Gravure Printing

Gravure printing is a high-quality concave printing technique where images are engraved into grooves on a metal printing cylinder (plate). After ink is filled into the grooves, excess ink on the surface is removed by a doctor blade, leaving only the ink in the grooves, which is then transferred to the surface of a substrate (such as plastic film, metal foil, paper, etc.).

This technology is suitable for continuous, high-speed roll-to-roll printing, especially for mass production, and is commonly used in food packaging, pharmaceutical packaging materials, labels, and decorative films. Gravure printing is characterized by high print quality, color saturation, and excellent resolution, but the initial plate-making cost is relatively high.

A roll-to-roll gravure printing machine is a continuous, high-speed printing device suitable for mass production on flexible roll materials (such as plastic film, metal foil, and paper). Its printing principle involves etching or laser engraving an image or text onto a metal printing cylinder. Ink fills the recessed dot structure, and excess ink is removed by a doctor blade before the ink is transferred from the cylinder to the substrate surface.

This technology features high printing resolution, saturated colors, and compatibility with various materials and inks. Combined with roll-to-roll continuous production, it enables high-efficiency, large-area printing and is widely used in the following industries:

• In-mold/out-of-mold decorative films (IMD / OMD)
• Functional thin films and optical films
• Flexible electronics and sensing components
• Food and medical packaging
• Solar thin film elements

Gravure printing, combined with roll-to-roll processing technology, enables high-speed, continuous, high-volume printing, and has a wide range of applications, mainly including:

• Food packaging: such as potato chip bags, biscuit packaging, prepared food packaging, etc.
• Packaging for daily necessities: such as shampoo refill packs, wet wipes outer packaging, etc.
• Pharmaceutical and medical packaging: such as aluminum foil packaging, patch bags, and medical consumable packaging.
• Packaging for skincare and cosmetic products: Small-capacity designs such as face mask pouches and trial packs.
• Decorative printed materials: including wallpaper, gift wrapping paper, decorative film, etc.
• Labels and shrink films: applications include bottle labels, sealing films, heat shrink sleeves, etc.
• Industrial films: such as functional coated films, insulating films, anti-counterfeiting films, etc.
• Flexible electronics related products: including conductive circuits, RFID antennas, sensing layers, etc.

Our company specializes in gravure printing applications for industrial films, including structural pattern printing (such as fine lines and alignment patterns). Using roll-to-roll production technology as our core process, we provide highly stable and precise printing services, dedicated to meeting the special printing needs of the industrial market for technical films. Through efficient and consistently high-quality continuous processing, we help our clients enhance the added value of their products.

Advantages:

• High-speed continuous production
  It can operate 24 hours a day without interruption, making it particularly suitable for large-volume printing needs and offering high production efficiency.
• High printing quality
  It enables high-resolution, detailed graphics and stable color control, making it particularly suitable for precision patterns and functional printing.
• Suitable for a variety of materials
  It can be printed on a variety of flexible roll materials, such as plastic film, aluminum foil, PET, and paper.
• Suitable for functional coating and processing
  In addition to image printing, it can also be integrated with varnishing, anti-counterfeiting, conductive layer, and insulating layer technologies, and is widely used in the electronics and industrial fields.
• High stability and high degree of automation
  Equipped with tension control, automatic overprinting, and drying systems, the production process is highly controllable.
• Long-run printing costs are low
  Although plate-making costs are high, the average cost decreases significantly as print volume increases, making it particularly suitable for medium- to long-term production plans.

shortcoming:

• High plate-making costs
  Initially, metal molds need to be engraved, which is not conducive to the needs of small-batch, diverse, or short-term, fast delivery.
• Changing the pattern is not easy
  Each design requires a separate plate, making it less flexible than digital printing or flexographic printing.
• Large equipment investment
  Roll-to-roll equipment is expensive and requires a long time to recover the investment.
• Ink and solvent treatment must comply with regulations.
  When using solvent-based inks, it is necessary to consider exhaust emissions, volatile organic compound (VOC) recovery, and environmental regulations.

Sage focuses on the field of functional plastic films, possessing profound gravure printing and roll-to-roll process technology. It specializes in producing a variety of materials, including water transfer printing pattern films, IMD (In-Mold Decoration) films, OMD (Out-of-Mold Decoration) films, and high-quality PVA blank films. These materials are widely used in 3C electronics, automotive interiors, home appliance panels, and industrial decoration, and Sage is committed to providing stable quality and high-value-added solutions.

