Spraying jig operation skills

1. The purpose of mastering the correct operation skills of spraying jigs is to save paint, obtain coatings that meet the quality requirements, avoid the consumption of paint quality and physical strength, and reduce the probability of waste. Through correct paint operation skills training and turning this skill into a habit, not only can improve the production efficiency, but also improve the quality of the coating film. Below we will introduce the basic techniques used when using airless or general-purpose air atomization equipment.

2. Preparation before painting

The spray gun and related fixtures should be cleaned and should be in normal working condition. Check whether the spray gun produces the ideal spray pattern. The ideal spray should be symmetrical, uniform atomization, and clear edges. There are only a few paint mist particles outside the spray edge. The configured air compressor capacity should meet the requirements of the equipment manual. For example, the air consumption of GPQ6C type airless sprayer is 300～2500L/min, and 1.6～2.5m3 or 2.5m3 air compressor should be equipped. In order to ensure sufficient air intake, the inner diameter of the air outlet pipe of the air compressor and the air pipe connected to the inlet of the sprayer should not be less than the diameter of the air inlet pipe specified in the manual.

3. Pressure of spraying fixture

The conditions for reaching a suitable atomization air pressure: the minimum atomization pressure required to achieve the ideal atomization of the liquid. Therefore, the principle that should be followed when adjusting the pressure is: "The spray shape is good, and the set pressure is right" (the pressure should be as low as possible) is too high The pressure will not improve the quality of the coating, it will only shorten the life of the equipment and increase the wear of the nozzle, and will make the paint rebound, waste the paint and contaminate the space.

4. Spraying skills

①Overview

a. Before pulling the trigger, the gun should be in motion;

b. Keep the distance between the spray gun and the workpiece constant, not too far away or too close;

c. The spray gun should move at a constant speed during spraying;

d. When spraying the same job, the starting point of the first spraying stroke should be the same;

e. The surface of the workpiece should be covered by wet paint;

f. The overlap amount of adjacent spraying strokes remains the same;

g. For the same workpiece, the number of spraying strokes should be consistent;

②Distance of spray gun

a. The distance between the spray gun and the workpiece is approximately: ordinary air atomization, 15～20cm; airless spray atomization, 30～38cm

b. To obtain a wet, dark, and thicker coating, the spray gun can be kept closer;

c. To obtain a dry, lighter, and thinner coating, the spray gun can be farther away;

③Spray stroke

a. The movement trajectory of the spray gun is kept parallel to the surface of the workpiece;

b. The body of the spray gun is perpendicular to the surface of the workpiece, otherwise it will cause a waste of paint;

c. Do not let the spray gun move in an arc, to move the operator's forearms and shoulders, and not just use the wrist;

d. Adjacent spraying lines should have an overlap amount; for ordinary airless spraying, the overlap amount is 50%; for airless spraying, the overlap amount is 25%;

e. When the uniformity of the coating thickness is high, the cross spraying method should be used, and the spraying in the straight direction should be done first.

f. When spraying outside the air, pay attention to the wind direction, and the unsprayed surface should be below the wind to bring the flying paint and rebound to the unsprayed surface.

These basic skills only serve as an inspiration. Due to the huge differences in workpieces and coatings, users can determine their own spraying skills based on their actual situation and combining these basic principles. The operating instructions of each type of spraying equipment have explained the correct operation and maintenance of the equipment in detail. Here, only some issues that users tend to ignore are discussed.

1. Matters needing attention before the equipment is put into use

1. The capacity of the air compressor provided by the user should conform to the air consumption of the machine specified in the manual, and should be as large as possible than the consumption. The outlet pipe and the inlet pipe port should comply with the regulations in the manual in order to maintain sufficient air intake.

2. The compressed air from the air pressure is filtered and then enters the spray equipment, which helps to ensure the service life of the pneumatic system.

3. The paint should be filtered first. The filter should be selected according to the viscosity and particle size of the paint. If the filter is too fine, the paint will not pass through, and the spray gun will be easily blocked if it is too thick.

4. The air compressor should be as far away from the spraying site as possible to reduce the possibility of compressor contamination.

5. All airless spraying equipment should be well grounded to avoid static sparks.

2. Matters needing attention in the spraying process of fixtures and fixtures

1. During the spraying process, when cleaning, replacing the nozzle or not spraying, the spray gun trigger self-locking stopper should be locked in time. In any case, the nozzle of the spray gun is not allowed to face others to avoid injury.

2. Use the lowest possible spraying pressure. Excessive paint pressure will not improve the coating, but will only shorten the life of the equipment and increase the wear of the nozzle, and at the same time increase unsafe factors.

Three, the matters needing attention after spraying

After spraying, the equipment should be cleaned in time. The cleaning of pneumatic airless spraying equipment is generally divided into three steps:

1. Discharge of paint: Lift the suction pipe from the paint bucket, make the pump run without load, and discharge the remaining paint in the pump, filter, high-pressure hose and spray gun.

2. Rongji no-load cycle insert the suction pipe into the Rongji, and use the Rongji no-load cycle to clean all parts of the equipment.

3. To discharge the solvent, take the suction pipe out of the solvent barrel, and circulate without load to discharge the solvent.