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The function, shape and working principle of the paper guide board In the manufacturing process of the corrugated board, the corrugated medium paper is rolled into a wavy shape by entering the upper and lower corrugating rolls in the single-sided machine. The function of the paper guide board is to peel the corrugating medium paper which has been rolled into a corrugated shape from the upper corrugating roll and attach it to the tooth surface of the lower corrugating roll without being thrown off by the centrifugal force of the corrugating roll so that the glue can be applied. When the roller applies adhesive to the dome, the position of the corrugated cardboard is guided; then, the adhesive-coated corrugated paper is guided between the lower corrugating roller and the pressure roller to ensure that it is located in the semi-annular space formed by the paper guide and the lower corrugating roller. In the cavity, it does not stretch freely and is properly bonded with the backing paper under the action of the pressure roller press mechanism. It can be seen that the paper guides serve to guide, limit and facilitate the bonding.
The basic outline of the paper guide is shown in Figure 1 (abbreviated). It is a half-moon plate-like structure that is concentric with the lower corrugating roll and is fixed by a holding device at a certain distance, and depends on the lower corrugating roll. The upper end is inserted into the groove of the corrugating roller so as to prevent the formed corrugated cardboard from being rolled up with the upper corrugating roller, and the waist is embedded in the groove of the sizing roller so that the sizing roller can smoothly apply the adhesive. The number of paper guides is equal to the number of grooves in the upper corrugating roll and the sizing roll. According to different types of rakes, the spacing of the paper guides is not the same, usually 75 to 100 mm for A-type crucibles, 50 mm for B-type crucibles, 65 mm for C-type crucibles, and 35 mm for E-type crucibles.
The material of the paper guide and the basic size parameters The guide material selection principle is soft and wear-resistant. Because the paper guide is embedded in the groove of the upper corrugating roller and the sizing roller, once the single-faced machine is started, once the machine is running abnormally, it will cause the paper guide plate to collide with the groove of the upper corrugating roller or the sizing roller. The above-mentioned two-roll groove is not damaged, and the hardness of the paper guide board is required to be low; when the machine is running, the paper guide board and the corrugated paper are in contact with each other, so the paper guide board should be wear-resistant. The paper guide is usually made of phosphor bronze material.
Since the paper guide plate is set in the groove of the sizing roller, the sizing roller will leave a blank groove line without adhesive on the corrugated paper when coating the adhesive. We call this “dry streaks. ". In order to avoid “dry stripe†being too wide and reducing the bonding quality and aesthetics of corrugated cardboard, the thickness of the paper guide board is required to be thinner, but if it is too thin, the paper guide board may be deformed to affect the quality of the corrugated board. In general, the thickness of the paper guide is 1.5 to 2.0 mm, which is about 1 mm narrower than the upper corrugation roll groove and the sizing roll groove.
The paper guide needs to be made into a half-moon shape formed by R1, R2, and R33 arcs, and let R1> R2> R3, where R2 is the radius of the lower corrugating roller concentric circle. In theory, the paper guide should be concentric with the lower corrugating roller, but in order to facilitate the smooth entry of the corrugated paper into the annular cavity, R1>R2 should be made. At the same time, when the corrugated paper is attached to the lower corrugating roller, it is also subjected to the squeegee roller to coat the dome. To prevent the sizing roller from coming into contact with the lower corrugating roller, the part where the two rollers join the core line is made concave (R3). ). The corrugating medium of the shaped corrugated paper is projected outward from the position of R3 due to the centrifugal force. After contact with the sizing roll, the corrugated ridges are joined together by R2 and R1. Only in this way can a qualified corrugated stencil be obtained. If the inner radiuses R1, R2, and R3 of the paper guides are equal, it is likely that the corrugations will be confused.
The working surface of the paper guide has a circular arc R2 = a lower corrugating roll radius r + a corrugated medium paper thickness h + a gap δ between the corrugated medium paper and the lower corrugating roll. The arc of R3 is approximately 1 mm below the R2 arc. The R3 value of Type B stencils is smaller than that of Type A stencils. For E-type corrugations, because of the small height, if there is also an R3 arc, there is a danger of crushing the corrugated shape. Therefore, the guide plate of the E-type single-sided machine is not R3.
