Prepress Machine

The 2023 labelexpo Asia show we participated in in December was a complete success.

I am very happy that many customers from Russia, the Middle East, and Southeast Asia are very interested in our printing machines, slitting machines, and die cutting machines.

There are also customers who place orders directly after discuss with us about machine details in exhibition. Thank you for all the customer trust and support. We will continue to update, bring better machines and services to our customers.

The process of making paper has evolved significantly over the years, integrating modern technologies to improve efficiency and quality. One such innovation is the use of Flexo printing machines, which play a crucial role in enhancing paper printing for various applications, especially in packaging and labeling.

Q1: What is the basic process of making paper?

Making paper involves several essential steps, starting with the raw material, usually wood or recycled paper. The process begins with pulping, where the fibers are broken down into a slurry. This slurry is then spread onto large screens, drained to remove excess water, and pressed to form a smooth sheet. After pressing, the paper is dried, often using heated rollers. Finally, the paper is cut into desired sizes and is ready for use.

Q2: How has technology, such as Flexo Printing Machines, improved the paper production process?

Flexo printing machines have revolutionized the way paper is printed, especially for packaging and label production. These machines use flexible relief plates to apply ink to the surface of the paper, which ensures high-quality prints, even on rough or uneven surfaces. The integration of Flexo printing in paper manufacturing allows for faster production speeds, cost-effectiveness, and the ability to print complex designs, making it highly valuable for modern paper-based products like cartons and flexible packaging.

Q3: Why is the drying stage of paper-making important?

The drying stage is critical because it removes moisture from the paper, allowing it to gain the necessary strength and durability. This process also influences the smoothness and texture of the final product. In some paper mills, advanced dryers, including infrared or heated roller systems, ensure that the paper dries evenly, contributing to the quality of the end product.

Q4: How does sustainability factor into modern paper-making?

Sustainability plays a vital role in modern paper production. Many paper mills now prioritize recycling and use recycled paper as raw material, which reduces the need for virgin wood pulp and minimizes environmental impact. Additionally, there has been significant advancement in eco-friendly manufacturing technologies, such as energy-efficient machines and water conservation methods, ensuring that the paper-making process is more sustainable than ever.

Q5: What types of paper are produced using Flexo printing technology?

Flexo printing is particularly suited for producing various types of packaging paper, such as corrugated cardboard, paper bags, and flexible packaging materials. It is also commonly used for printing on tissue paper, labels, and even wallpaper. Its ability to handle large volumes of print runs with high consistency and clarity makes it a preferred choice for manufacturers aiming to deliver high-quality printed paper products.

This approach to paper production demonstrates how technology like Flexo printing machines is advancing the industry, improving efficiency, and opening up new possibilities for high-quality, sustainable paper products.

Film slitting rewinding machines are essential in the plastic film processing industry. They slit wide plastic film rolls as per specific demands and rewind them into standard small rolls for various applications.

I. Basic Structure and Components
Unwinding Unit
The unwinding unit, the starting part, holds and releases the wide film roll. It has an adjustable tension control system. For example, magnetic powder brakes or servo motors control the unwinding resistance. The unwinding shaft, like an air expansion shaft, eases roll loading and unloading.
Cutting Unit
The core cutting unit uses tools like round and straight knives. Round knives suit thin, flexible films, cutting fast with smooth edges. Straight knives are for thicker or special films. It has a tool adjustment device to set position, angle, and pressure according to film thickness and material for precise cutting.
Rewinding Unit
The rewinding unit rewinds slit films. It has winding shafts (central or surface types), pressure rollers, and a tension control system. The central shaft is motor-driven for high-tension films; the surface shaft uses friction for thinner films. Pressure rollers ensure tight winding, and the tension system keeps film tension stable for good roll quality.

II. Working Process
Roll Installation and Preparation
First, install the film roll on the unwinding shaft and fix it. Then, check components, set the cutting width, and adjust tension parameters on the operation panel.
Unwinding and Cutting
After starting, the unwinding unit releases the roll. The film moves forward under tension and enters the cutting unit. The tools cut it into narrow strips according to the set width.
Rewinding and Finishing
The slit strips enter the rewinding unit. Pressure rollers press them onto the winding shaft. The tension system monitors and adjusts. As the roll diameter grows, parameters adjust for quality winding. When set, the equipment stops, and the rolls are ready for packaging.

III. Application Fields
Packaging Industry
In packaging, films from these machines are used widely. For food packaging, like wrap films and bags, and industrial product packaging, they provide suitable films for protection and appearance.
Electronics Industry
The electronics industry demands high precision. These machines slit optical, insulating films, etc., into tiny sizes for components. For LCDs, they cut polarizing films precisely, and for circuit boards, they get the right films for insulation.
Agriculture
In agriculture, films from Film Slitting Rewinding  machines cover greenhouse sheds and are used as mulch films. They are slit to fit different greenhouse and crop needs, enhancing production efficiency and crop protection.

