The construction process of automatic spraying equipment pipeline requires strict control of each step and parameter to ensure the quality and performance of the final coating. At the same time, the effective control of dust pollution is also a part of the construction process that cannot be ignored.
1.Workpiece pretreatment
Pretreatment is the primary task before spraying, the main purpose is to remove oil, rust or other coatings on the surface of the workpiece to ensure that the base metal is completely exposed. This step is crucial because it provides a good adhesion base for the subsequent spraying process.
2.The workpiece preheating
Preheating is a key link in the spraying process, and its time depends on the specification and quantity of the workpiece. Thick-walled, high-number workpieces require longer preheating times, while thin-walled, low-number workpieces are relatively short. This is because the total heat required for different weights of the workpiece is different when heating, and it is necessary to ensure that each workpiece reaches a state of thermal balance. The preheating temperature is very important to the thermal spraying effect, too low will lead to uneven coating, too high may cause the phenomenon of flow hanging and carbonization, affecting the film performance.
3.Spraying
Spraying is the core link of automatic spraying equipment pipeline, which requires precise control of multiple parameters. The first is the amount of powder spray, which is a key factor in determining the thickness and uniformity of the coating. When thermal spraying, the amount of powder spray is usually large, generally between 200 and 300g/min. In addition, the distance between the spray gun and the workpiece, the number of spraying times and the trajectory of the spray gun must also be accurately mastered. Too far away will lead to low powder rate, and too close may cause rebound. Spraying times and gun running track directly affect the uniformity and thickness of the coating.
In addition to the above parameters, powder recovery is also a part of the spraying process that cannot be ignored. When thermal spraying, the powder rate is usually only about 50%, and the remaining powder will be scattered in the spray room or in the air. In order to control dust pollution, the dust collection outlet of the spray room should be set in the upper part of the spray room, and specially designed according to the characteristics of the workpiece to be coated and the spray construction method.
