Application of electrostatic painting technology on motors
Painting is a link in the production process of electric motors. Due to the guidance of national environmental protection policies and the improvement of people's occupational health awareness in recent years, the improvement of painting links has become the goal of many motor manufacturers.
Electrostatic painting technology is a new technology that has been developed rapidly in the world in recent years and is widely used in the surface treatment of various industrial industries. Compared with the traditional painting process, it can not only save materials, but also improve the level of environmental purification, and can make the spraying process mechanized, continuous, reduce the poor rate of spraying, and obtain excellent coating effect. Electrostatic painting technology greatly improves labor productivity and improves working conditions, thus obtaining considerable social and economic benefits. From the perspective of user experience, it can better meet the needs of enterprises in various industries.
At present, the traditional liquid spray and manual hand spray operation methods have problems such as large amount of paint waste, serious environmental pollution, difficulty in cleaning, low production efficiency, poor color of products, and unstable quality. Electrostatic painting can solve these problems. Its principle is the same as electrostatic dust removal, and it is a new technology for painting with the electrostatic field formed by high voltage. Compared with manual painting, it has the advantages of high efficiency, less waste, good quality and good health for workers.
1, the basic principle of electrostatic painting
Electrostatic painting is based on the object being coated as a positive electrode, which is grounded under normal conditions; the coating atomizing device is a negative electrode, which is connected to a negative voltage of the power source, thus forming a high-voltage electrostatic field at both poles. Since the corona discharge occurs at the cathode, the sprayed coating medium can be charged and further atomized.
In accordance with the principle of “same-sex repellent, opposite-sex attraction”, the charged coating medium is subjected to an electric field force, and the coating forms an encircling effect on the object to be coated, and flows along the power line to the positively-coated object to form an appearance. A layer-averaged, adherent film.
Electrostatic painting technology can also adopt positive polarity corona discharge, but the critical voltage of negative corona discharge is lower than that of positive corona discharge, and it is more stable and less prone to sparking. The object to be coated is normally grounded as a positive electrode.
2, electrostatic paint features
● Advantages
(1) The paint film is even and full, and the adhesion and decorative properties are good.
(2) High production efficiency, good working conditions, multiple electrostatic spray guns fixed installation, multiple simultaneous spraying, easy to achieve semi-automatic or automated, compared with compressed air painting, production efficiency is more than 10 times higher than manual painting, and thoroughly Get rid of the heavy labor of manual painting (painting), especially suitable for large-scale assembly line operations.
(3) Improve the utilization rate of paint, the utilization rate of paint materials can reach 80~90%, generally save about 60% of paint by hand spray paint, reduce the fog and pollution of paint mist, and improve the sanitary conditions of labor.
(4) The paint film has high quality and good adhesion, especially the paint film is uniform and smooth.
●Flaws
(1) For workpieces with complex shapes, the concave holes are not easy to be sprayed, and the convex portions are uneven in paint film, which often requires process adjustment or manual repair.
(2) Need a complete set of painting equipment, large investment
(3) Electrostatic spray paint maintenance management requirements are strict, improper operation or poor management is prone to electric shock, high voltage breakdown discharge, and even cause fire accidents.
●Safety items that must be paid attention to
(1) Voltage and current control. When using, the voltage should be controlled below 90,000 volts. Exceeding this voltage will be detrimental to human health. In addition, the short-circuit current should be controlled below 0.7 mA. (2) When spraying by hand, the spray gun should be in contact with the ground immediately after use, and the residual charge should be released in time, and the human body should not be insulated from the ground. (3) The distance between the workpiece to be coated and the mouth of the spray gun should not be too close. Keep it 10cm or more to prevent short circuit from sparking. (4) Before the operation, be sure to check whether the line connection of each part is normal. Be sure to pay attention to the normal grounding of the casing and workpiece to avoid high-voltage static electricity.
