Achievements of small-scale transformation of carton enterprises (I)
nowadays PCU is more antioxidant than UHMWPE. A considerable number of industries have experienced oversupply, and many products are gradually entering the era of meager profits. As a supporting product of other industries, it is unrealistic to obtain higher profits under such circumstances, and even reasonable profits are difficult to be guaranteed. Coupled with the high prices of raw materials, the imperfect production equipment and the limitations of the technical level of operating workers, many carton enterprises are struggling on the edge of loss. Some enterprises are even difficult to maintain and are ready to close down. Is the carton industry really so pessimistic? no The development of the carton industry lies at our own feet. Only through continuous innovation and reform can we inject a steady stream of vitality into the enterprise
the author was engaged in packaging work in the 1960s. At the beginning, due to the backward production equipment and process, he made some minor changes in the unit. In the 1980s, Shanghai packaging and decoration company, the superior company of Shanghai packaging industry, established a technical service department. The author was a member of the technical service department at that time. Due to the needs of work, he often provided technical services and technical support to carton factories everywhere. So far, more than 100 carton factories have left the footprints of the author. Due to many problems encountered and different solutions, I have accumulated some experience in production operation, equipment transformation and equipment maintenance. Today, I use this exchange platform to communicate with my peers
I. Changes in product quality after the position of the paper guide roller of the single-sided machine changes
in the production process of single-sided corrugated board, we all know that a pair of corrugated rollers press the corrugated original paper into a corrugated shape, and then the pressure rollers cooperate to bond the corrugated paper coated with adhesive with another layer of paper to form a single-sided corrugated board. However, when the corrugating roll and the pressure roll are running at high speed, the raw adhesive should be gelatinized, bonded and cured in a very short time. As the heat exchange time is very short, if the production speed is 100 m/min, the contact time of the two layers of paperboard at the pressure point is 0.6 seconds, and the production speed is 200 m/min, the contact time of the two layers of paperboard at the pressure point is only 0.3 seconds. If the surface temperature is low or the pressure is not adjusted in place, some quality problems will often occur, such as poor adhesion. We found that if some parts in this production process are modified, the quality of single-sided paperboard may be improved to a certain extent, and at the same time, the generation of defective products can be reduced
there is a paper guide roller in front of the two-layer paperboard conveyed by the lifting belt to the overpass. Can this new technical means make a breakthrough in the remediation of contaminated soil? Can the soil where poisonous rice grows be eliminated? The angle formed by the paper guide roller and the corrugated roller is relatively small. When the two layers of paperboard are separated from the pressure point of the corrugated roller and the pressure roller, they are immediately guided to the lifting belt. Such a hasty process makes the corrugations of the two-layer paperboard be lifted to the overpass for stacking before they are fully shaped, which will cause degumming and corrugation deformation when pressed by external forces. Take a more vivid example: This is the same as the principle of ironing clothes. If the temperature of the iron is too low or the iron moves too fast, the flatness and shape of the clothes will not be ideal. In order to transfer the heat energy of the corrugating roller to the two layers of paperboard to the maximum extent, so that the two layers of paperboard can get the best bonding and the corrugated setting is more stable, on the premise of not affecting the equipment structure, move the position of this paper guide roller backward by about 10 cm, but at the same time, remove 1/3 of the length of the paper guide installed on the air suction cover. If it is not removed, the two layers of paperboard will hurt the corrugated when walking. After the position of the paper guide roller is changed, the residence time of two teeth of the bonded two-layer corrugated board on the corrugated roller can be increased. It is such a small change that makes the shape of the corrugated more straight and firm; What is more unexpected is that the chicken skin like phenomenon that used to appear on the inner paper is now basically invisible
II. Innovation of the gluing device of the double-layer gluing machine
in the whole corrugated board production line, the double-layer gluing machine is one of the most important parts. The quality of paperboard is good or bad, and the loss rate is more or less, which plays a decisive role here. In addition to the quality of the operators, most of the factors, such as the quality problems such as falling corrugated to one side, substandard paperboard thickness, soft paperboard and warped paperboard, will come from rose ryntz, senior vice president of development and material development of international automotive components (IAC). The base paper used in the production of corrugated board has various gram weights. Due to the difference in gram weights, the thickness of single-sided corrugated board cannot be the same. During the gluing process, the paper gap between the gluing roller and the paper pressing roller cannot be adjusted at any time according to the changes of various grams of paper. Moreover, some operators worry that the gluing is not in place, and they often adjust the paper clearance much smaller than the actual requirements, so that the corrugated board is squeezed during the gluing process and tilted back along the forward direction. The width of the bonding surface between the corrugated paper and the face paper will exceed several times the normal width, making the corrugated board produced unsatisfactory in both strength and appearance
