Switch Panel UV Coating Line

Switch panel UV spray coating line is an advanced process based on ultraviolet curing technology for surface coating, which is featured for high efficiency, eco friendly and high quality coating. AFNT ltd has offered multiple switch panel coating solutions for both coloring and vacuum metallization as well as the latest skin feel solution.

Technical Advantages

• Efficient production: Fast curing speed, significantly shortening production cycles.
• High-quality coating: high hardness, wear resistance, corrosion resistance, improve the surface quality of the product.
• Environmental protection and energy saving: low VOCs emissions, energy consumption is 75%-90% lower than traditional coatings.
• High degree of automation 😛 LC control system to achieve high-precision and high-consistency spraying operations.

Switch Panel Coating Process

• Surface Pretreatment: Clean and sand the substrate to remove oil and impurities, ensure a smooth surface, and improve adhesion.
• Primer spraying: Spray UV primer, assist leveling by infrared light, and then cure with ultraviolet light.
• Topcoat Spraying: Spray the topcoat as needed, ensuring uniform color and no sagging and bubbles.
• UV curing: Specific wavelengths of UV light are irradiated to quickly cure the coating into a hard coating.

ITEM	CONFIGURATION
Core Device	Chain spindle uv coating line(with spray booth, uv oven and chain conveyor) Robotic uv coating system(by reciprocator or painting robot)
Core Data	Line speed: 0.5-6m/min adjustable UV wave length: 320-400nm Paint thicness: 10-30μm(dry film) Applicable coating: UV base/top, water base coating
Safe Device	Emergency stop UV radiation protect(sealed curing chamber + observation window) Ex proof electric(grounding resistance≤4Ω)
Filtration Device	Waste air filtration(Water curtain+active carbon)

Switch panel UV coating process indepth explanation

Surface pretreatment
This is the basic part of the entire process, including cleaning and sanding treatment. Solvent cleaning is used to remove grease and dust from the surface of the substrate. Ultrasonic cleaning or plasma cleaning techniques are often used to ensure a clean surface.

Primer spraying
Spray the primer on the pretreated surface, and the selection of primer should be appropriate according to the product material and requirements. Spraying requires uniform coverage, and after spraying, it needs to be dried or pre-cured by UV to increase surface adhesion and smoothness. The spraying parameters (such as air pressure, spray distance, and spraying speed) need to be precisely controlled.

Top coat spraying
After the primer is cured and base coat is sprayed, a top coat(normally uv coating) is applied for protection and varnishing purpose. UV topcoat spraying requires uniform and consistent color, smooth and free of sagging and bubbles.

UV curing
Immediately after the spraying is completed, it enters the UV curing process, which triggers a photochemical reaction through UV irradiation of a specific wavelength (usually UVA band, wavelength range 320-400nm), so that the coating cures in a few seconds. Curing systems are typically equipped with multiple sets of adjustable UV lamps, and the power and wavelength can be adjusted according to coating properties.

UV spray coating process for switch panels is widely used in:

• High-end switch socket manufacturing: Provide wear-resistant, anti-fingerprint UV coatings for panels to enhance product texture and durability.
• Smart Home Products: UV spraying can achieve a balance between touch sensitivity and protective performance, making it an ideal surface treatment solution for smart switch panels.
• Automotive electronic switches: meet the strict environmental requirements of the automotive industry (temperature resistance -40~85°C, chemical corrosion resistance).

Common problems and solutions

In actual production, the switch panel UV spraying process may encounter the following typical problems:

Dragging: It is manifested as the coating flowing downward on the vertical surface to form tear stains. The main reasons include low viscosity of the paint, too thick spray, and too high ambient temperature.

Solution: Adjust the viscosity of the coating (add thixotropic agent), control the thickness of the single layer wet film (≤120μm), optimize the spraying parameters (air pressure 0.4-0.6MPa, spray distance 15-25cm), and improve the construction environment (temperature 20-28°C).

Bubbles: Tiny bubbles or holes appear in the coating film. The main reasons are that the solvent evaporates too quickly, the air is mixed into the paint, and the bottom layer is not sufficiently dried.

Solution: Adjust the volatilization rate of the solvent (add slow-drying solvents such as cyclohexanone), let the bubbles escape for 20 minutes after spraying, control the drying time between layers, and ensure that the bottom layer is completely cured.

Poor curing: The coating is sticky or insufficiently hard. The possible reasons are insufficient UV light intensity, lamp aging, paint photoinitiator mismatch, etc.

Solution: Check the status of the UV lamp (usually 800-1000 hours of service life), ensure that the light intensity meets the standard, and select a coating formula that matches the UV light source.

Poor adhesion: the coating peels off easily. The main factors include inadequate surface treatment, incompatibility of substrates with coatings, and excessive curing.

Solution: Enhance surface cleaning and sanding, use suitable primers, optimize curing parameters to avoid excessive cross-linking.