Gravure printing

• Graphics and images are engraved onto a metal cylinder using engraving or laser etching (the recessed parts are filled with ink).
• It can achieve high-resolution patterns, gradient effects, and fine lines.
• Suitable for non-absorbent roll materials such as plastic film, metal foil, and PVA water transfer film.
• This is a high-speed roll-to-roll continuous printing method, suitable for mass production.
• Initial plate-making costs are high, but unit production costs are low.

Flexographic printing

• Using a flexible relief printing plate, the graphic and text areas are raised.
• Suitable for various substrates: paper, plastic film, aluminum foil, etc.
• It offers fast printing speed and inexpensive plate making, but its detail reproduction is slightly inferior to gravure printing.
• Commonly used in food packaging, toilet paper packaging, and labels.

Offset printing

• The principle of oil-water incompatibility means that the image and non-image areas are on the same plane.
• Suitable for printed paper products, such as magazines, books, and flyers.
• The colors are natural and the dots are fine, but it is not suitable for non-absorbent materials such as plastic films.
• Non-continuous roll-to-roll printing, usually sheet-fed printing.

Letterpress Printing

• In traditional printing methods, the images and text are raised.
• Suitable for printing business cards, labels, and small-batch single-sheet printing.
• The effect is rather simple, with slight indentations on the surface (visual and tactile characteristics).
• It is now rarely used in industrial production and has been gradually replaced by gravure and flexographic printing.

If your product is:For functional decorative films such as plastic films, water transfer films, IMD films, and OMD films, gravure printing is the most suitable printing method because it has high resolution, high-speed continuous production capabilities, and can stably produce patterns and functional layers in large quantities.

Gravure printing is a printing technique that uses recessed image areas to transfer ink. Its working principle can be divided into the following steps:

• Plate making (engraving)
  The images and text are etched or laser-engraved onto a metal cylinder (called a plate), forming a fine, recessed dot structure.
• Ink filling
  As the rollers rotate, ink flows into these recessed graphic areas.
• scraper ink
  A doctor blade scrapes away excess ink from the surface of the roller, leaving only the ink in the recessed areas.
• Imprint transfer
  The roller comes into contact with the substrate (such as plastic film, paper, etc.), and under pressure, the ink is transferred from the groove to the substrate, completing the pattern printing.
• Drying and rewinding (if it is roll-to-roll printing)
  The ink is immediately dried by hot air or an IR oven, and the printed material is then rewound by a rewinding machine.

Suitable for non-absorbent materials such as plastic films, metal foils, and PVA films. Gravure printing is often used in conjunction with roll-to-roll continuous production systems, enabling efficient high-speed, high-volume manufacturing, and is widely used in the printing processes of functional films and decorative materials.

In gravure printing, the process of creating a printing plate involves "engraving" the design or text onto a metal cylinder (plate body), making it a recessed area that can hold ink, allowing the ink to be correctly transferred to the film or substrate.
The overall process can be roughly divided into the following steps:

• Image and text processing
  The original design is converted into printable image data, and then adjusted and processed with halftone color separation.
• Roller preparation
  Use copper or iron rollers and electroplate a copper layer on the surface (to facilitate engraving).
• Carving method selection
  • Chemical etching:After the image and text are transferred to the photosensitive layer by exposure, grooves are etched out using an acidic solution, which can create a deeper printing plate and achieve higher saturation for large areas of printed color blocks.
  • Laser engraving / Electronic engraving:High-resolution graphics and text can be directly engraved using lasers or diamond needles, making the production process relatively fast.
• Chrome plating
  To improve wear resistance and extend service life, a layer of hard chrome is plated on the surface after engraving.
• Polishing and Inspection
  Perform micro-polishing to ensure a smooth surface, and check dot depth and uniformity to ensure stable printing.

Plate making is a crucial front-end process in gravure printing, affecting image resolution, ink thickness, and print quality stability. Although it has higher initial costs, the plate has a long lifespan, making it particularly suitable for high-volume, high-quality production needs (such as roll-to-roll printing applications like water transfer film and IMD film).

Gravure printing is a technology centered on "high-speed continuous roll-to-roll printing," boasting extremely high production efficiency and stability, making it particularly suitable for large-scale, high-precision industrial processes. Its main characteristics are as follows:

Printing speed performance:

• Typical speed range: 100~600 meters per minute
• High-speed models: up to 800 meters per minute or more
• Supports 24/7 uninterrupted roll-to-roll production, suitable for long-term, high-volume operations.

