Improvement of paperboard flatness Improvement of the flatness of corrugated board:
First, the base paper provided by the supplier is required to have a qualified and stable basis weight and moisture content. During transportation and loading and unloading, rain is prevented from getting wet. The basic environmental humidity is maintained during storage in the factory.
The second is that the surface of the paper choice of materials as much as possible using the same type of paper or quantitative, moisture content, the same grade of paper.
Thirdly, the paper with high water content is heated by the heating surface (wrapping angle) of the preheater, and is ventilated by the electric fan to increase the time for distributing water and slow down the speed of the production line. Paper with a small moisture content passes through the preheater ) The length of the heating surface is reduced, natural ventilation and steam spray are used to speed up the production line.
Fourth, the amount of glue on each layer of paper remains the same, and the amount of glue on the entire width of the paper along the direction of the corrugation is even and moderate.
Fifth, pressure stability, traps and other pipe fittings to maintain normal function.
There are many factors that affect the flatness of corrugated board, and the changes between the various factors of flatness will change. Improvements must be made according to local conditions and targeted, and the main contradiction must be resolved. Here are some examples of common problems in the production of single and double corrugated cardboard in our factory.
The paperboard is arched horizontally and known: face paper is 250g/m2 grade A kraft paper with a moisture content of 7.7%; (clamp) corrugated paper is 150g/m2 domestic high-strength corrugated paper, moisture content is 10%; inside paper is 250g/m2 grade B Kraft containing water The rate of 14%; air pressure 1.1Mpa/cm2 production line speed 60m/min. ways to improve:
(1) The length of the heated surface of the (jaw) tile through the preheater (wrap angle) is increased by 1 to 1.6 times and 0.5 to 1.1 times, respectively.
(2) The medium-speed ventilation of the 0.9KW electric fan is adopted for the inner (clamp) tile line moving on the bridge of the production line, and the workshop is opened for natural ventilation.
(3) The face paper is evenly sprayed with a small amount of steam.
(4) The production line speed is reduced to about 50m/min.
Adjusted according to the above-mentioned selection parameters, the original transverse arch can disappear.
Cardboard from the longitudinal negative arch improvement method:
(1) Face paper increases the resistance before the three-layer preheater, and increases the rotational force of the tube paper.
(2) The guide wheels and tensioning wheels of the Liwa paper in front of the three-layer preheater reduce the movement resistance.
Appropriate adjustment of the original longitudinal arch can disappear.
It is known that the paperboard is negatively arched horizontally: the face paper is 200g/m2B imitation kraft paper, the moisture content is 8%, the air pressure is 1.0Mpa/cm2, and the production line speed is 50m/min. ways to improve:
(1) The length of the heating surface of the surface (clamp) tiles through the preheater is increased by 0.9 to 1.4, 0.6 to 1.12 times, respectively.
(2) The paper reduces the length of the preheater heating surface or sprays it with steam.
(3) The production line speed increased to about 60m/min.
The paperboard has a negatively arched longitudinal improvement method:
(1) Face paper reduces movement resistance in front of the three-layer preheater and reduces the rotational force of the tube paper.
(2) Liva paper increases the resistance of the guide wheel and the tensioning wheel in front of the three-layer preheater. Appropriate adjustment of the original longitudinal arch can disappear.
The paperboard is known as a negative arch in landscape orientation: the face paper is 200g/m2B grade kraft paper with a water content of 13%; (clamp) paper is 150g/m2 high-strength corrugated paper, with a moisture content of 10%; and 200g/m2B grade imitation kraft paper is used for the paper. , Moisture content 8%; Air pressure 1.0Mpa/cm2; Production line speed 50m/min. ways to improve:
(1) The length of the heating surface of the surface (clamp) tile through the preheater is increased by 0.9 to 1.4, 0.6 to 1.1 times, respectively.
(2) The paper reduces the length of the preheater heating surface or sprays it with steam.
(3) The production line speed increased to about 60m/min.
The paperboard has a negatively arched longitudinal improvement method:
(1) Face paper reduces movement resistance in front of the three-layer preheater and reduces the rotational force of the tube paper.
(2) The tension in the tension of the Riva line in front of the three-layer preheater increases the resistance to movement.
There are two types of positive and negative arches in the paperboard due to the positive and negative arches. The improvement methods are different. Here, only the common transverse positive and negative arches are described.
