Corporate decision makers should pay attention to the following issues when choosing medium and high-speed corrugated cardboard production lines.
First, do a good job of product market research is the basis for equipment selection
Corrugated carton products are a type of products that are large in and large out. Considering the increase in shipping costs and the timeliness of delivery, the market area of such products is doomed to not cover too much. The market scope is usually locked within 200 kilometers. Therefore, the decision-makers must conduct surveys and investigations on the major specifications and defects of major potential customers' products, and be aware of them, so as to provide the basis for the next decision.
In addition, we must also understand the equipment status, management status, and customer status of the surrounding competitors so as to provide the basis for the next step in the development of marketing measures.
Second, consider the overall coordination of the corrugated board production line
For the medium and high-speed corrugated paperboard production line, the matching principle is to take into account the level of automation of each single machine, and more attention should be paid to the overall matching and coordination of the corrugated board production line. Since the high-speed production line is chosen, the entire line with a high degree of automation should be selected to match the configuration.
For example, it needs to be equipped with an automatic splicer (according to the entire line speed, a splicer that selects the proper speed, the number of which is determined according to its own economic situation), and a positive-pressure card singe-type single-faced corrugating machine (with convenient roll change, smooth operation, and speed (Fast), production management system, internal expansion chuck (for safety needs to select more brakes), automatic thin knife slitter (in order to facilitate a quick change, need to be equipped with 2), slitting machine Equipped with three kinds of pressure wheel (convex concave, convex concave, convex flat), spiral cross cutting machine, automatic glue system, coating machine (pressure regulating pressure bar instead of pressure roller), double The number of hotplates on the surface must be matched with the speed (spring-type hot platens for the drying section, of course, the quality of the condensate traps must be considered).
Third, focus on selecting the key components of the key
Several important technical points of corrugating roller
For high-speed machines, the diameter of a single-sided machine is usually not less than 320mm, otherwise speed is difficult to mention. In general, the corrugating roller diameter is selected to be 375mm or more.
Nowadays, the most commonly used single-sided machines on the market are mostly unshielded fork vacuum suction single-sided machines or positive pressure card-type single-sided machines. In actual operation, it is necessary to control the matching pressure (with clearance) and parallel of the corrugating roller. Degrees, the temperature of the surface, and the choice of the appropriate height.
Of course, the control of the temperature of the corrugating roller surface (usually 160-180° C.) is closely related to the saturated vapor pressure and the discharge of condensed water. We know that after saturated steam passes through the corrugating roll, it releases latent heat and condenses into condensed water. Since the thermal conductivity of condensed water is low, if it is not collected smoothly and accumulates in the roll, it will greatly increase the thermal resistance of the roll and cause roll The surface temperature of the drum drops and it cannot work at normal speed.
When the condensed water in the roller accumulates to a certain extent, the outlet of the drain pipe is blocked. Since the saturated vapor pressure in the roller is greater than the pressure at the drain pipe end, the pressure difference at both ends continuously discharges the condensed water, so the condensed water discharge pipe The port must be mounted downwards and the end should be as close as possible to the inner wall of the lower part of the roller body in order to maximally eliminate condensation. Of course, the nozzle cannot contact the inner wall, because the roller is rotating, and the condensate drain pipe and the steam rotary joint are fixed, otherwise noise may occur and the drain pipe may be damaged. The fixed suction tube is usually made at an angle of 45° to the bottom surface.
Because the corrugating roller is in the meshing process, pressurizing both ends of the upper corrugating roller will cause it to have a certain deflection, so that the gap in the middle part of the corrugating roller will increase. For this reason, the center diameter of the corrugating roller must be slightly larger than the two ends when it is manufactured. This difference is medium high. According to the industry standard QB/T2498--2000 “Corrugated Cardboard Production Line”, the high corrugating roll height on the machine is usually 4 times the roll deflection.
Preheat cylinder
Preheat cylinder cylinder diameter can not be less than 900mm, must have the biggest wrap angle adjustment ability, to adjust the humidity of the base paper to ensure the formation of cardboard.