Production efficiency characteristics:

• The roll-to-roll continuous feeding and winding design significantly reduces material changeover and downtime.
• Printing and drying are carried out simultaneously, quickly completing multi-color overprinting.
• High registration accuracy and color consistency make it particularly suitable for functional films that require high detail and tonal range.
• Long plate-making life (gravure cylinders can be reused hundreds of thousands of times), high cost-effectiveness.
• The larger the production volume, the lower the unit cost, making it suitable for medium to ultra-large-scale production.

Scope of application:

• Flexible materials such as plastic films (e.g., PET, PP, PE), PVA films, water transfer films, IMD films, and OMD films.
• Especially suitable for products with highly repetitive patterns and exquisite surface details.
• Widely used in 3C decorative films, automotive interior films, home appliance panel films, and special function coating substrates.

In gravure printing, a series of technical controls and management measures are necessary to ensure accurate and stable colors. The following are the key control points:

Ink Management:

• Use highly stable inks to avoid color differences caused by changes in temperature and humidity.
• Real-time monitoring of ink viscosity is typically achieved through an automatic viscosity control system (Viscosity Controller).
• To avoid excessively rapid evaporation of ink solvents and maintain consistent printing concentration.

Printing conditions settings:

• Strict control of printing pressure, squeegee angle, and squeegee pressure is essential to ensure uniform ink transfer.
• Maintain stable surface temperature of the printing plate and machine operation to avoid color differences caused by thermal expansion or cooling.
• Precise tension control is set between each color unit to prevent substrate deformation from affecting printing accuracy.

Color Management Process:

• Color sampling is performed according to international color standards (such as Pantone or custom color charts).
• The color difference is quantitatively measured using a spectrophotometer, and the allowable range of ΔE is set.
• Establish a color digital standard profile (Target Profile) as a basis for printing color comparison.

On-site operations and inspections:

• Color samples are randomly inspected every hour or per batch to detect deviations as early as possible.
• A color standard (First Article Approval) is set at the beginning of printing to ensure it is followed throughout the entire process.
• Introducing an automated vision inspection system to detect color differences and printing defects in real time.

In gravure printing, color control is a complete process that includes ink management, equipment conditions, digital color standards, and on-site testing.
Especially for high-requirement products such as water transfer printing film and IMD film, this color management is crucial to ensuring consistent product quality.

The cost calculation for gravure printing involves multiple fixed and variable cost factors. Especially in roll-to-roll mass production, the overall cost decreases significantly with production volume. The main components are as follows:

Main cost items

Plate-making cost (gravure cylinder production)

• The largest fixed cost in the initial stage depends on the engraving process (mechanical etching/laser engraving) and the number of colors.
• A single monochrome roller costs between several thousand and tens of thousands of New Taiwan Dollars.
• It can be reused hundreds of thousands of times, resulting in low cost per batch after amortization.

Material costs

• Includes printing substrates (such as PET, PVA, TPU, etc.) and inks.
• Material loss rate needs to be included in the calculation (approximately 1-3%, depending on the product and machine condition).

Ink and solvent usage

• The more colors used, the higher the cost, calculated based on the pattern coverage and printing area.
• Some special colors (such as metallic, pearlescent, and masking colors) are more expensive.

Electricity and consumable costs

• Electricity consumption includes ovens, mechanical operation, and air compressor systems.
• Consumables such as tension control equipment, scrapers, and viscometers also need to be replaced regularly.

Labor and maintenance costs

• Man-hours required for operators, machine setup, and quality inspection
• Regular machine maintenance and downtime repair costs

Utilization rate and production efficiency

• The production line operates continuously with high efficiency and has a better ability to spread fixed costs.
• The yield rate directly affects the unit cost (low yield rate leads to scrap and rework).

Cost optimization suggestions

• Long-run printing saves money over time; it is recommended to group similar styles and designs together in the same schedule.
• Establishing a standard color library and reusable roller modules can reduce the cost of repeated plate making.
• Precise control of ink concentration and machine speed improves registration accuracy and reduces scrap rate.

Gravure printing has high initial plate-making costs but low subsequent mass production costs, making it ideal for plastic film products that require large-volume, high-quality consistency, such as water transfer film, IMD film, and OMD film. If production line management and design are well integrated, the overall production cost can be highly competitive.