the author was once invited to a carton factory. The corrugated board they produced was basically one-sided. After inspection, it is found that the paper passing clearance between the gluing roller and the paper pressing roller is much smaller than the normal requirements. Ask the manufacturer why the paper gap should be adjusted so small. According to their operators, there will be bubbles when making three-layer paperboard, resulting in many defective products. After the gap is reduced, the blistering phenomenon is gone, but the corrugated is poured out. Customers often complain that the cardboard has no hardness. According to the person in charge of the marketing department of the factory, more than 400 customers have cooperated with them, but so far only more than 80 customers have been left. The main reason is that the quality can not be guaranteed, and the customers have run away, making the enterprise often in a state of loss. The factory is very anxious and urgently hopes to solve the urgent problem. In view of this situation, the author designed a set of new gluing device, discussed with the manufacturer, and commissioned the processing of parts with the approval of the manufacturer. After the installation and commissioning, the results of the products produced are quite satisfactory. No matter what gram of paper, no matter how the thickness changes, the paper clearance can be automatically adjusted, which will not cause damage to the corrugated paper, let alone the phenomenon of corrugated falling to one side. Moreover, the width of the gluing is basically controlled at about 1.5mm at the top of the corrugated, and the glue consumption is reduced by more than 30% compared with the previous. Look at the corrugated board produced. The corrugated board is straight and feels very good. The thickness of the five layer board has increased by nearly 1mm compared with the original. Under the condition of constant production speed, the board is quite flat. The manufacturer is very satisfied that such a good result can be achieved with a small investment this time
the biggest feature of this device is that it will not damage the corrugated board, the glue consumption can be reduced to the greatest extent, the quality of the board can be significantly improved, and the investment is small and the effect is quick. After various investigations, at present, such gluing devices are not available in domestically manufactured equipment, nor are they available in imported equipment. This set of equipment is really suitable for the production of low gram weight paper, and has obvious effects on reducing production costs and improving product quality. So the author is going to apply for a national patent in order to popularize and apply more widely in the future
III. the drying channel is equipped with a spray device to improve the bonding quality and make up for the lack of heat supply.
the adhesive used in the production of corrugated board is raw starch glue. As we all know, it is impossible for raw glue to bond paper and paper together to make cardboard. Only when raw glue becomes mature at a certain temperature can it have bonding effect. This process is called "gelatinization". The temperature required for gelatinization is about 60 ℃, which is not difficult for enterprises with boilers to provide steam. However, some enterprises cannot use coal-fired boilers due to strict local environmental protection requirements. The steam they use is the residual steam provided by thermal power plants. Due to many units and long pipelines, the steam pressure delivered to the machine can only reach about 0.6MPa. Such steam pressure is difficult to ensure the production of qualified corrugated board
the author has met two carton factories. The steam they use is provided by the thermal power plant. The produced cardboard will "click" when it is bent by hand. If you tear it with a little force, the cardboard will be completely separated. There are many white powder objects piled on the thin knife and paper separating knife base of the slitter, which are the solidified products of the adhesive. This phenomenon indicates that the adhesive has not been completely gelatinized. The surface temperature of corrugated roller, preheating cylinder and hot plate is detected with a thermometer. The high temperature is 150 ℃, and the low temperature is only 130 ℃. The surface temperature like this is quite different from the actual required temperature. Because the bonding point of corrugated board is in the middle of one or more layers of paper, the surface temperature of the hot plate must meet certain requirements in order to change the raw rubber into mature rubber in such a position. Generally, the surface temperature of medium speed machine shall not be lower than 170 ℃, and the surface temperature of high-speed machine shall be higher. Because when the two-layer paperboard after gluing enters the drying channel for compounding, the adhesive is required to reach the gelatinization temperature in an instant, and then it is bonded under the cooperation of pressure, so the bonding effect is more satisfactory. If the surface temperature fails to meet the requirements, the gelatinization temperature of the bonding point will not be reached instantaneously, but will gradually rise. When the gelatinization temperature is reached, part of the water applied to the corrugated surface adhesive will be evaporated and part of it will be absorbed by the paper fiber. The effect of such a bonding process is certainly not satisfactory. So the enterprises that use centralized steam supply can not make cartons? The answer is No
let's do an experiment first: take two pieces of paper, one with high water content and the other with low water content. At the same time, we put it on the hot plate, put our hands on the paper, and feel which paper is hot first. The result is that the paper with high water content is hot first. This experiment tells us that the heat transfer capacity of paper with high moisture content is faster than that of paper with low moisture content. This is the same principle as why the four-layer paperboard processed by the production line is always bad, and the paperboard can be firmly bonded together after water treatment. According to this principle, a set of steam spraying device is installed at the front end of the drying channel, a row of holes are drilled with 1/3 of the water pipe, and the nozzle is installed. The width of steam spraying is controlled according to the size of the paper. The nozzle with large door width is opened, and the nozzle on both sides is closed with small door width. Such treatment can add two conditions conducive to bonding. One is to appropriately increase the moisture content of the tissue paper entering the drying channel, which can speed up the transfer of heat energy. Second, because the steam with high temperature is sprayed, it can help the gelatinization of the adhesive. After strengthening the pointer and thread wheel of the spray device, we can see the produced cardboard. When it is bent by hand, the "click" sound disappears; When tearing with force, most of it is the tearing of paper fibers, rather than the separation of the original adhesive.