The UV spray vacuum coating production line is a production line integrating automated spraying, ultraviolet curing and vacuum coating processes. It is mainly used for surface coating treatment of plastic, metal and other workpieces to enhance the decorative and performance of products. Here is its detailed introduction:

1.Process flow

• Single UV process: Feeding → preheating → flame dust removal → automatic static and electrostatic dust removal → automatic spraying of treatment agent → preheating → primer → standing →IR (infrared) baking →UV curing → discharging → vacuum coating → secondary feeding → electrostatic dust removal → topcoat → standing →IR baking →UV curing → discharging.

• Double UV process: feeding → preheating → flame dust removal → automatic static and electrostatic dust removal → automatic spraying of treatment agent → preheating → primer coating → standing →IR baking →UV curing → discharging → vacuum coating → secondary feeding → preheating → electrostatic dust removal → spraying of topcoat → standing →IR baking →UV curing → discharging.

2.Components

• Conveying system: Chain conveyor belts or roller conveyor belts are usually adopted, which are responsible for successively transporting workpieces from the feeding area to the spraying area, curing area and discharging area, ensuring the smooth movement of workpieces during the production process.

• Spraying system: including spray guns, spraying robots and paint supply systems. The spraying robot can be flexibly adjusted according to the shape and size of the workpiece, and achieve uniform spraying on the surface of the workpiece through programming control.

• UV curing system: Composed of multiple ultraviolet lamps, it is installed in the curing area. The wavelength and power of the UV lamp can be adjusted according to different types of coatings and process requirements to enable the coating to cure rapidly in a short time.

• Waste gas treatment system: It is used to purify the waste gas and volatile organic compounds (VOCs) generated during the spraying process. Common equipment includes activated carbon adsorption devices and catalytic combustion devices to ensure that the emissions meet environmental protection standards.

• Control system: Composed of PLC (Programmable Logic Controller), touch screen and various sensors, it realizes the automated management of the entire assembly line and coordinates the operation of each link such as workpiece conveying, spraying, curing and waste gas treatment.

3. Core workflow (taking lipstick tubes/eyeshadow boxes as an example

3.1 Pre-treatment: Ensure the adhesion of the coating

This step is the key to avoiding subsequent paint peeling and blistering, especially for the commonly used ABS and PP plastic substrates in cosmetic packaging.

Feeding and positioning: Manually or mechanically, the packaging items to be processed (such as the outer shell of a lipstick tube) are fixed on a dedicated fixture to ensure stable position during transportation and no deviation in spraying.

Substrate cleaning: Dual cleaning through "flame dust removal + electrostatic dust removal". Flame treatment can activate the surface of plastics and enhance the adhesion of coatings. Electrostatic precipitators remove surface dust and oil stains, preventing particle defects after spraying.

Preheating and drying: After cleaning, the packaging items are sent into the preheating furnace (with a temperature of approximately 40-60℃) to remove the moisture on the surface of the substrate and prevent pinholes from appearing in the coating during subsequent spraying.

3.2 First UV spraying and curing: Primer + initial setting

Its main function is to form a smooth base layer, providing a uniform substrate for subsequent vacuum coating.

Primer spraying: Use automatic spray guns or spraying robots to precisely spray UV primer (mostly transparent or light in color). The thickness of the coating should be controlled at 5-10μm to ensure coverage of the substrate texture while avoiding sagging.

Flow leveling: After spraying, the packaging items enter the flow leveling area (room temperature, stand for 10-20 seconds) to allow the coating to naturally spread out and eliminate the spray gun marks.

UV initial curing: Enter the UV curing oven and be exposed to a UV lamp with a wavelength of 365-405nm (power adjusted according to the coating). The primer curing is completed within 1-3 seconds, forming a hard base layer.

3.3 Vacuum coating: Achieve metallic/pearlescent effects

This is the core step for cosmetic packaging to "show texture", and common effects include gold, silver, and iridescence, etc.

Vacuum environment establishment: The cured packaging items are sent into the vacuum coating machine and evacuated to a high vacuum state of 10⁻³-10⁻⁴Pa to prevent impurities from affecting the coating effect during the coating process.

Coating deposition: Through "magnetron sputtering" or "evaporation coating" technology, metal targets (such as aluminum, chromium) or compound targets (such as titanium dioxide, to achieve pearlescent coating) are heated and vaporized, allowing atoms to evenly adhere to the surface of the packaging, forming a film of 50-100nm.

Cooling out of the chamber: After the coating is completed, slowly release the vacuum and cool to room temperature to prevent the film from cracking due to temperature differences.

3.4 Second UV spraying and curing: Protection + color adjustment/special effects

This step not only protects the fragile metal film but also achieves a customized visual effect, which is in line with the brand tone of cosmetics.