Applicator touch bar
We know that traditional glue applicators use gravity roller gluing. If a small amount of cardboard is produced for a long time, the middle part of the upper paste roller and the gravure roller will be seriously worn. When large-format cardboard is produced, wear occurs in the middle. The middle part will not be good glue, causing cardboard degumming, blistering and poor adhesion and other issues, and the two sides of the place where there is no wear due to pressure, but also will change the corrugated board shape to varying degrees of deformation, glue Too much volume makes the cardboard soft and its strength decreases.
When changing the material of the paper (transformation between high gram paper and low gram paper) and changing the corrugated shape, it is necessary to adjust the gap of the pressure paper gravity roller. This is an inconvenient task. If the adjustment is not good, it will flatten the paperboard corrugated or cannot be glued, resulting in the cardboard being scrapped. If the operator wants to save time, no matter what type of rake type uses a minimum clearance, the strength of the cardboard will cause great damage. For example, the height of the B-tile is 2.7mm, and the gap between the rubber roll and the gravure roller is 2.6mm according to the normal standard, so that the paste can be uniformly applied. That is to say, the corrugated cardboard must be flattened according to the normal adjustment. Mm, but the squashing of the cardboard will use a lot of glue, of course, squashing and gluing a lot of cardboard in the hardness and compressive strength will drop a lot.
The pressurizing stick of the coating machine is installed on the coating machine and is used to replace the traditional gravity roller, and is composed of a set of elastic compression pieces with pressure equalization. The contact pressure bar is formed by connecting a plurality of wear-resistant curved sheet plates and a spring. The elastic force of the spring always allows the arc-shaped sheet to evenly fit on the upper paste roller, even if the upper paste roller wears and recesses, the spring sheet plate Also with the depression, the corrugated paper is always evenly attached to the upper paste roller, so that the corrugated paper is uniformly pasteted.
The pressure contact bar is designed to have the same curvature as the top roller to ensure stable pressure, uniform paste, and easy control of the amount of glue. There is an independently controlled elastic device on the tablet, which automatically adjusts the irregular beat, avoids flattening of the shape and ensures the strength of the cardboard.
Currently on the market, the elastic devices for tableting are mechanical springs and automatic pressure regulators.
Ordinary spring-type contact pressure rods Due to the non-adjustable spring pressure, the spring elasticity is prone to fatigue, resulting in a series of problems. For example, the spring pressure assembly will flatten the corrugated lining, which will affect the pressure resistance and sizing too much. As a result, the vehicle speed will become slower and the cardboard will become softer. When the spring pressure is small, the sizing will not be uniform, and the cardboard will be degummed and foamed.
The pneumatic pressure regulating system of the pressure regulating pressure bar adopts a stable and reliable cylinder type push rod design, and is equipped with high-quality precision machining and imported wear resistant pneumatic materials to ensure long-term stable and reliable operation of the touch bar, and the device does not need to be used. Adjust the height to feel free to use a variety of paper materials. There is no need to adjust the gap when the material of the paper is thin and the shape of the die is changed. In this way, when the corrugating medium is glued into the glue applicator, the height of the corrugated paper and the height of the corrugation after the upper paste is dispensed from the coater are basically the same, and the occurrence of falling or flattening of the tip of the shredder is avoided, the shape of the crepe is maintained, and the glue is applied. Evenly, it saves a lot of corn starch glue. The final cardboard is close to the ideal standard, so that the compressive strength is high, and the process requirements and the thickness and strength of the cardboard are ensured.
Double-sided machine drying section hot plate number and hot platen matters needing attention
The number of hot plates in the drying section must be matched with the high-speed production line. Otherwise, the glued cardboard will not be fully dried, and the adhesive will be poorly gelatinized. If the speed is too high, a large amount of cardboard will be degummed too softly. Usually, the number of hot plates cannot be reduced. In 18 blocks.
