For the application of casting coating, brush coating, dip coating, flow coating and spraying methods shall be selected according to the production requirements of castings and castings. In the application, the Baume degree is generally controlled as: Brush 85 ~ 100 °, spray 85 ~ 95 °, dip 75 ~ 85 °, flow 73 ~ 84 °.
(1) Brush method
This is the simplest and most reliable coating method for casting coating. The casting coating is directly applied to the sand mold and sand core with a brush. The coating efficiency is low, the technical requirements for operators are high, and the consumption of casting coating is small. Generally applicable to sand mold and sand core.
(2) Dip coating
It is a method of directly immersing the core into the casting coating to obtain the casting coating layer. The coating efficiency is high, it is suitable for mass production, it can realize mechanized automation operation, and it consumes more casting coating than brush coating. Generally only applicable to sand core.
(3) Flow coating
Also known as overflow coating. In this method, the circulating pump of the flow coater, which can circulate the casting coating, is used to transport the casting coating, and a specially designed nozzle is used to spray and coat the casting coating on the sand mold or sand core. The coating efficiency is high, it can realize automation, especially suitable for the coating of large sand mold and sand core. The consumption of casting coating is more than that of brush coating.
(4) Spraying method
It is a method to spray the fine droplets of casting coating onto the surface of core by spray gun. High coating efficiency, high requirements for operation technology and large consumption of casting coating. Only suitable for the core with simple shape.
Different casting production and casting practice correspond to different coating and application process. Several typical applications are listed as follows.
Casting coating is one of the most important casting raw and auxiliary materials, which plays a key role in ensuring the surface quality of castings. There are many factors that affect the technological properties of casting coating. The key technical indexes of casting coating have great influence on the quality of castings. The correct purchase and use of coatings are the basic requirements to ensure that the coatings play a role. High efficiency, environmental protection and economy are the important direction of paint development in the future. New molding technology, such as lost foam, V-process and so on, requires the development of the corresponding coating. The casting demand of high quality also requires the development of the corresponding casting coating. The casting coating is facing the best opportunity of development.