The Technique of Automobile Spray Gun (2)

4. The moving speed of the spray gun.

The moving speed of the spray gun is related to the drying speed of the paint, the ambient temperature, and the viscosity of the paint. Generally, it should move at a constant speed at about 30cm/s. Moving the spray gun too fast will cause the coating to be too thin, while moving the spray gun too slow will cause sagging.

5. Spraying pressure.

The correct spraying air pressure is related to the type of paint, the type of thinner and the viscosity after dilution. Generally, the air pressure is adjusted to 0.35-0.5MPa or determined by the test spray. If the pressure is too low, it is very likely that the atomization will not be good, and the thinner will evaporate too slowly. The paint will be sprayed on the surface of the workpiece like rain, which is prone to "tears", "pinholes" and "bubbles". However, if the pressure is too high, it is very likely to over-evaporate, and even worse the dry spray will form sometimes.

6. The spraying method, the control of the route.

Spraying methods include vertical overlap method, horizontal overlap method, and vertical and horizontal alternate spraying. The spraying route should be done in the order of "from high to low, from left to right, from top to bottom, first inside and then outside". Close the spray gun at the end of the route. The route of the second one-way movement of the spray gun is opposite to the first one. The spray gun nozzle set is flush with the edge of the first route, and the upper half of the mist shape overlaps the lower half of the first mist shape. The overlap of the two moving routes should be about 1/3 or 1/2.

7. The basic movements of moving the gun.

In the car repair coating, the condition of the object to be coated is different so the method of moving the car paint spray gun is also different. The following describes several commonly used methods of how to move the spray gun.

(1) The method of moving the spray gun at the edge of the component. When spraying on the edge of the component, spraying from right to left is generally used, and also use the vertical spraying (the sprayed paint is in a vertical direction).

(2) The method of moving the spray gun of constructing the inner corner. Spray from top to bottom of the construction, and use horizontal spray (spray the paint in a horizontal direction).

(3) The method of moving the spray gun of small and upright plane component. The spraying must be from top to bottom, then from left to right, then from bottom to top, and finally completed in sequence.