(1) Preparation before painting
Before painting , prepare the necessary items for painting. The necessary items for painting include paint and thinner, paint mixer, weighing equipment, spraying equipment and accessories, painting and painting testing equipment, etc. . In addition to this, it is necessary to carry out the work of painting preparation and machine debugging.
1. Painting preparation
(1) Confirm the painting
Confirm the type and quality of the paint according to the coating requirements, and find the problem corrected in time.
(2) Adjust the viscosity of the paint
The paint is thoroughly stirred and the viscosity of the painting is measured. If the viscosity is too high, the diluent should be appropriately added to adjust the viscosity.
2. Sprayer installation and inspection
(1) Installation
Install and connect the components and auxiliary accessories of the prepared sprayer correctly.
(2) inspection
After the spraying machine is installed and connected, enter the state to be sprayed. Check whether the power source is running normally before spraying, then inhale the paint, check whether the high pressure paint cylinder is pressurized normally, whether the feed hose is leaking, whether the connection between the parts is tight, the spray gun and Whether the filter is blocked or not. Found faults and eliminated them in time.
(3) Painting environmental conditions control
The temperature and humidity of the sprayed environment are measured to meet the painting conditions and can be applied. Outdoor painting should also take into account the weather factors, from the spraying to the surface of the painting for a period of time, should avoid rainy weather and high wind speed, wind and sand.
(2) Painting operation
The painting operation is mainly the operation and use of the spray gun. The improper use of the spray gun can cause painting defects. The coating coating defects mainly manifest in three aspects:
First, the painting is uneven, mainly characterized by joint defects, inconsistent painting color, and poor painting smoothness.
Second, the painting is too thick, mainly characterized by sag phenomenon, the surface of the painting is dry and the deep layer is not dry, and the coating crust phenomenon occurs.
Third, the painting is too thin; the main performance is that after the conventional painting is applied, the coating does not reach the required thickness. There are three main issues to be aware of when using the gun.
1.Gun distance
The distance between the nozzle and the surface of the object to be coated is called the gun distance, and the gun distance is preferably 300~400mm. The gun distance is too small, the spraying pressure is too large, the recoil force is also large, the coating unevenness is easy to occur, and the spray width (the fan width) is small, so that the painted object is excessively sprayed too much, and the painting film is too thick. If the gun distance is too large, the spray pressure loss is large, the paint is easily lost, and the spray width is too large, so that the local spray of the painted object is too small, and the painting film does not reach the thickness requirement.
2. Spray fan angle
The spray fan surface and the surface to be painted should be perpendicular to each other. When the spray gun is manually operated, it should be noted that the spray width should not be too large each time. Otherwise, the operation angle may cause a significant change in the angle of the spray fan surface, resulting in uneven painting.
3. Spray gun running direction and speed
The direction of the spray gun should always be parallel to the surface of the object to be painted, perpendicular to the spray surface to ensure uniformity of the painting. The speed of the spray gun should be stable, preferably 300~400mm/s. The running speed is unstable, the painting thickness is not uniform, the running speed is too fast, the painting is too thin, and the painting is too thick.