Known: face paper is 180g/m2 kraft paper, water content 8 value 14%; air pressure is 1.1Mpa/cm2; production line speed 70m/min.
ways to improve:
(1) The paper is partially sprayed with steam in the transversely arched area.
(2) Local steam spray in the transversely negatively arched area.
(2) The production line speed is reduced to about 60m/min.
(4) Adjust the 180° direction of the liner paper.
In addition, there is a way to make up for this. That is, for paperboards with a large part of arches that have just been manufactured from the production line, a stack of positive and negative stacks of about 10 sheets is placed on top of the rear pressure plate, so that the cardboard is subjected to positive and negative reactions during the storage of semifinished products. Flattening of the external force, after a few hours (according to the plant ventilation, cooling conditions) can achieve a better flatness.
The technical requirements of the proposed and proposed corrugated board are stipulated in the national standard GB6544-86 “corrugated board†which is intended to have the flatness: 2.3 “The surface of the corrugated board is flat...†Currently, with the automation level of the packaging industry production Improvements have been made in multi-task operations such as cardboard printing, tactile cutting, notching, gluing, binding, and tying, as well as in the packaging production line for carton users. Flatness requirements have been increasing, and cardboards that do not meet the requirements It will be automatically shut down or exited by the machine packaging line. We believe that there is a need for regulations on the flatness of corrugated board so that it is easy for operators and quality inspectors to follow the inspection of operations, which is conducive to the control of process quality.
The flatness of the corrugated board shall be measured after being placed horizontally without any external force, with the chord height being a measure. Flatness is divided into 3 levels:
The first-order accuracy is suitable for the production of multi-functional machines such as touch-cutting, slotting, and cutting, and is used for high-precision machine-packed cartons;
The secondary precision is suitable for the production of the open-cutting touch-cutting machine, and is used for the higher precision packaging cartons;
The three-level accuracy is suitable for single-machine production such as printing, splitting indentation, and slotting machine, and is used for explosive carton with a general precision.
Improve and improve the equipment of corrugated board production line (1) The preheater needed for each layer of paper, especially the preheater needed for the surface paper, should be able to adjust the length of the heated surface of the paper (wrap angle);
(2) There must be sufficient space for the paper to distribute water after passing through the preheater, especially to ensure that the paper is distributed in the space where the water is distributed;
(3) Fan ventilation shall be provided in the areas where the papers are preheated to distribute water;
(4) Each paper must be equipped with a steam spray device, and the amount of steam can be arbitrarily adjusted along the direction of the corrugation.
First, the base paper provided by the supplier is required to have a qualified and stable basis weight and moisture content. During transportation and loading and unloading, rain is prevented from getting wet. The basic environmental humidity is maintained during storage in the factory.
The second is that the surface of the paper choice of materials as much as possible using the same type of paper or quantitative, moisture content, the same grade of paper.
Thirdly, the paper with high water content is heated by the heating surface (wrapping angle) of the preheater, and is ventilated by the electric fan to increase the time for distributing water and slow down the speed of the production line. Paper with a small moisture content passes through the preheater ) The length of the heating surface is reduced, natural ventilation and steam spray are used to speed up the production line.
Fourth, the amount of glue on each layer of paper remains the same, and the amount of glue on the entire width of the paper along the direction of the corrugation is even and moderate.
Fifth, pressure stability, traps and other pipe fittings to maintain normal function.
There are many factors that affect the flatness of corrugated board, and the changes between the various factors of flatness will change. Improvements must be made according to local conditions and targeted, and the main contradiction must be resolved. Here are some examples of common problems in the production of single and double corrugated cardboard in our factory.
The paperboard is arched horizontally and known: face paper is 250g/m2 grade A kraft paper with a moisture content of 7.7%; (clamp) corrugated paper is 150g/m2 domestic high-strength corrugated paper, moisture content is 10%; inside paper is 250g/m2 grade B Kraft containing water The rate of 14%; air pressure 1.1Mpa/cm2 production line speed 60m/min. ways to improve:
(1) The length of the heated surface of the (jaw) tile through the preheater (wrap angle) is increased by 1 to 1.6 times and 0.5 to 1.1 times, respectively.
(2) The medium-speed ventilation of the 0.9KW electric fan is adopted for the inner (clamp) tile line moving on the bridge of the production line, and the workshop is opened for natural ventilation.