There should be a suitable gap between the circular arc of the paper guide face R2 and the outer circle of the lower corrugated roller. If the gap is too large, the corrugated paper will bounce on the surface of the corrugating roller, affecting the correct coating of the adhesive on the corrugated paper, resulting in poor adhesion, inaccurate shape, or high and low defects; the gap is too small, the corrugated paper is not easy to pass, and the paper guide is not easy to pass. The coverage increases the width of the "dry streak" and then affects the bonding quality. In general, the gap between the paper guide arc and the lower corrugating roll is A type 0.75 mm, B type 0.4 mm, C type 0.45 mm, and E type 0.2 to 0.3 mm.
The installation, adjustment and maintenance of the paper guide The correct position of the paper guide installation affects the service life of the paper guide and the quality of the corrugated board to a large extent. Before installation, check whether the paper guides are deformed, be sure to keep the clamping surfaces on both sides straight, and use the molds to properly fix the paper guides on the holding device. At the beginning of installation, the upper end of the assembled paper guide is first embedded in a corrugating roller, and the clamping device is mounted on the frame to keep the guide plate stable and perpendicular to the connecting lines of the upper and lower corrugating rollers and the pressure roller. And it can be adjusted along the vertical direction of the three rollers. Second, adjusting the position of the paper guide in the groove requires that the center line of the upper corrugation roll groove and the sizing roll groove and the center line of the paper guide board be accurately aligned so as not to be squeezed in the production process due to the guide paper skew.æª æª åŠ é€Ÿ åŠ é€Ÿ æª æª æª æª æª æª åŠ é€Ÿ åŠ é€Ÿ æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª æª. Then adjust the gap and relative position of the paper guide and the lower corrugating roller so that the arcuate surface of the paper guide and the lower corrugating roller maintain the correct clearance. Finally, start the machine, adjust the distance between the rollers, and carefully observe the correct installation position of the paper guide, and confirm that there is no mistake and fix it.
It should be noted that the installation and adjustment of the paper guide must be carried out after the temperature of the corrugating roll has risen, otherwise the upper corrugating roll will be thermally expanded and the groove size will change, which may cause deformation or wear of the paper guide. Currently, there are many types of single-sided machines on the market, and the structure and clamping manner of the holding device of the paper guide board are not the same. However, most factories all use the formwork to correctly install the paper guide on the clamping device so that Replace quickly when cleaning or adjusting.
When the paper guides are working, adhesives are often adhered to both sides. These adhesives continuously accumulate and harden, which directly affects the quality of the paperboard. Therefore, timely removal of accumulated adhesive is an important step in maintaining the paper guide.
Defects in the paper guide and improvement The life of the paper guide is generally 300,000 to 700,000 meters long. At present, the market price of paper guides is about RMB 25/piece, which consumes a considerable amount of time, and it takes a lot of man-hours to replace and adjust. In addition, the paper guides produce dry streaks due to their own thickness during work. Currently at home and abroad are actively developing single-sided machines without paper guides, such as vacuum adsorption, suction vacuum cover type and pressurized air-cushion type single-sided machine to improve production efficiency and eliminate quality defects. (Xiamen Packaging & Printing Group Co., Ltd. Guo Xubin)
Application of Paper Guide in Corrugated Cardboard Production
At present, the packaging industry occupies an increasingly important position in the national economies of all countries in the world. Countries are competing to develop more advanced, reasonable, and efficient equipment to meet the growing market demand, including the corrugated cardboard line tooling. The rapid development. However, most of the companies in China, especially small and medium-sized corrugated cartons production plants, still use paper guides as one of the basic components of the central equipment. The paper guide directly relates to the corrugated board production quality and production efficiency. This paper focuses on the role, parameter selection, and installation and maintenance of the paper guide in the production of corrugated cardboard.