Micro-flute (referred to as E, F, G, N, O and finer flute) is increasingly used in food, toys, small daily necessities, crafts, gifts, textiles, pharmaceuticals, daily chemical supplies, medical Outer packaging and buffer lining of products in industries such as equipment, electronics, digital products, communications, software, etc. and materials used for making advertising display racks and poster boards.
Due to the high compressive strength of fine corrugated cardboard, the use of recyclable corrugated base paper materials, and the printing effect like cardboard can be obtained. G-type and finer corrugated cardboard can also be directly used for fine offset printing. Mechanical strength but better elasticity and shock absorption performance than cardboard, and the light weight, lower transportation cost, lower application cost, more environmental protection and other excellent characteristics are being rapidly developed and applied in today's world. Especially in developed countries that pay special attention to environmental protection.
There are not many production lines for fine corrugated board in China. Some imported quick-change corrugated roll production lines are equipped with E and F corrugated rolls, such as the five-layer production line of BHS and the seven-layer production line of Agnati. The domestic production line has a small number of three-layer E corrugated cardboard production lines, most of which are E corrugated single-sided units and a small number of F corrugated single-sided units and a few modified G corrugated single-sided units. Since China joined the WTO, the economy has maintained a trend of continuous growth year after year, and foreign capital has continued to enter. China is becoming the world's processing center, which will inevitably promote greater development and technological progress in the domestic packaging industry. And in the future production and application market of fine corrugated board, we will definitely face a hearty cake.
The production of fine corrugated cardboard is a systematic project, from the design of corrugated shape, the structure and accuracy of Corrugated Rollers, the form of single-sided machine, the operating accuracy of all equipment of the production line, to the choice of paper, and the paper that matches the ideal speed during operation Tension control, temperature and humidity control, the preparation of glue paste and the control of the amount of glue and the quality control of paperboard, etc. have specific requirements that are different from conventional corrugated board such as A, C, B and so on.
1. The corrugated design of micro corrugation and the structure of Corrugated Roller
One of the characteristics of micro corrugations is the large number of flutes, the light weight of corrugated base paper and the low strength. Taking the number of flutes per 300 mm as an example: G type is 185 ± 12, N type is 200 ± 15, O type is 267, and B type is 50 ± 2. For a pair of corrugated rollers with the same diameter, the number of fine corrugated corrugations increased by 3 to 5 times compared to B-type corrugations. It can be seen that the tension during paper feeding and forming increases exponentially. Therefore, the design of the corrugated shape must ensure that the value of the corrugated angle of the corrugated shape is within the strength of the corrugated base paper. The choice of the arc of the corrugated top must make the entry resistance during the formation of the corrugated base paper smaller, smoother and smoother. At the same time, the corrugated angle must make the corrugated structure meet the sufficient rigidity and mechanical strength of the micro-corrugated cardboard. The corrugated surface of the micro-corrugated corrugated roller requires higher roughness requirements, and must be finely ground and polished to ensure high-speed forming of corrugated base paper with low grammage and low strength.
Basic corrugated parameters of micro corrugated:
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(Table 1: Basic corrugated parameters of micro corrugated)
For the production of fine corrugated corrugated rollers and related moving parts such as pressure rollers, rubber coating rollers and metering rollers, higher motion accuracy is required. Corrugated rollers and pressure rollers must also have more uniform and consistent forming and compound linear pressure to ensure Cardboard quality. Therefore, the wall thickness of the corrugated roller and the pressure roller must be uniform, and the accuracy of the cylindricity can be maintained after heating. At the same time, a reasonable design of the structure of the condensate drainage system is required to ensure that the corrugated roller does not stop due to water accumulation at the bottom To the temperature difference between the upper and lower to produce bending deformation. Corrugated rollers and pressure rollers must have more reasonable and high accuracy with consistent line pressure. The height of the micro corrugation is very low, and the wear of the corrugation height exceeding 0.1 mm will affect the quality of the product. For the corrugated roller of the micro corrugation, a more wear-resistant surface layer quality is required.
The flute form of the fine corrugated corrugated rollers, the vacuum external suction type and the positive pressure air cushion type are annular grooves, the vacuum internal suction type has annular grooves and herringbone semi-circular arc suction grooves. The flute of the corrugated roller with fine corrugation needs to be narrower to ensure that the finished product is not prone to degumming at the location of the flute. [next]
2. The form and glue system of the micro-corrugated single-sided machine
As can be seen from the corrugated structure of fine corrugation, the smaller corrugated top arc and the larger corrugated angle (partial V-shape) and a small indexing angle make the corrugated paper after forming at high speeds easily prone to corrugated rolls The centrifugal force generated by the operation to disengage the corrugated teeth of the corrugated roller affects the coating and compounding. A very reasonable positive and negative pressure structure design is required to ensure that the corrugated paper is reliably fixed on the corrugated teeth of the corrugated roller to complete the gluing and compounding, and the local degumming cannot be caused by the deformation of the wind groove caused by the wind pressure. Judging from the form of the single-sided machine, the positive-pressure air cushion makes the corrugated paper more stable on the corrugated rod, and the sealing performance of the structure makes it have a greater pressure leakage loss and heat loss than the vacuum suction and suction structures. Smaller and therefore the main structure of the current high-speed production line. From the perspective of the application of finished products of micro-corrugated cardboard, cardboard in the form of a herringbone semi-circular arc suction groove is better, which greatly reduces the risk of the air groove part falling exactly on the edge of the finished product.
