In the process of spraying operation, improper operation of spray gun will affect the spraying effect of the product. Good spraying effect is shown in: 1. Average distribution of coating 2. Coating should not be too thick or too thin. Several problems to be paid attention to in Spraying:

The distance between the nozzle outlet and substrate is called gun distance. The smaller the gun distance, the greater the spraying pressure and the greater the impact of air pressure on the product, the uneven situation will occur in the coating, resulting in the problem of coating too thick. The larger the gun distance is, the smaller the spraying pressure is, and the paint is easy to lose, making substrate parts of the spraying material too small to reach the specified thickness. The spraying fan surface and the substrate surface are in a vertical state. When manually operating the spray gun, the spraying width cannot be too large, otherwise the problem of coating average will occur. The purpose of running the spray gun should always be parallel to the substrate surface, perpendicular to the spraying fan surface, unstable operation rate, uneven coating thickness, too fast operation rate, too thin coating, too slow operation rate, too thick coating. All in all, when using spraying equipment, you must achieve moderate strength and appropriate distance, so as to get the desired coating effect. After construction, some things that are done need to be improved, the cleaning of paint and aid equipment, and the remaining paint after use should be blocked and retained, which are all problems that need to be paid attention.

The main points that need to be paid attention to in the operation of the spray gun include: the moving speed of the spray gun, the control of the trigger, the distance between the gun and the posture of holding the gun, etc., which are described below:

I. The moving speed of the spray gun.

During the spraying operation, the moving speed of the spray gun has a great influence on the coating effect.

1. If the manual spray gun moves too fast, substrate the surface coating is thin, which makes it appear dry, thin, poor leveling, and coarse;
2. If the manual spray gun moves slowly, the coating film on the surface of substrate must be very late, and it is easy to cause flow hanging phenomenon.
3. The most ideal moving speed of spray gun is that after spraying, the surface coating of substrate is full, uniform and wet. This can only be controlled by operators with certain spraying experience.
II. Control of the trigger.
The spray gun is controlled by the trigger. Trigger the deeper the buckle, the greater the liquid flow rate. Static electricity spraying equipment in the process of traditional shooting, the trigger is always pulled to death, rather than half-button. In order to avoid the accumulation of paint sprayed out at the end of each gun run, experienced painting worker should loosen the trigger slightly to reduce the paint supply.
III. Orientation of spray gun to substrate surface.
The spray gun should remain vertical to the surface of the substrate, or keep it as vertical as possible. If the spray gun is a little skewed, the result will definitely cause the spray belt to flow on one side, while the other side will appear dry and thin, lacking paint, which is very likely to cause stripe-shaped coating.
IV. Interval between spray gun and substrate surface.
For siphon spray gun, the best working interval is 15~20cm. If the interval is too close, it may flow and spray metal glitter paint or pearlescent lacquer may even cause color inconsistency with expectations. If the interval is too far. If it exceeds 20cm, it may lead to dry spraying and overspraying, making the leveling property of the coating worse. If the sprayed metal is glitter paint, there may be the possibility of color change. The pressure-fed spray gun can be farther away from the substrate. Generally, the optimal interval is 20 to 30cm. These are the principles that must be followed during spraying construction.
5. Hold the gun.
The spray gun is held by Palm, thumb, little finger and ring finger, and the middle finger and index finger pull the trigger. Some painting worker change the way of holding the gun from time to time when working for a long time. Sometimes they only use thumb and palm to cooperate with little finger, sometimes they hold the gun with ring finger, and the middle finger and index finger are used to trigger. Static electricity spraying equipment this can relieve fatigue and improve work efficiency.^[3]