1. chemical etching: wrap the metal card with adhesive tape, carve out the metal part with a knife, put it in acid solution for about 1 hour, take it out with a clip, rinse it with clean water, and fold off the adhesive tape. The disadvantage is that the color will not look good after etching.

2. Electric meat cleaver: carving is enough. The disadvantage is that the failure rate is high, unless the hand is very manipulative.

3. Steel seal: The words on the steel seal are hammered into the metal plate.

4. Stamping: after the shape of the mold is made, the aluminum plate is cut into a certain shape, and then placed on the mold, and external force is exerted on the plate by pressure to make it plastically deform or separate, so as to obtain the metal signboard with the required shape, font and size.

5. Screen printing: screen printing is made by using screen as the base and photosensitive plate making method. When printing, the ink is poured into one end of the screen printing plate, and a certain pressure is exerted on the ink part of the screen printing plate by the scraper, at the same time, the ink moves to the other end of the screen printing plate at a uniform speed, and the ink is squeezed onto the metal sign from the grid of the graphic part by the scraper during the movement.

6. Laser engraving: take an aluminum plate, then use laser marking technology, and finally print words or patterns on the metal sign. Similarly, not only characters can be displayed, but also various complex patterns and other basic characters, physical and chemical parameters can be displayed.

All the above methods can be added to the metal card, and the specific methods should be selected according to the specific situation and needs.