The corrugated-top arc of small corrugation and the corrugated shape of dense cloth require a small and precise and stable amount of glue. The coating roller and metering roller (squeegee roller and metering roller) on the single-sided machine and gluing machine of the micro-corrugated production line must reach a motion accuracy of less than 0.02 mm, ensuring that the gap between the coating roller and the metering roller can be less than Outside the 0.08mm uniform glue gap, the surface of the glue roller needs to be designed to form a finer surface mesh with a thinner glue layer than that required by conventional corrugated cardboard.
3. Quality and process control of the base paper
The specifications and quality of micro-corrugated cardboard base paper lack more options than conventional corrugated cardboard base paper.
When 150 grams of ordinary corrugated base paper is passed around the C corrugated corrugated roof, it can smoothly transition and form on the corrugated arc of a radius of 1.25 mm. When the same base paper enters the G-type fine corrugated, the radius is 0.16 mm It is difficult to transition and shape the corrugated arc of the corrugated roof. Too small a bending radius makes the paper fiber break at the corrugated roof. Therefore, the fine corrugated paper must be of good strength, with a basic weight of less than 100 grams, and uniform air permeability, water absorption, and humidity.
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(Quality and process control of base paper)
In principle, a high-quality corrugated board production line is a balance of paper strength, tension, pressure, humidity, temperature and paste formulation at the ideal speed point.
Uneven strength and humidity of the base paper, unstable paste performance, fluctuations in the amount of glue and unbalanced preheating control and unbalanced heating will cause tension changes and break the balance at the ideal speed point.
Under the premise that the equipment conditions are met, fine corrugated production requires finer process control: the control of the quality index of the base paper, the control of the stable and accurate paper web tension, the control of the moisture of the base paper of the front and back processes, the control of the amount of glue, and the temperature. Control is the key to the production process of fine corrugated board. Among them, the entire line is suitable for precise tension adjustment, the angle of wrap of each preheated drying cylinder is adjusted in a timely manner, stable performance of high solid content starch paste, and the precise setting of the gap between the glue roller and the metering roller to ensure a small And the stable amount of glue, the precise temperature setting and adjustment of each heating point, etc. are the main control means. All the details of the entire corrugated board production line are adjusted and controlled in time according to the quality of the corrugated board, which can ensure the stable running speed of the entire production line, smooth transportation, and the production of high-quality fine corrugated board. [next]
Fourth, the transformation of micro corrugated single-sided machine
Since the widespread application of fine corrugated paper (especially G-type and finer corrugated paperboard that can be printed directly) has just begun, and there are not many large orders, there is a market demand for mass production on the corrugated board production line. development process. Therefore, a scheme with little investment and fast entry has made some color printing carton factories take the lead in emerging markets in recent years, that is, the use of new and old single-sided machines for micro-corrugation transformation. Suppliers of G-type micro-corrugated packaging, such as Melatonin and Siemens mobile phones, were all put into production by Changzhou Wujin Haili Rolling Company in 2001 and entered the new packaging market in China.
The characteristics of the fine corrugated corrugated type are that the corrugated type is more V-shaped and the radius of the corrugated top arc is smaller. After forming, due to the centrifugal force generated by the operation of the corrugated roller, it is easy to leave the corrugated teeth and affect the coating and compounding. The control of paper humidity, temperature, tension and running speed is extremely sensitive. At the same time, smaller corrugated-top arcs require correspondingly precisely controlled smaller amounts of glue. Therefore, the transformation work of the micro corrugated single-sided machine is carried out according to the above characteristics.
(1) Renovation project of micro corrugated single-sided machine
1. New corrugated roller:
(1) Corrugated design parameters (corrugated strength, wrap angle, corrugated flute arc, flute height, paper consumption rate, etc.)
(2) The structural design of the corrugated rollers is based on the different paper guide forms (vacuum negative pressure external suction type, vacuum negative pressure internal suction type or air cushion positive pressure type) of the corrugated paper after fixed forming. There are ring and herringbone).
