Why should paint be sprayed airlessly, and what are the requirements for airless spraying?

This post was last edited by Zhongyuanren on 2018-2-17 at 22:10. The differences between air spraying and airless spraying: Air spraying is a coating process that is widely used in paint application tasks today. Air spraying utilizes a stream of compressed air that passes through the nozzle orifice of the spray gun, creating negative pressure. This negative pressure draws the paint in through a suction tube and forces it out through the nozzle in the form of paint mist. The paint mist is then sprayed onto the surface of the parts to be coated, forming a uniform paint film. Air spraying can produce a uniform coat with a fine and smooth finish ； For the more concealed parts of components (such as gaps and irregular surfaces), the paint can also be applied evenly; the amount of paint applied is determined by the diameter of the spray gun. For larger topcoats, a spray gun with a 1.5 mm nozzle can be used, while for larger primers, a spray gun with a 2.5 mm nozzle is suitable. It is clear that the best way to significantly increase the paint output is to use a spray gun with a larger nozzle diameter. Film thickness uniformity: Film thickness uniformity is related to the gun movement speed and pattern overlap. The spray gun should be aligned with the workpiece surface and moved at a constant speed of 30–60 cm/s. Too fast will cause the coating to expose the underlying surface, while too slow will lead to sagging; a pause of 0.1s will result in severe sagging. Advantages and disadvantages of air spraying: The advantages are simple operation, high coating efficiency, and good quality of the coating film ； The disadvantages are high consumption of coating film, severe environmental pollution, harm to the health of operators, and the need to install additional environmental protection facilities. High-pressure airless spraying, also known as airless coating, is a spraying method that uses a high-pressure plunger pump to pressurize the paint, creating a high-pressure stream of paint which is then ejected from the nozzle in the form of an atomized spray that acts on the surface of the object (such as walls or wooden surfaces). Compared to air spraying, the paint finish is uniform with no granular texture. Due to being isolated from air, the paint dries and remains clean. Airless spraying can be used for applying high-viscosity paints, producing clean edges, and is even suitable for some spraying projects with specific edge requirements. Based on the type of mechanism, they are also divided into various types such as pneumatic airless spray guns, electric airless spray guns, and internal combustion airless spray guns. Powder coating involves using a powder spraying device (an electrostatic spray gun) to apply powder coating onto the surface of a workpiece. Under the effect of electricity, the powder adheres evenly to the surface of the workpiece, forming a powdery coating layer ； The powder coating is leveled and cured through high-temperature baking, resulting in a final coating with various effects (depending on the type of powder coating) ； The coating quality achieved through powder spraying is superior to that of painting in terms of mechanical strength, adhesion, corrosion resistance, and aging resistance, and the cost is also lower compared to painting when similar results are desired. From the above explanation, the original poster must now understand air spraying and airless spraying.