Explore Gravure Coating Process, Advantages & Uses
Today, LCD and OLED screens are widely used in products such as TVs, desktop computers, laptops, and portable game consoles. Their superior image quality and color accuracy make them preferred choices for displays. To protect the intricate electronic components inside these screens, a thin protective layer called the barrier film is applied. It shields the components from moisture and oxygen, extending their lifespan and maintaining screen quality.
It requires precise coating to produce a protective barrier film, which is the reason why the gravure coating method plays an important role in the production line. In this comprehensive article, we will explore the gravure coating process and its benefits across different industries.
What is Gravure Coating?
Gravure coating applies a wet, functional layer onto various substrates and then dries the material to form a solid, uniform film. It is a high-precision roll-to-roll coating setup that uses two cylinder rolls to apply the film with different solvents. It delivers excellent consistency even at high production volume.
By utilising the gravure coating method, the substrate can have functional effects with aesthetic visuals. For manufacturers seeking stable quality, high-volume output, and precise coating thickness, gravure coating remains one of the most efficient and reliable industrial coating methods.
Gravure Coating Process
To properly coat a smooth, consistent film on the substrate, a thorough gravure coating process is required.
Rotogravure Cylinder Preparation
In the roll-to-roll setup, one of the cylinder rolls is typically constructed with a steel core and a ceramic coating. The roll is engraved with precise cells, known as the rotogravure cylinder. The cells are created by laser or electromechanical engraving, and their size and shape determine how much liquid the roll can carry.
Common cell shapes include quadrangular and hexagonal. On the cross-section, the patterns can be sharp or normal calottes. The cell structures can be adjusted based on coat weight, coating liquid viscosity, and substrate features.
Rotogravure Cylinder Installation
After the rotogravure cylinder is properly engraved with the desired patterns, it is ready for installation on the coating machine. It will be installed on the coating pan, beneath the substrate and the impression roller.
Coating Liquid Supply
The rotogravure cylinder will be partially immersed in the coating pan, which serves as the container of the liquid. When the cylinder rotates, the cells on the rotogravure cylinder will be filled with the liquid.
Excess Liquid Removal
Next, the doctor blade, a thin strip that is installed beside the cylinder, will scrape off excess liquid on the surface of the rotogravure cylinder. By doing so, it ensures a clean and smooth coating on the substrate.
Coating Liquid Transfer
While the rotogravure cylinder rotates, the impression roller also presses against the substrate from above. As a result, the liquid will smoothly transfer onto it, forming a precise coating.
Drying
After the liquid is properly coated on the substrate, it will pass through the drying system to remove any remaining solvents in the coating. Moreover, the drying process also reduces the creation of cracks or bubbles on the surface, delivering a smooth surface.
Advantages of Gravure Coating
Adapting gravure coating methods brings enormous benefits to the production line. In this section, we will discuss how it affects the precision, efficiency, and quality.
Precise Thickness Control
Each cell delivers a fixed volume of liquid with accurate cell geometry and metering. As a result, the gravure coating allows precise control of the coating thickness. It is suitable for industries that require greater manufacturing precision.
Highly-consistent Quality
The mechanically controlled coating volume offers strong repeatability across long production runs. It effectively reduces defect rates and ensures uniform surface properties on every substrate.
Rapid Coating Cycles
The roll-to-toll setup allows continuous high-speed production, improving production efficiency even in large-scale manufacturing. Its stable transfer mechanism enables efficient coating cycles without compromising quality.
Wide Viscosity Range
To meet the requirements and manufacturing standards of different industries, manufacturers add solvents with various viscosities to the liquid. Gravure coating performs well with low to medium-viscosity liquids, offering a smooth coating process.
Applications of Gravure Coating
Many modern manufacturing industries rely on the gravure coating method to apply functional yet aesthetically appealing coats to their products. The major industries that significantly benefit from it are as follows:
Packaging industry
Packaging is one of the most important applications of gravure coating. It supports the precise application of adhesives and primers to the substrates, offering strong bonding ability. It allows gravure coating to deliver functional benefits to packaging materials. Common packaging applications include food packaging and retort pouches.
Industrial Films
In addition to barrier coatings, gravure coating also applies solvent-based protective varnishes that offer excellent resistance to chemicals and stains. Moreover, gravure coating is also used to create high-quality release layers, which are commonly applied in the semiconductor industry.
Electronics Industry
To protect intricate electronic products, manufacturers apply functional layers that enhance component safety. Gravure coating can layer antistatic and conductive coatings on the products, which effectively reduce static electricity and prevent product damage.
Medical Field
Safety and cleanliness are key factors in the medical field. Thus, using gravure coating to apply antimicrobial or protective coatings is an essential step. These coatings prevent bacterial growth, and gravure coating also produces breathable barrier layers that are commonly used in breathable medical tapes.
Why Choose Webcontrol’s Dry Laminating Machine?
Gravure coating remains one of the most reliable and versatile technologies for producing high-quality and functional films. It delivers a wide range of benefits, such as precise thickness control, consistent performance, and an efficient coating cycle, making it irreplaceable across industries.
To meet the evolving demands of modern manufacturing, Webcontrol offers a high-quality dry laminating machine around a gravure coating station that controls liquid volume and keeps coating consistency stable. We engineer the DL Series to run solvent- or water-based adhesives through this coating station, pair it with an efficient drying tunnel, and reach machine speeds up to 200/250 m/min for food, medical, and sterilizable packaging.
For food packaging, the DL Series supports retort pouch production. For medical packaging, we apply antimicrobial coatings and produce breathable medical tapes. In industrial films, our gravure coating lays down protective varnishes and semiconductor release layers, and in electronics, it applies antistatic and conductive coatings.
Please contact us for more information on coating technology and machine setup.
FAQs
A: Webcontrol Machinery Corp. builds our gravure coating cylinders with a steel core and ceramic coating, engraved by laser or electromechanical methods into quadrangular or hexagonal cells. A doctor blade removes excess coating liquid before it transfers onto the substrate, which gives us precise thickness control and highly consistent quality across the run. The process finishes in drying, and it works across a wide viscosity range at rapid coating cycles.
A: Yes, Webcontrol Machinery Corp. applies our gravure coating technology across food packaging, medical packaging, and sterilizable packaging on the DL Series, and it also serves industrial films and electronics. For medical applications, this includes antimicrobial coatings and breathable medical tapes. For electronics, we apply antistatic and conductive coatings, and for industrial films, protective varnishes and semiconductor release layers. The gravure coating station applies a wet, functional layer through two cylinder rolls in a roll-to-roll setup, working with different solvents to fit each application.