The critical role of the folder-gluer process

In the production of corrugated cardboard boxes, precision in the folder-gluer process is critical to ensure the quality of the finished product. The blank – the die-cut and printed sheet of cardboard ready to be folded and glued – enters the folder-gluer machine, where adhesive is applied to the initial flap. From this point, the forming box must be guided in a stable and controlled manner until it is completely closed.

The “fish tailing” issue in conveyor belts

The conveyor belts play a crucial role in this process. If not properly designed, they can deviate laterally during operation, causing the phenomenon known as fish tailing, where the belt oscillates like a fish tail. This movement can result in the blank slipping, misaligned folds, irregular gluing, and box deformation, leading to increased waste and machine stoppages.

The solution: “no fish tailing” belts

The use of “no fish tailing” belts, made of high-strength composite materials with dimensional stability, ensures that the blank remains perfectly aligned throughout the production line. In many industrial applications, this solution can reduce waste by 20–25% compared to lines using standard belts, improving both production continuity and the quality of the final product.

High-pressure gluing systems: precision and speed

Equally important is the gluing system. SIPACK machines utilize high-pressure gluing systems, capable of applying adhesive precisely and uniformly along the score lines. This ensures a fast and durable bond, minimizes the risk of insufficient glue or smearing, and allows operation at high speeds without compromising joint quality.

Coordination between transport and closing

During the closing phase, the no fish tailing belts guide the blank accurately to the counter ejector, the section of the machine responsible for collecting and stacking the closed boxes in bundles, ready for transport or subsequent packaging operations. This coordination between high-pressure gluing and controlled transport ensures uniform, perfectly closed boxes, optimizes process repeatability, and minimizes manual intervention and machine stoppages.

Conclusion: efficiency, quality, and production continuity

In summary, the integration of no fish tailing belts and high-pressure gluing systems is a key factor in ensuring reliability, productivity, and consistent quality in modern folder-gluer lines, meeting the precision, speed, and standardization requirements of today’s packaging industry.

Anilox, ink management and process stability

In corrugated board converting, print quality is no longer just an aesthetic matter. Today it represents a concrete competitive factor. Packaging for e-commerce, retail and food applications requires results that are increasingly consistent, repeatable and reliable over time.

In this context, the flexo folder gluer plays a central role: it is the point where technical choices, materials and operational expertise translate into the final result. In particular, three elements directly influence print quality: anilox, ink management and print process stability. Alongside these factors, the quality of the printing plates, printing pressure and the characteristics of the board itself also have a significant impact on the final result.

The strategic role of the anilox in corrugated board printing

The anilox is the first real regulator of print quality. Its role is not simply to transfer ink, but to do so in a consistent and predictable way, reducing variability throughout the production process.

The key parameters in selecting an anilox are:

• Cell volume, which determines the amount of ink deposited
• Screen count, which affects the reproduction of graphic details
• Cell geometry, which influences ink release and transfer stability

In corrugated board printing, anilox rolls with higher volumes are generally used compared to those employed for coated substrates, in order to compensate for ink absorption on the liner layer of the corrugated board sheet and ensure uniform coverage of solid areas.

However, the anilox always works in combination with the printing plate and the printing pressure. If the pressure between the plate and the board is not correctly set, the printed dot can deform, generating defects such as poorly defined edges or excessive ink spread.

Ink management: a process that starts outside the machine

Good print quality begins before the flexo folder gluer. Ink management is a department-level process that includes preparation, monitoring and maintaining ink characteristics throughout production.

Key aspects include:

• Consistent mixing, to ensure color uniformity across batches and repeat orders
• Filtration, to protect plates and anilox rolls from impurities
• Recirculation and control, to keep the ink homogeneous over time

In this scenario, the flexo folder gluer does not replace the ink department, but it must be capable of operating consistently with parameters defined upstream, without introducing additional variables into the printing process.

Improper ink management can contribute to typical flexographic printing defects on corrugated board, such as color density variations, uneven solids or ghosting in repeated graphics.

Print stability and result control

In corrugated board printing, the variability of the substrate makes process stability essential. Constant pressure, uniform speeds and precise sheet transport are critical elements to achieve:

• Color consistency
• Sharp edges
• Repeatable performance over time

Corrugated board presents variable characteristics related to the flute type, the quality of the liner layer (the smooth outer sheet) and the absorption level of the material. These factors can influence ink behavior and print definition.

When the process is not stable, defects such as banding in solid areas, jagged edges in graphics or uneven solids may appear. A machine designed for stability allows operators to work within clearly defined process windows, reducing corrective interventions, waste and setup time, even during production start-up.

Quality and workflow: alignment between prepress and production

Print quality is increasingly the result of alignment between prepress and production. Plate characteristics, printing parameters and anilox selection must be consistent with the type of corrugated board and the desired graphic result.

