Electrostatic spraying process in the valve industry
Posted by: FEIHONG Powders |on August 28, 2012
In recent years, with the continuous development of science and technology, domestic valve market, but also to the high-tech, high-parameter, resistant to strong corrosion, the direction of the high life. This development direction also put forward higher requirements to the coating of the valve. Electrostatic spraying technology is the market for this material is ductile iron valves ordinary approach, this year is also the surface treatment of the valve has been widely promoted, but without careful analysis of a variety of materials and process before due to the electrostatic spraying equipment manufacturing, Because the different characteristics of different materials and processing technology in the choice of the electrostatic spraying equipment requirements. It requires more than the overall performance of electrostatic spraying equipment, routine optimization of the requirements of environmental protection, powder recovery rate on the powder should be concerned about the coating requirements required to deal with different types of artifacts unique development of the industry and market conditions and so on.
Here I summarized as follows few precautions will the domestic valve electrostatic spraying in:
- The pre-treatment process. Casting molding method of processing the surface oxide and sand blasting. Try not to use the shot blasting method. Valve requires higher accuracy, especially in the interior of the valve, there will be some local point shot blasting less than. Sandblasting better control of surface roughness and smoothness. But its efficiency is relatively slow its drawbacks. General requirements for the surface finish to achieve Sa3 level, the surface roughness Ra value of 45 ~ 70um.
- Degreasing and phosphating machining must not be less. If the local surface oily surface before entering the powder room, first appeared the oily coating significantly thinner. Followed by poor film adhesion, and easy to swap. Finally, the coating color difference is obvious.
- The valve castings Usually relatively thick, and must have a sufficient preheating time is required. This point is generally easy to overlook. Must be reasonable on the overall design of the powder coating pipeline valve Preheat oven to run enough time.
- For large valves for outdoor, require heavy-duty, thermosetting powder coating selection can not be for the sake of cheap powder coating so users should use pure epoxy powder coating, and requirements issued by the manufacturer of the authority inspection reports. In the case of the same coating methods, indoor powder coating used in the outdoors, the coating life of ordinary circumstances 6 months. The use of heavy-duty powder can reach more than three years.
- Valve coating problems. Many manufacturers pay attention to the appearance of color, and did not really pay attention to the quality of the coating. In fact, the main color and powder, but also important and spraying methods.