The double-sided machine hot plate is installed in the hot part of the drying section, which is a new product used to replace the traditional gravure roller and make the corrugated board heat-transfer and dry quickly in the hot plate section. The hot pressing plate of the drying section is made of special stainless steel sheets of wear-resistant material and special springs. Each hot baking plate is divided into a group. Each group of hot pressing plates can automatically select and move according to different temperatures and different temperatures. Easy to operate.
We know that any material has the characteristics of thermal expansion and contraction. When the corrugated board is dried by a hot plate, it will take a lot of heat, so that the temperature of the bottom of the hot plate and the surface are inconsistent. The above temperature is low, and the hot bake plate is concavely deformed, especially in the first to fifth blocks. The faster the speed, the more heat taken away and the greater the deformation. In addition, the traditional gravity roller is a straight line that is line contact and does not bend as the hot plate deforms. In this way, the middle part is not pressed, and the two sides are too heavy, resulting in degumming, blistering, and poor adhesion of the cardboard. Of course, the corrugated shapes on both sides are flattened. In addition, its heat transfer efficiency is low, if the speed is too fast, the cardboard will degummed due to insufficient heat, resulting in poor adhesion. Due to the fact that the roller press shaft is installed in a decentralized manner, the weight is not easy to adjust, and it is easy to flatten and collapse the corrugated board shape, and the produced cardboard will also be uneven, especially when the single corrugated board and the double corrugated cardboard are changed. Adjustment.
The hot plate contact plate is specially designed for the above problems. Its working principle is the same as the spring type contact pressure bar on the coating machine. It is assembled by springs and grouped wear-resistant stainless steel plates. The stable pressure required for the hot plate is ensured at all times so that the corrugated core paper is completely attached to the hot bake plate, so that every place of the corrugated cardboard can be heated evenly. Regardless of whether the hot plate is deformed or bulged, the elastically balanced spring always sticks a piece of platen to the hot plate as the hot plate dents or bulges, even if a poor quality core paper is not used. It will flatten the crucible shape and have high heat efficiency, fast gelatinization speed, no degumming, no foaming, and good laminating of the paperboard. The paperboard produced is both flat and hard and has good compressive strength. According to the test, the heat transfer efficiency of the hot plate after modification of the hot platen is much higher than that of the traditional roller shaft type. Of course, the speed of the cardboard plate after entering the drying plate is greatly increased. In addition, each hot plate is divided into a set of hot platens that can individually control the lift. Each hot plate can be individually controlled. According to different speeds, different temperatures freely choose to go up and down. The lift can be controlled automatically (PLC control) or manually, making it very easy and convenient to use.
Several equipment configurations to reduce waste of raw paper
In the previously-manufactured medium and low-speed production lines, the chuck of the original paper holder is generally a hexagonal cone chuck. During use, the paper paper tube and the inner paper edge are broken, making the paper tail difficult to use, resulting in waste of raw materials. Most modern high-speed lines use internally-incremented chucks. The structure is simple, and there is no need for power assistance. The chuck ribs shrink or loosen as the paper frame is moved horizontally. They automatically expand and expand in the paper tube to fix the base paper. The utility model solves the disadvantages of the taper collet breaking the tail paper and improves the utilization of the paper tail.
For today's high-speed production lines, equipped with automatic performance and stable speed is also an important equipment to solve paper waste. Although the cost of investing in the production equipment has just been increased, the automatic splicer can realize zero-end paper-making, which can save a lot of original paper in one production shift. Usually, the length of the manual splicing joint is about 3 to 5 meters, and the joint of the automatic splicing machine is generally only 6 to 8 cm. This can reduce the consumption of paper, save fuel power, and increase production efficiency.
The installation of constant tension control system is a key device to solve a series of quality problems of cardboard. Because the constant tension control system can detect the tightness of the web at any time, and adjust the brake force of the original paper brake (now need to be equipped with a multi-point brake) in real time according to the change, a control loop for detecting→feedback→braking is formed to keep the paper web Keep running under the set tension.
For a high-speed corrugated paperboard production line, the provision of a production management system is an important measure to solve paper waste and save fuel power, and an important part of improving production efficiency, so it should be considered before selection.