Color Variation

• Phenomenon:Inconsistent color depth in the same or different batches of printed materials
• Possible reasons:Variations in ink viscosity, unstable machine speed, inconsistent drying temperature, and different ink batches
• Solution:
  • Use an automatic viscosity control system (Viscosity Controller)
  • Controlling ink concentration and solvent evaporation rate
  • Stabilize machine speed and temperature, and standardize ink batches.

Registration misalignment

• Phenomenon:Color misalignment and blurry patterns during multicolor printing
• Possible reasons:Abnormal tension control, printing plate setting error, material elastic deformation
• Solution:
  • Adjust tension zones and implement an automatic overprint detection system.
  • Confirm that the angle and height of each color plate are set correctly.
  • Controlling material temperature to prevent thermal expansion

Ink Splashing

• Phenomenon:Ink splatter and blurring at the printing edges
• Possible reasons:Printing speed too fast, improper doctor blade settings, ink too thin
• Solution:
  • Reduce machine speed or use low-splatter ink formulations
  • Adjust the scraper angle and pressure
  • Stabilize ink viscosity

Contamination

• Phenomenon:Dust, black spots, and impurities appear on the printed surface.
• Possible reasons:Materials attract dust due to electrostatic attraction, unclean working environment, and ink tank contamination.
• Solution:
  • Install dust removal equipment and static eliminators.
  • Regularly clean the printing environment and equipment
  • Filter ink and clean the ink system regularly.

Uneven coating

• Phenomenon:The same printed material may have alternating light and dark areas or a blurred pattern.
• Possible reasons:Inconsistent engraving depth on the printing plate, uneven scraper pressure, and unstable surface tension of the material
• Solution:
  • Inspection and replacement of the body
  • Fine-tune the scraper pressure or replace the scraper blade.
  • Perform surface treatment on the substrate (such as corona treatment).

Gravure printing is a high-precision, high-speed process, and even the slightest deviation in settings can lead to quality issues. By standardizing operating parameters, implementing automated control systems, and conducting continuous quality inspection, overall yield and printing stability can be significantly improved, which is especially important for demanding applications such as water transfer films, IMD films, and functional films.

While gravure printing boasts advantages in mass production and high-speed operation, it also comes with a certain degree of environmental impact. The following are its main environmental impacts and corresponding mitigation measures:

Potential environmental impacts

Solvent evaporation (VOC emissions)

• Traditional gravure printing uses inks with volatile solvents (such as toluene and ethyl acetate).
• After volatilization, it produces volatile organic compounds (VOCs), which are harmful to human health and air quality.
• High-temperature drying processes can easily result in the discharge of large amounts of solvent.

Energy consumption

• High-temperature drying and high-speed operation are required, resulting in relatively high overall power consumption.
• If energy recovery systems are not used effectively, carbon emissions will be high.

Exhaust gas and odor problems

• The printing area and oven may release odors and organic gases, which require proper ventilation and treatment.
• Potential impact on the work environment and surrounding air quality

Printing waste liquid and waste

• Cleaning the printing plate and system generates waste ink, detergent, and wiping cloths.
• Improper handling could pollute water sources and soil.

Environmental improvement measures

• Switching to low-VOC or water-based inks significantly reduces the release of harmful gases.
• Introducing a solvent recovery system improves recycling rates.
• High-efficiency drying ovens and heat recovery systems are used to reduce energy consumption.
• The printing workshop is equipped with activated carbon adsorption equipment or RTO (regenerative thermal oxidizer) to treat waste gas.
• Implement waste liquid classification and outsourced treatment to avoid environmental pollution.

Corporate Sustainable Development Direction

• Research and development and introduction of environmentally friendly inks (such as water-based and UV-based inks) for use in functional films.
• Incorporate "environmental protection and energy conservation" into production process optimization and machine upgrade standards.
• Strengthen ESG policies and obtain international environmental standards such as ISO 14001 and carbon footprint certification.
• Reduce energy consumption and scrap rate by implementing smart manufacturing technologies (IoT, MES).

Gravure printing has clear advantages in high speed and mass production, but its environmental impact cannot be ignored. Through equipment upgrades, ink transformation, and emission control technologies, its negative environmental impact can be significantly reduced, moving towards a greener and more sustainable production model.