When these parameters are clearly defined and shared, the flexo folder gluer can operate under more predictable conditions, reducing setup times and improving consistency across production runs.

In this context, the machine becomes a reliable tool that consistently executes the process choices defined by the company, enhancing operator expertise and established internal procedures.

Concrete benefits for the converting department

An approach based on process stability, control and consistency delivers measurable benefits:

• More consistent quality for the end customer

• Reduced startup waste

• Greater repeatability of results

• Fewer adjustments during production

• Higher productivity

Conclusion — Technology supporting the process

In modern converting, quality does not depend on a single factor, but on the machine’s ability to support a well-defined process.

The Royal VBDD by SIPACK has been designed with exactly this objective: to offer a solid, precise and flexible printing platform capable of delivering stability and repeatability over time.

Features such as:

• Direct drive motors on each axis, ensuring precise register control even at high production speeds
• Full-line vacuum transport, providing maximum sheet stability and improved print uniformity even on boards with variable characteristics
• Flexible and upgradeable configuration, allowing the machine to adapt to the evolving production needs of the box plant

make it possible to achieve reliable print results without locking customers into proprietary systems or rigid workflows.

With SIPACK, print quality becomes the result of a machine working in harmony with the company’s production process, transforming expertise and experience into a concrete competitive advantage.

In the corrugated cardboard converting industry, the adoption of increasingly advanced drive technologies has become a key factor in improving machine performance, process stability, and overall equipment effectiveness (OEE). Among these, independent motorization based on Direct Drive technology is gaining significant traction. This approach uses a dedicated motor for each axis or functional unit of the machine—typically a brushless motor—directly coupled to the driven component, without intermediate transmission elements such as belts or gears.

1. Independent Motorization and Direct Drive Explained

Direct Drive motorization is based on a simple yet highly effective concept: eliminating mechanical transmission components (belts, pulleys, gears) between the motor and the working axis, and connecting the motor directly to the moving part. This design minimizes power losses, friction, mechanical backlash, and wear-related components.

Direct Drive systems are usually implemented with brushless motors (servo or brushless DC) combined with advanced electronic control systems that precisely regulate speed and torque.

In corrugated box production machinery, this translates into extremely accurate control of all critical movements along the line—such as sheet handling, folding and gluing operations, and final conveying—resulting in higher operating speeds, improved synchronization, and consistently superior product quality.

2. Technical Advantages of Direct Drive in Corrugated Machinery

Reduced Noise and Vibration
The absence of mechanical transmission systems leads to a substantial reduction in noise and vibration during operation. Vibrations typical of belt- or gear-driven systems—often caused by backlash and mechanical compliance in the transmission elements—are virtually eliminated. As a result, the machine operates more quietly and remains more stable under load, an important advantage in high-speed production environments and multi-shift operations.

Lower Friction and Improved Energy Efficiency

With the motor directly coupled to the driven axis, there are no intermediate components dissipating energy through friction. This results in higher overall drive efficiency and improved energy performance, with potential reductions in electrical consumption and operating costs.

Higher Precision and Faster Dynamic Response

Electronic control of Direct Drive motors allows for extremely fast and accurate speed changes. This capability is particularly beneficial during fine positioning tasks, sheet alignment, and multi-axis synchronization, where system responsiveness directly impacts the final quality of the finished boxes.

Reduced Maintenance and Increased Reliability

Fewer moving mechanical parts mean reduced wear and significantly lower maintenance requirements. Belts and gears do not require replacement, lubrication, or periodic adjustment, simplifying scheduled maintenance and minimizing unplanned downtime—key factors in maximizing machine availability.

3. Why Direct Drive Matters in Corrugated Box Production

In corrugated production lines, productivity and reliability are critical performance indicators: every machine stoppage or quality deviation translates into tangible costs for the converter.

Direct Drive technology helps to:

• Improve process smoothness through precise synchronization of multiple independent motors, enhancing cutting, folding, and sheet transport accuracy.

• Reduce the risk of positioning errors, especially during short runs or frequent job and format changes.

• Enable higher levels of automation and electronic control, seamlessly integrated with modern digital supervision, monitoring, and diagnostic systems.

4. Conclusion: Tangible Value for the End Usern

For corrugated cardboard converters, Direct Drive technology and independent motorization represent a concrete lever for improving efficiency, quality, and competitiveness. Reducing mechanical friction and noise is not only an operational benefit—it leads directly to higher production accuracy, lower maintenance costs, and greater operational flexibility, particularly in environments characterized by frequent format changes and variable production requirements.

In the design of its corrugated cardboard machines, SIPACK integrates these principles to deliver robust and reliable solutions that maximize production efficiency and overall customer performance. Direct Drive is therefore not just a trend driven by market leaders, but a proven technology that delivers real, measurable advantages in everyday production environments.