What are the precautions for Customized Shipping Container spraying?

2023-02-13 00:46:51

For example, when spraying the outer paint of the refrigerated Customized Shipping Container, the time of manual spraying of the front and rear cabinets must be arranged at the same time as the time of automatic roof spraying to avoid the generation of paint mist particles due to the time difference between the two. Another example is when spraying the interior paint in hot weather, in order to avoid the roughness of the inner surface of the left and right side panels, the correct procedure is: top panel ~ front panel - left and right side panels. Another example is to avoid the color confusion of the door frame, after spraying the inner and outer paint, close the door, and then spray the outer paint on the door frame.

The upper and lower materials on the outside of the Customized Shipping Container are the key parts of the entire painting operation, and it is also the focus of the Customized Shipping Container owner to check the film thickness. In order to avoid missed spraying or insufficient film thickness when spraying the left and right side panels or the front panel, first spray the upper and lower strips, especially the reverse side of the strips horizontally, and then spray vertically.

Spraying distance refers to the distance between the front end of the spray gun and the surface of the box. Generally, it should be 30~40cm. Keeping the spraying distance constant is an important factor to ensure uniform coating thickness. As a result, under the same conditions, the coating efficiency is high when the coating film is thick at a short distance. However, if the spraying distance is too short, the coating film will be too thick per unit time, and it is easy to cause the coating film disadvantages such as "sagging" and "wrinkled skin". On the contrary, The spraying distance is long and the coating film is thin and the efficiency is low. If the spraying distance is too far, the paint will scatter and the coating efficiency will be poor. In addition, because the paint mist particles run in the atmosphere for a long time, the thinner volatilizes more, resulting in rough paint surface and even lose light.

When spraying, the spray gun must be perpendicular to the surface to be coated. When the spray gun is running left and right, it needs to be kept parallel to keep the spraying distance constant. If the spray gun runs in an arc shape and the spray distance changes continuously, there will be obvious differences between the middle and both ends of the coating film.

In addition, the spraying distance is also closely related to the width of the fog. If the running speed of the spray gun and the spraying of the paint remain unchanged, the spraying distance gradually increases from near to far. The result will be that when the spraying distance is short, the spraying width is small and the coating film is thick; when the spraying distance is large, the spraying width is wide The coating film is uneven, and even "showing the bottom is flying"

In the Customized Shipping Container spraying process, each paint must reach its specified film thickness; the nozzle selected according to the specified film thickness has its fixed flow rate and spray width, so the moving speed of the spray gun is the main factor to control the film thickness, and it should be according to the coating Film thickness requirements determine the proper operating speed and keep it constant to achieve uniform film thickness. According to the long-term production practice of the Customized Shipping Container technology, all operators can master the reasonable movement speed of the spray gun. According to the author's observation, the time required to complete each side panel (6m long) is 5-6 minutes, that is to say, the speed of spray gun movement is 1.0-1.2m/min.

Because the coating film is thicker in the middle of the spray pattern, the edge is thinner. When spraying, the front and rear fog widths must overlap each other to make the coating film uniform. That is, after spraying the first row of mist panels, the second row of mist panels should overlap the first row of mist panels by 30% ~ 50%, in order to maintain the uniformity of the film thickness of the box. Figure 5-2 is a schematic diagram of the overlap of the spray mist width.