In the process of spraying, improper operation of spray gun will affect the spraying effect of the product. Good spraying effect is shown in: 1. The coating distribution is average. 2. The coating should not be too thick or too thin.
The distance between the nozzle outlet and the coating is called the gun distance. The smaller the gun distance is, the greater the spraying pressure is, and the greater the impact of air pressure on the product, the coating will be uneven, resulting in the problem of too thick coating. The larger the gun distance is, the smaller the spraying pressure is, and the coating is easy to lose, so that the coated part of the spray material is too little, and the coating cannot reach the specified thickness.
The spray fan is vertical to the coated surface. When manually operating the spray gun, the spraying width shall not be too large, otherwise, the problem of average coating will occur. The purpose of spray gun operation shall always be parallel to the surface to be coated and vertical to the spray fan. If the operation rate is unstable, the coating thickness will be uneven. If the operation rate is too fast, the coating will be too thin. If the operation rate is too slow, the coating will be too thick.
In a word, when using the spraying equipment, we should make sure that the strength is moderate, and the distance is appropriate, so that we can get the desired coating effect. After the construction, some unfinished things also need to be improved, such as the cleaning of the coating and the help appliances, and the remaining coating materials should be blocked and retained after use. These problems should be paid attention to.
The key points 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 guns and the position of holding the gun, etc.
1. Movement speed of spray gun
In 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, the coating on the surface will be thin and dry with poor leveling and coarseness;
(2) If the moving speed of the manual spray gun is slow, the coating on the surface is sure to be late, and it is easy to produce the phenomenon of sagging.
(3) The best moving speed of the spray gun is that after spraying, the surface coating of the coated object is full, uniform and wet. This needs to be controlled by operators with certain spraying experience.
2. Control of the trigger
The spray gun is controlled by the trigger. The deeper the trigger is pulled, the faster the liquid flows. In the process of traditional gun using, the trigger of electrostatic spraying equipment is always buckled, not half buckled. In order to avoid the accumulation of coating sprayed at the end of using gun, experienced sprayers should loosen the trigger slightly to reduce the coating supply.
3. The orientation of the spray gun to the substrate surface
The spray gun should be vertical to the substrate surface, or as vertical as possible. If the spray gun is a little askew, the result will surely cause the spray band to flow to one side, while the other side will appear dry and thin, lack of coating, which is extremely likely to cause stripe coating.
4. The interval between the spray gun and the surface of the base material
For the siphon spray gun, the optimum working interval is15~20cm. If the interval is too close, it may produce flow, and even cause the color inconsistent with the expected when spraying metallic flash coating or pearlescent coating. If it’s too far apart. More than 20cm, it may lead to dry spraying, over spraying and poor leveling of the coating. If the metallic flash paint is sprayed, the possibility of color change may also exist. The pressure spray gun can be far away from the base material. Generally, the best interval is 20 to 30 cm. These are the principles that must be followed during spraying construction.
5. Holding the gun
The spray gun is held by the palm, thumb, pinky and ring fingers. The middle finger and index finger pull the trigger. Some spray painters change the way of holding the gun from time to time when they work for a long time. Sometimes they only use their thumbs and palms with their little fingers, sometimes they use their ring fingers to hold the gun, and their middle and index fingers are used to pull the trigger. Electrostatic spraying equipment can alleviate fatigue and improve work efficiency.