Secondary cleaning: After being removed from the vacuum machine, electrostatic dust removal is carried out again to eliminate any trace amounts of dust that may be generated during the coating process.

Topcoat spraying: Spray different UV topcoats as required, such as transparent protective paint (to enhance wear resistance), colored paint (matching brand colors), matte/frosted paint (special texture), with a thickness controlled at 8-15μm.

Secondary leveling and curing: Repeat the "leveling and setting →UV curing" process, extending the curing time to 2-5 seconds to ensure a tight bond between the topcoat and the metal film. The final coating hardness can reach over 3H (pencil hardness test).

3.5Back-end inspection and blanking

Quality inspection: By manual or machine vision inspection, check whether the packaging has problems such as missed spraying, scratches, color differences, and uneven coating. Non-conforming products enter the repair process.

Material cutting and packaging: Qualified products are removed from the fixture, undergo surface dust removal, and then proceed to the subsequent assembly or finished product packaging stage.

4.Features

4.1 High-efficiency production: UV curing is fast, usually taking only a few seconds to complete the curing process, which significantly shortens the production cycle and enhances production efficiency.

4.2 High-quality coating: UV coatings possess outstanding physical and chemical properties such as high hardness, wear resistance and corrosion resistance, which can significantly enhance the quality and durability of the workpiece surface.

4.3 Environmental protection and energy conservation: The UV curing process does not require heating, resulting in lower energy consumption. Moreover, the content of volatile organic compounds in UV coatings is relatively low, which helps to reduce exhaust emissions.

4.4 High degree of automation: By adopting advanced automatic control technology, it can achieve high-precision and high-consistency spraying effects, reducing errors and instability caused by human operation.

4.5 Strong flexibility: The spraying robot and adjustable UV curing system enable this assembly line to adapt to workpieces of different shapes and sizes, meeting diverse production demands.

5.Application field

UV spray vacuum coating production lines are widely used in industries such as consumer electronics, auto parts, and smart wearables, for surface coating treatment of products like mobile phone casings, car taillights, electric shavers, and children's smartwatches.

6.Core Driving Forces and Future Directions

The integration of UV coating and vacuum coating technologies represents a significant trend in the surface treatment field towards high efficiency, high quality, environmental friendliness and multi-functionality. This combined production line combines the advantages of both processes and has an extremely promising future development prospect.

6.1Innovative fusion of ultimate appearance and performance:

The future development will go beyond the simple "primer + coating" model and move towards creating unprecedented textures. Through precise control, advanced effects such as dynamic color (changing with viewing angle), depth touch (such as the combination of soft touch and metallic luster), and micro-nano texture optics (such as diffraction, structural color) can be achieved. Vacuum coating layers (such as titanium nitride, zirconium oxide) will also endow the surface with higher wear resistance and scratch resistance, extending the product's lifespan.

6.2Comprehensive Empowerment through Intelligence and Digitalization:

This composite production line will serve as a model of intelligent manufacturing. By integrating machine vision for automatic defect detection and leveraging AI algorithms to optimize hundreds of parameters such as UV curing energy, coating thickness, and speed, it achieves adaptive adjustment of the process window. A digital twin system is established, enabling process debugging and simulation production of new products in a virtual environment, significantly reducing the R&D cycle and enhancing the first-pass yield.

6.3Deepening the Emphasis on Green Sustainability:

Composite technology itself represents an environmental upgrade. UV coatings have almost zero VOC emissions, and vacuum coating replaces traditional electroplating, eliminating heavy metal pollution at its source. In the future, material innovation will be the focus, such as developing water-based UV resins, bio-based coatings, and exploring chromium-free and nickel-free coating targets, to create a consistently green manufacturing process that meets increasingly strict global environmental regulations.

6.4Disruptive expansion in application fields:

This technology will break through the existing scope of consumer electronics and automotive interiors and penetrate into more high-value-added fields. In the field of smart homes, it will create an integrated and high-quality appearance; in new energy vehicles, it will be used for lightweight and aesthetically pleasing interior and exterior parts; in the medical equipment field, it will provide coating solutions that are antibacterial, chemically resistant, and have excellent appearance.

7.conclusion

In summary, the development of the UV-vacuum coating production line is a path from "process superposition" to "system innovation". Through the deep integration of materials, processes and intelligent technologies, it not only meets the market's extreme pursuit of product appearance and functionality, but also promotes the entire manufacturing industry to transform and upgrade towards green, intelligent and high value-added directions, becoming an indispensable core technology link in high-end manufacturing.

Contact: Miss CHEN  / Foreign Trade Sales 

Phone: 86 18062064808

Email: Tina@lionpvd.com

WebSite: www.vacuum-coatingmachines.com

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