The concept of precision sheet metal processing and green sheet metal is advancing with the times. When we were young, we learned sheet metal craftsmanship. We used scissors to cut the seam of sheet metal. Even if the accuracy is not more than 1mm and the obvious hammer mark is not visible on the outside, it is a high level sheet metal worker. Later, with hydraulic shears and bending machines, the processing of parts is labor-saving, the surface quality after processing is uniform, and the appearance is very beautiful. Later, CNC shears and CNC bending machines appeared. The bending angle of the processed parts can be accurate to 0.1°, and the size can be accurate to 0.1mm or higher. There is no need to use trapezoidal screws or threads as before. Several times to adjust the positioning, thus saving a lot of time and materials. Up to now, there has been an automatic material warehouse, which can not only realize automatic feeding, but also automatically complete the warehousing according to the different thickness, material, and size of the parts to be processed.
Sheet metal processing
Passivation: When the sheet metal is electroplated with zinc, passivation is required to obtain a denser oxidation protection layer. The stainless steel plate itself has certain corrosion resistance, and it can be processed directly under normal circumstances, but it needs passivation treatment under specific occasions. If the boiler water tank uses SUS304 or SUS316, the parts still need passivation treatment to ensure that they will not rust at high temperatures. The passivation solution contains 5% nitric acid and 2% potassium dichromate, and there is 10% hydrofluoric acid in the two-in-one pickling passivation solution. The hexavalent chromium Cr6+ in potassium dichromate will seriously pollute the environment and cause serious harm to the human body (such as the reproductive system). Hydrofluoric acid is highly corrosive and can cause serious damage to teeth and bones. It can also corrode glass. At present, China has successfully replaced Cr6+ with Cr3+, thereby greatly reducing environmental pollution, and has replaced hydrofluoric acid with certain additives.
Paint spraying and powder spraying: Paint spraying is the construction after the paint and the solvent (or hardener are added). The paint is atomized by compressed air or electrostatic force and sprayed on the workpiece and attached to the surface. The solvent evaporates (or reacts with each other) After curing into a film. The disadvantage of this process is that the high content of VOC (Volatile Organic Gas) is harmful to the human body; the utilization rate of the coating is very low, only about 50%, which is a waste of resources. The electrostatic powder spraying does not require a large amount of thinner, the powder does not contain harmful substances, and the additives are cured to form a film after evaporation, which does not pollute the environment, the coating quality is good, the adhesion and mechanical strength are high, the corrosion resistance, the curing time is short, and the primer is not required The recycling rate of paint and powder is high. With the popularity and application of epoxy resin and polyester powder spraying, the appearance of sheet metal parts is comparable to that of spray paint, and the corrosion resistance is greatly improved. With China's increasing environmental protection requirements, many companies process the phosphated FePO4 into other chemical raw materials after two precipitations in the sedimentation tank, thereby reducing the environmental pollution of phosphating treatment.
Many spraying production lines have adopted robot operations, which not only reduces the damage to workers but also ensures the stability of quality. Now the powder recovery device has become the standard configuration of the coating line. It can absorb most of the powder through the filter element, and through the installation of solenoid valves and sensors, when the workpiece passes by, it sprays water and closes after passing, thus saving energy and 50%. % Of water.