Slitting machines play a vital role in the field of material processing. They can precisely cut wide rolls of materials into predetermined widths, lengths or shapes, and are widely used in the processing of various materials such as paper, plastic films, and metal foils. Understanding their working principle is of key significance for optimizing the slitting process, improving production efficiency and ensuring product quality.

I. Principle of the Unwinding System
Installation and Fixation of Rolls
The unwinding system of the slitting machine first needs to correctly install the roll to be slit on the unwinding shaft. Usually, expansion-type or chuck-type installation methods are adopted to ensure that the roll will not become loose or displaced during high-speed rotation. For example, the expansion-type unwinding shaft expands the shaft core through internal air pressure or mechanical structure to tightly clamp the inner core of the roll, providing a stable foundation for the subsequent unwinding process.
Tension Control Mechanism
To ensure that the roll is transported smoothly and evenly during the unwinding process, the unwinding system is equipped with a tension control system. This system uses tension sensors to monitor the tension of the roll in real time and compares it with the set value. If the tension is too high, it will cause the roll to stretch, deform or even break; if the tension is too low, problems such as slack and wrinkles may occur during the unwinding process. For example, when the tension sensor detects that the tension is higher than the set value, the control system will automatically adjust the rotation speed of the unwinding motor to slow it down, thereby reducing the tension of the roll; conversely, if the tension is lower than the set value, the motor speed will be increased to increase the tension.

II. Principle of the Cutting System
Types and Selection of Cutters
The cutting system of the slitting machine uses various types of cutters, with round knives and straight knives being common. Round knives are suitable for cutting thinner materials with certain flexibility, such as plastic films and paper. They can generate continuous cutting force through high-speed rotation, and the cutting edges are relatively smooth. Straight knives are more suitable for cutting thicker and harder materials, such as metal foils. The material of the cutters is also crucial. High-quality cutter materials have high hardness, wear resistance and good toughness. For example, cutters made of cemented carbide can maintain sharpness during long-term cutting, reducing the frequency of cutter replacement and improving production efficiency.
Cutting Actions and Adjustments
During the cutting process, the cutters operate according to the set parameters. For round knives, their rotation speed, the contact angle with the roll, and the clearance between the upper and lower round knives need to be precisely adjusted. For example, when cutting thin plastic films, appropriately reducing the rotation speed and contact pressure of the round knives can prevent the films from being stretched or having burrs during the cutting process. Meanwhile, the clearance between the upper and lower round knives needs to be adjusted according to the thickness of the films. If the clearance is too large, the cutting cannot be completed; if it is too small, it will increase cutter wear and cutting resistance. For straight knives, the stroke and speed of their up and down movements as well as their relative position to the roll also need to be precisely controlled to ensure the accuracy and stability of the cutting.

III. Principle of the Rewinding System
Rewinding Methods and Structures
The materials after slitting are collected and organized by the rewinding system. There are central rewinding and surface rewinding methods. Central rewinding involves winding the slit materials around the core shaft of the rewinding roll. The core shaft is driven to rotate by a motor. This method is suitable for situations where higher rewinding tension is required and the materials are relatively thick. Surface rewinding relies on the friction between the rewinding roll and the materials to drive the materials to be rewound. It is suitable for thinner materials with relatively low tension requirements. The rewinding system also includes auxiliary structures such as pressure rollers. The role of the pressure rollers is to closely attach the slit materials to the rewinding roll to prevent problems such as loose winding or air entrainment.
Rewinding Tension and Speed Control
The rewinding system also needs to precisely control the tension and speed. The rewinding tension should match the unwinding tension and remain stable during the rewinding process. If the rewinding tension is too large, the rewound materials will be wound too tightly, resulting in internal stress and affecting the quality of the materials; if the tension is too small, the materials will be wound loosely, which is not conducive to subsequent storage and transportation. For example, at the beginning of the rewinding process, since the diameter of the material roll is small, the rewinding tension can be set appropriately low; as the rewinding process progresses and the diameter of the material roll gradually increases, the rewinding tension needs to be adjusted accordingly to ensure the winding quality of the materials throughout the rewinding process. The rewinding speed also needs to be reasonably controlled according to the overall production efficiency of the slitting machine and the characteristics of the materials. Excessive rewinding speed may cause problems such as material offset and wrinkles during the rewinding process.
 

