completely. While other cleaning methods such as chemical or mechanical cleaning may be used as well, ultrasonic cleaning is faster and does not require the use of chemical solvents, so it is more environmentally friendly.
Ultrasonic Cleaning and Different Metal Finishing Techniques
Electroplating is a common method for applying a thin metal film to metal parts. The part to be coated is placed in a bath and used as an electrode carrying the electroplating current. When the electric current flows, metal dissolved in the bath forms a thin film on the part to be plated. Contamination on the metal surface disturbs the action of the electric current and can result in uneven or patchy metal coating. Ultrasonic cleaning can remove such contaminants before the electroplating takes place.
Similar plating can be carried out with a chemical process. The metal part to be coated is placed in a chemical bath with the coating metal dissolved in the bath solution. During the chemical reaction, the metal comes out of solution and is deposited on the metal part. If the metal part is not completely clean, the metal is deposited on top of the contaminants and the film may peel off because it doesn’t adhere to the underlying metal. With ultrasonic cleaning, such contaminants are removed, and the deposited film adheres tightly to the part’s metal surfaces.
Another metal plating technique is to press a foil of metal onto part surfaces at high temperature and pressure. This metal cladding technique relies on the pressure to bring the two metals into close contact and the temperature to allow the metals to form bonds. If there are impurities or particles between the underlying metal and the cladding foil, the bonds will be weakened, and the cladding may not adhere properly. Ultrasonic cleaning can ensure that the bonds resulting from close contact of the metals can form and that the cladding adheres tightly to the metal part surfaces.
How Ultrasonic Cleaning Removes Contaminants
The metal parts to be coated have to be completely clean for coatings and cladding to adhere. In ultrasonic cleaning systems, the parts are immersed in a bath of pure water or a solution with a mild detergent. A high power ultrasonic generator transmits an electrical signal to an ultrasonic transducer that is placed in the bath and produces ultrasonic waves in the liquid at a selected frequency. The ultrasonic waves generate microscopic cavitation bubbles that produce a strong scrubbing action against the metal surfaces in the bath, dislodging particles and removing contaminants. The bubbles are active wherever there is cleaning solution and they can therefore penetrate into dead end holes, crevices and inside surfaces. Ultrasonic systems clean everywhere and remove all kinds of contamination.
Kaijo Has the Technology for Metal Finishing Ultrasonic Cleaning
Kaijo can help metal finishing facilities use ultrasonic cleaning to improve facility performance and output quality. The company has a complete line of ultrasonic cleaning systems and equipment and works with metal finishing manufacturers to customize standard components for their applications. Ultrasonic cleaners work quickly to allow shorter run times and increased throughput. Parts are cleaner than with traditional cleaning methods and the adherence of coatings is often improved. Kaijo offers free consulting for companies that want to include ultrasonic cleaning in their processing lines.