Different types of metals have different etching processes, but the general process is as follows: metal etching plate → degreasing → water washing → etching → water washing → drying → screen printing → drying → water immersion for 2 to 3 minutes → etching pattern Text → water washing → ink removal → water washing → acid washing → water washing → electrolytic polishing → water washing → dyeing or electroplating → water washing → hot water washing → drying → soft cloth polishing (polishing) → spraying transparent paint → drying → inspection → finished product packaging.
1. Pre-etching treatment
The processes before metal etching are all pre-treatments. It is a key process to ensure good adhesion between the screen printing ink and the metal surface. Therefore, it is necessary to completely remove the oil stains and oxide films on the metal etching surface. Degreasing should be based on the oil contamination of the work piece. It is best to perform electrical degreasing before screen printing to ensure the degreasing effect. In addition to the oxide film, the best etching solution should be selected according to the type of metal and film thickness to ensure that the surface is clean. It must be dried before screen printing. If there is moisture, it will also affect the adhesion of the ink, and affect the effect of subsequent pattern etching or even aliasing, which affects the decorative effect.
2. Screen printing
Screen printing should produce standard pattern screen printing screen according to printing needs. In the pattern decoration process, the silk screen is mainly used for protection, and the photosensitive glue should be applied more often in order to make a thicker silk screen template, so that the covering performance is good, and the etched pattern has high definition. Under the action of light, the glue film of the screen plate produces a photochemical reaction, so that the illuminated part is cross-linked into a water-insoluble glue film, and the unilluminated part is dissolved by water to expose the screen space, so that the coated silk The screen pattern is lithographically engraved on the screen to conform to the pattern of the black and white positive film.
Fix the screen printing screen with pattern on the screen printing machine, and use alkali-soluble acid-resistant ink to print the required pattern on the metal plate, which can be etched after drying.
3. Post-etching treatment
The screen printing ink must be removed after etching. The general acid-resistant ink is easily soluble in alkali. The etching plate is immersed in 40-60g/L sodium hydroxide solution, the temperature is 50-80℃, and the ink can be removed after immersing 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 resistance and corrosion resistance, transparent varnish can be sprayed. For some metals, they have good corrosion resistance and are not dyed, and they can also be painted without clear paint, depending on actual needs.