The label rotary die cutting machine plays a crucial role in the label printing and processing industry. Its cutting effect is directly related to the quality of labels and production efficiency. Numerous factors can have an impact on its cutting process. A deep understanding of these factors is of great significance for optimizing the die cutting process, improving product quality, and reducing production costs.

Blade-related Factors
Blade Material and Hardness
The material of the blade determines its key properties such as wear resistance, toughness, and sharpness. For example, blades made of high-quality high-speed steel have high hardness and good wear resistance, enabling them to maintain a sharp cutting edge during the long die cutting process, thus ensuring the neatness and smoothness of the cutting edges. Blades with insufficient hardness are prone to edge wear and dulling when cutting relatively hard label materials, resulting in rough cutting surfaces and even the inability to complete the cutting task smoothly.
Blade Edge Shape and Angle
Different edge shapes and angles are suitable for different types of label materials and die cutting requirements. For thin paper labels, a sharp edge with a small angle can achieve precise and rapid cutting and reduce the pulling of paper fibers. For some plastic labels with a certain thickness or toughness, special-shaped edges, such as wavy edges, may be required to distribute the cutting pressure and prevent the materials from deforming or tearing during the cutting process. Incorrect selection of the edge shape or angle will lead to uneven distribution of cutting force and cause problems with the quality of label cutting.

Die Cutting Pressure Factors
Precise Setting of Pressure Magnitude
Appropriate die cutting pressure is one of the core factors to ensure a good cutting effect. If the pressure is too low, the blade cannot completely cut through the label materials, resulting in phenomena such as incomplete cutting and continuous cutting, which will affect the separation and use of the labels. For example, when cutting multi-layer composite label materials, if the pressure is insufficient, the layers of materials may not be completely separated. On the contrary, excessive pressure will cause excessive wear on the blades and equipment and may also lead to the crushing and deformation of the label materials. Especially for some labels with soft textures or special coatings on the surface, such as thermal labels, excessive pressure will damage their thermal coatings and affect the functional characteristics of the labels.
Uniformity of Pressure
The uniform distribution of die cutting pressure across the entire die cutting area is also of vital importance. If the pressure is uneven, the edges of the labels after cutting will show different degrees of quality differences, such as some edges being smooth and some having burrs or serrations. This may be caused by factors such as poor surface flatness of the die cutting rollers, failure of the pressure adjustment device, or uneven thickness of the label materials. For example, when the die cutting rollers have local wear after long-term use, the pressure in this area will be inconsistent with that in other areas, thus affecting the cutting effect.

Label Material Property Factors
Material Thickness and Hardness
The thickness and hardness of label materials have a significant impact on the die cutting process. Thicker or harder materials require greater die cutting force to complete the cutting. For example, thick cardboard labels require higher pressure and sharper blades compared to thin paper labels. Moreover, the uneven hardness of materials, such as some label materials containing fiber impurities or local hardening, will increase the difficulty of die cutting, easily lead to increased blade wear, or unstable cutting quality, and may result in local incomplete cutting or uneven cutting surfaces.
Material Flexibility and Elasticity
Label materials with high flexibility and elasticity, such as some rubber or stretchable plastic labels, are prone to rebound during die cutting. This requires that the blade and pressure settings of the  Label Rotary die cutting machine can adapt to this characteristic. Otherwise, the edges of the cut labels may not remain flat and may curl or deform. For example, when cutting elastic rubber labels, if the cutting speed and pressure cannot be reasonably controlled, the labels will rebound quickly after the blade leaves, resulting in uneven cutting edges and affecting the appearance and pasting effect of the labels.

Equipment Mechanical Precision Factors
Concentricity and Cylindricity of Die Cutting Rollers
The concentricity and cylindricity of die cutting rollers are directly related to the uniformity and stability of die cutting pressure. If the concentricity of the die cutting rollers is poor, radial runout will occur during the rotation process, causing the die cutting pressure to change periodically, resulting in regularly uneven cutting edges of the labels. The cylindricity error will make the contact area between the die cutting rollers and the label materials uneven, causing local excessive or insufficient pressure and affecting the cutting quality. For example, when the die cutting rollers have a large concentricity deviation due to manufacturing or installation precision problems, the edges of the cut labels will have obvious wavy undulations.
Precision and Stability of the Transmission System
The precision and stability of the equipment's transmission system also have an important impact on the die cutting effect. The transmission system includes components such as motors, gears, and chains. If the transmission precision is insufficient, such as excessive gear meshing clearance and chain slack, it will lead to unstable rotation speed of the die cutting rollers or instantaneous pauses, making the relative movement between the blades and the label materials discontinuous, thus producing scratches, faults, and other defects on the cutting surfaces of the labels. Moreover, unstable transmission will also exacerbate the wear of blades and other components of the equipment, reducing the service life and reliability of the equipment.