The process flow of the UV paint automatic spraying line generally includes the following steps:
Pre - treatment of workpieces:
Cleaning: Remove oil, dust, and other impurities on the surface of workpieces to ensure good paint adhesion. This can be achieved through methods such as solvent cleaning or ultrasonic cleaning.
Degreasing: Use degreasing agents to remove grease and oil stains on the surface of metal workpieces, which helps to improve the wettability of the paint on the surface.
Rust removal: For workpieces prone to rust, rust - removing agents are used to remove rust on the surface to prevent rust from affecting the painting quality.
Surface activation: Increase the surface activity of workpieces through methods such as chemical treatment or mechanical sanding to improve the adhesion of UV paint.
Spraying of primer:
Primer preparation: According to the process requirements, prepare the appropriate UV primer, adjust its viscosity and other parameters to ensure good spraying performance.
Automatic spraying: The primer is sprayed onto the surface of the workpiece through an automatic spraying device. The spraying equipment can adjust the spraying amount, spraying pressure, and spraying distance according to the size and shape of the workpiece to ensure uniform spraying of the primer.
Drying and leveling: After spraying the primer, the workpiece enters the drying and leveling section. Usually, infrared (IR) drying is used to pre - dry the primer to a certain extent to make the primer film evenly distributed on the surface of the workpiece and improve its leveling property.
Spraying of topcoat:
Topcoat preparation: Select the appropriate UV topcoat according to the product requirements, and adjust its color, gloss, and other properties to meet the final product appearance requirements.
Fine - spraying: Use an automatic spraying device to spray the topcoat onto the surface of the workpiece that has been sprayed with the primer. In this process, strict control of the spraying parameters is required to ensure the uniformity and thickness of the topcoat, and to avoid problems such as uneven spraying and dripping.
IR leveling: After spraying the topcoat, the workpiece is subjected to IR leveling again to make the topcoat film more uniform and smooth, and to improve the surface quality of the coating.
UV curing:
UV irradiation: The workpiece after spraying the topcoat enters the UV curing area and is irradiated by ultraviolet light of a specific wavelength. The photo - initiator in the UV paint absorbs ultraviolet light energy, generates free radicals, and initiates a cross - linking polymerization reaction, so that the paint film is quickly cured from a liquid state to a solid state6.
Curing control: Strictly control the UV irradiation intensity, irradiation time, and conveyor speed to ensure that the UV paint is fully cured. The appropriate curing conditions need to be determined according to the type and thickness of the paint and the characteristics of the workpiece.
Post - treatment:
Quality inspection: Visually inspect the surface of the workpiece after curing to check for defects such as cracks, bubbles, and uneven gloss. At the same time, perform performance tests on the coating, such as hardness, adhesion, and abrasion resistance tests, to ensure that the product quality meets the requirements.
Packaging: Pack the qualified products and transport them to the warehouse for storage or delivery according to the packaging requirements.
In the entire process of the UV paint automatic spraying line, the key lies in the precise control of each process parameter to ensure the quality and performance of the coating. At the same time, regular maintenance and calibration of the equipment are also required to ensure the stable operation of the production line.
