Selective spraying: accurate, no waste of materials. Mainly used for medium and large equipment. Coating equipment is usually very expensive and requires a lot of maintenance. The thickness of the coating is affected by four factors: coating properties, temperature, pressure and design structure of the device. Selective coatings can be used in a medium to wide range of applications. Generally speaking, sealing is unnecessary because paint is only used in selected areas of the circuit. The operating equipment used in it is more expensive than that used in general large-scale operations, and it requires higher maintenance costs than dip coating and spraying. The viscosity of the material, temperature, pressure and the structure of the dispersion head will all affect the thickness of the coating.

Automatic spraying of three-proof paint on the whole board: the spray can product is convenient for maintenance and small-scale production. Spray gun is suitable for mass production and is an economical way for medium-sized equipment. It is easy to protect the mold layer, but it is difficult to apply it to the bottom of the component and needs to be reworked. The thickness of coating is affected by the relative linear velocity of spraying device, material temperature and pressure. Spraying is usually used in medium-batch production, with high productivity and low production cost. Spraying is difficult to construct under parts and needs more maintenance. The type of feeding system, linear speed, material temperature and atomization pressure used will affect the thickness of application.