Bright etching of anti-rust aluminum is carried out in acid etching agents. Acid etching agents often use sulfuric acid, nitric acid, chromic acid and phosphoric acid. Nitric acid can easily cause large-scale tobacco production and pollute the environment. The use of phosphoric and sulfuric acid etching agents with sulfur-containing heterocyclic organic compounds can replace some nitric acid, such as gloss.
In alkaline etchants, caustic soda, soda ash and sodium phosphate are used, with a small amount of surfactant added. Rust-proof aluminum can generally be carried out in alkaline degreasers at temperatures exceeding 40°C.
Hydrogen peroxide and hydrofluoric acid can also be used, and hydrogen peroxide and acetic acid can also be used. For example, 45mL/L, 80mL/L, use hydrogen peroxide and acetic acid for 10~15s, soak at room temperature. Note that the operation should be carried out under ventilation conditions.
Rust-proof aluminum varieties require different etchants to be selected according to different materials during etching. In rust-proof aluminum etching, it is necessary to remove burrs, welding seams and casting surface residues using mechanical methods, and then perform degreasing and degreasing cleaning through alkaline degreasing.
The steps for etching anti-rust aluminum plates are as follows:
After drying, etching is performed.
Screen printing uses a cleaned aluminum plate, polyester or nylon monofilament mesh, fixes it on the screen frame with a stretcher, and then uses a sizing device to scrape and apply photosensitive glue 2-3 times.
After the coating film is dry, the black and white film with the photographed pattern is attached to the coating screen mesh. After exposure and development, the screen printing template is obtained.
Fix the aluminum plate and pattern template at the corresponding position of the screen printing machine, use alkali-soluble acid-resistant ink to print the required pattern, and let it dry naturally.
The screen printing ink must be removed after etching. Generally, acid-resistant ink is easily soluble in alkali, and the ink can be removed by immersing it for a few minutes.
After removal, if high brightness is required, it can be polished and then dyed.
After dyeing, in order to prevent discoloration and increase wear and corrosion resistance, transparent varnish can be sprayed.
The aluminum plate itself has good corrosion resistance and is not stained. It does not need to be coated with transparent paint, depending on actual needs. If it is required to retain the original color and gloss of the aluminum plate, after removing the ink and cleaning it, put it into a solution of 50% HN03 (volume fraction) and 50% H20 for 10-20 minutes for passivation treatment, so that the aluminum plate can be etched with pattern. With the new protective film, you can get decorative products.
