How to maintain the automatic spray gun

In order to ensure that the pre-treatment system can operate with maximum efficiency and ensure the quality of surface treatment, it is necessary to maintain the key component of the system - the automatic spray gun nozzle from time to time. Once the nozzle maintenance is not timely, the spray state of the nozzle will be distorted, which will inevitably lead to waste of pre-treatment materials and decline of surface treatment quality. Learning to identify, solve and avoid nozzle failures can help companies save on pre-coating material costs, avoid energy waste, ensure product surface finish quality, and reduce equipment damage. Here are some maintenance tips for automatic spray guns:

1. Causes of nozzle failure

a. Erosion. When the liquid with high flow rate passes through the metal surface of the nozzle hole, it will erode the nozzle hole, causing the nozzle pressure to decrease and the spray state to become irregular. The probability of nozzle erosion depends on the hardness of the liquid, the type of chemical material used in the spray pressure and its application. In addition, particulate impurities in the liquid can also cause serious erosion of the nozzle.

b. Accidental damage. Improper use and untimely maintenance are the main causes of accidental damage to nozzles. Although the nozzle mouth is usually designed to be concave, the offset structure of the fan nozzle is easily damaged.

c. Corrosion. When using chemical materials to spray the workpiece. These chemical materials can also cause corrosion of the nozzle material.

d. Blocking. The build-up of chemicals and impurities on the inside or outside edges of the nozzle can cause nozzle blockage. This will affect the spray shape of the nozzle. This affects the spray pressure.

e. Temperature. If the nozzle works at high temperature or abnormal temperature for a long time, it will cause the nozzle to be damaged due to the softening of the material.

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2. Identification of nozzle problems

When the spray pump runs at its rated capacity, the spray pressure of the nozzle will decrease with the expansion of the nozzle aperture. For damaged nozzles, even if the actual flow rate of the nozzle exceeds 30% of its rated flow, the change in atomization state is difficult to identify with the naked eye. The best way to identify another 9 nozzle problem is to observe the pressure change on the spray line. When comparing different nozzles of the same pretreatment system, the location and accuracy of the pressure gauges are critical. Usually the pressure gauge should be placed at the front end of the spray line. When judging the pressure change on the spray pipeline, the spray pressure of the intact nozzle should be used as the benchmark, and the difference between the actual pressure and the reference pressure should be used to determine whether there is a problem with the nozzle.

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3. Elimination of nozzle problems

Since it is difficult to directly perceive the problem of the nozzle with the naked eye, the selection of the nozzle must first be paid attention to. After choosing the right nozzle, there is a complete maintenance and replacement program.

a. Regularly check the nozzle. This includes regular cleaning of the nozzle and regular inspection of the nozzle for cosmetic damage. Generally, the nozzles of the first few processes (such as pre-degreasing and degreasing) in the pretreatment production line must be inspected and cleaned every shift, and the frequency of inspection and cleaning of the nozzles in the subsequent processes can be appropriately extended.

b. Regularly replace the nozzle. The frequency of nozzle replacement depends on the environment in which it is located, the composition of the spray liquid and the material of the nozzle. If the temperature is high and the spray liquid contains impurities, the number of nozzle replacements is relatively frequent.

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4. Summary

The nozzle has a significant impact on the operation of the entire pre-processing system. If the nozzle has frequent problems, it will lead to an increase in the cost of materials, an increase in energy consumption and a decrease in the quality of the workpiece. Therefore, prevention, detection and timely resolution of nozzle problems are critical.