(3) According to the rigidity of the roller body determined by the above structure of the corrugated roller and the different roller arrangement of each single-sided machine, design and calculate the median height of the passive corrugated roller.
2. Design, manufacture or modify different paper guide mechanisms (vacuum negative pressure external suction type, vacuum negative pressure internal suction type or air cushion positive pressure type):
(1), negative pressure hood or positive pressure sealed room.
(2) Set the appropriate air volume and pressure according to the specifications of the corrugated roller.
(3) Determine the number and position of paper guide copper sheets and tuyere according to the above form.
3. Glue system:
(1). The newly-made glue roller (paste roller) is designed to form a finer surface mesh with a thinner glue layer and achieve a circle runout accuracy of less than 0.02 mm.
(2) Newly-made metering rollers (uniform rubber roller, rubber scraper roller, quantitative roller) achieve a circle runout accuracy of less than 0.01 mm. Ensure that a glue gap of less than 0.08 mm can be achieved between the glue roller and the metering roller.
(3) Adjustable paste blocking device.
(4) Pneumatic device, which can quickly follow and disengage the glue application system. (Optional item)
4. According to the actual structure, installation location and surrounding environment of the single-sided machine, design the direction of the suction or supply duct, determine the location of the high-pressure fan, and manufacture the suction and supply duct system and high-pressure fan bracket.
5. According to the specifications of the corrugated roller and the set air volume and pressure, select the matching high-pressure fan and muffler.
6. Design electrical control system.
(2) Renovation procedure of the single-sided machine of fine corrugated board:
1. On-site surveying and verification of the relevant dimensions and technical parameters of the single-sided machine, corrugated rollers, rubber-coated rollers and metering rollers.
2. On-site design of pipeline trend and location of high-pressure fan.
3. Identify other renovation and repair items that must be added.
4. Choose a professional company for production (generally, the production time does not exceed the production cycle of the new corrugated roller).
5. On-site renovation engineering and installation and commissioning are carried out by professional engineering and technical personnel of a professional company (generally 2 days, some new repair items can be removed and sent to a professional company for repair at the same time), and operation training is also conducted.
According to the experience of Changzhou Wujin Haili Roll Manufacturing Company for the transformation of more than 100 single-sided machines over the years, under normal circumstances, the entire transformation process only requires a few hours of downtime during site surveying and mapping and 2 days of downtime during installation and commissioning. Production has little effect. If the supply and demand sides arrange carefully and cooperate well, the downtime can also be shortened. If conditions permit, the ideal is to send the whole machine to a professional company for simultaneous overhaul, so that you will get a brand new micro corrugated single-sided machine.
(3) Contents of other reconstruction and repair projects that must be added:
Because most of the single-sided machines that need to be modified are old ones, many parts have been worn, and need to be repaired, added and updated, it is possible to add other necessary renovation and repair items. (Checked by the engineering and technical personnel of a professional company)
1. Repair after the pressure roller is worn.
2. A pair of transmission gears on the lower corrugated roller and pressure roller needs to be newly manufactured after they are worn (there is no such project driven by gearbox and universal coupling)
3. Repair, replacement and addition of bearings, oil seals, sprockets, cylinders and other transmission, pneumatic, sealing and mechanical parts.
4. Restructuring, addition, replacement and repair of electrical control parts.
5. Overhaul costs. (Overhaul items include repair of all rollers, cleaning and restoration accuracy of all institutions, repainting of the whole machine, etc.)
(4) Transformation cost
If the overhaul is included, the cost for the fine corrugation of a single-sided machine with a 1600-format size is around 100,000.
(5) Transformation period
The project is officially confirmed, and it is usually delivered within 45 days.
In recent years, many customers in Shanghai, Jiangsu, Zhejiang, Shandong, Hubei, and Guangdong have been successfully transformed by Changzhou Wujin Haili Rolling Company, and have achieved very good results and benefits.
In China, the application market of micro corrugation is gradually emerging. Reconstruction of micro corrugated single-sided machine, the cost is economic, the technology is mature and reliable, the transformation period is short, the impact of production shutdown is small, users can enter the market development and application of new micro corrugated board products with minimum investment and fastest time, it is a good Way. But the micro corrugated single-sided machine renovation project involves a mature understanding of the principle characteristics of micro corrugated and very professional design and process technology. At the same time, the production of fine corrugated cardboard is a systematic project. It has specific requirements from the choice of paper, paper tension control during operation, temperature and humidity control, and cardboard quality control. Is a very critical element. Therefore, carton manufacturers should choose professional manufacturers to undertake renovation projects, fully consult with professional manufacturers on relevant reconstruction matters, and discuss the technical level and process strength of professional manufacturers and their product use by users, after-sale service network and service quality of professional manufacturers Wait for a comprehensive and careful detailed inspection and identification of the product's technical level, and choose carefully.