(3) The face paper is evenly sprayed with a small amount of steam.
(4) The production line speed is reduced to about 50m/min.
Adjusted according to the above-mentioned selection parameters, the original transverse arch can disappear.
Cardboard from the longitudinal negative arch improvement method:
(1) Face paper increases the resistance before the three-layer preheater, and increases the rotational force of the tube paper.
(2) The guide wheels and tensioning wheels of the Liwa paper in front of the three-layer preheater reduce the movement resistance.
Appropriate adjustment of the original longitudinal arch can disappear.
It is known that the paperboard is negatively arched horizontally: the face paper is 200g/m2B imitation kraft paper, the moisture content is 8%, the air pressure is 1.0Mpa/cm2, and the production line speed is 50m/min. ways to improve:
(1) The length of the heating surface of the surface (clamp) tiles through the preheater is increased by 0.9 to 1.4, 0.6 to 1.12 times, respectively.
(2) The paper reduces the length of the preheater heating surface or sprays it with steam.
(3) The production line speed increased to about 60m/min.
The paperboard has a negatively arched longitudinal improvement method:
(1) Face paper reduces movement resistance in front of the three-layer preheater and reduces the rotational force of the tube paper.
(2) Liva paper increases the resistance of the guide wheel and the tensioning wheel in front of the three-layer preheater. Appropriate adjustment of the original longitudinal arch can disappear.
The paperboard is known as a negative arch in landscape orientation: the face paper is 200g/m2B grade kraft paper with a water content of 13%; (clamp) paper is 150g/m2 high-strength corrugated paper, with a moisture content of 10%; and 200g/m2B grade imitation kraft paper is used for the paper. , Moisture content 8%; Air pressure 1.0Mpa/cm2; Production line speed 50m/min. ways to improve:
(1) The length of the heating surface of the surface (clamp) tile through the preheater is increased by 0.9 to 1.4, 0.6 to 1.1 times, respectively.
(2) The paper reduces the length of the preheater heating surface or sprays it with steam.
(3) The production line speed increased to about 60m/min.
The paperboard has a negatively arched longitudinal improvement method:
(1) Face paper reduces movement resistance in front of the three-layer preheater and reduces the rotational force of the tube paper.
(2) The tension in the tension of the Riva line in front of the three-layer preheater increases the resistance to movement.
There are two types of positive and negative arches in the paperboard due to the positive and negative arches. The improvement methods are different. Here, only the common transverse positive and negative arches are described.
Known: face paper is 180g/m2 kraft paper, water content 8 value 14%; air pressure is 1.1Mpa/cm2; production line speed 70m/min.
ways to improve:
(1) The paper is partially sprayed with steam in the transversely arched area.
(2) Local steam spray in the transversely negatively arched area.
(2) The production line speed is reduced to about 60m/min.
(4) Adjust the 180° direction of the liner paper.
In addition, there is a way to make up for this. That is, for paperboards with a large part of arches that have just been manufactured from the production line, a stack of positive and negative stacks of about 10 sheets is placed on top of the rear pressure plate, so that the cardboard is subjected to positive and negative reactions during the storage of semifinished products. Flattening of the external force, after a few hours (according to the plant ventilation, cooling conditions) can achieve a better flatness.
The technical requirements of the proposed and proposed corrugated board are stipulated in the national standard GB6544-86 “corrugated board†which is intended to have the flatness: 2.3 “The surface of the corrugated board is flat...†Currently, with the automation level of the packaging industry production Improvements have been made in multi-task operations such as cardboard printing, tactile cutting, notching, gluing, binding, and tying, as well as in the packaging production line for carton users. Flatness requirements have been increasing, and cardboards that do not meet the requirements It will be automatically shut down or exited by the machine packaging line. We believe that there is a need for regulations on the flatness of corrugated board so that it is easy for operators and quality inspectors to follow the inspection of operations, which is conducive to the control of process quality.
The flatness of the corrugated board shall be measured after being placed horizontally without any external force, with the chord height being a measure. Flatness is divided into 3 levels:
The first-order accuracy is suitable for the production of multi-functional machines such as touch-cutting, slotting, and cutting, and is used for high-precision machine-packed cartons;
The secondary precision is suitable for the production of the open-cutting touch-cutting machine, and is used for the higher precision packaging cartons;
The three-level accuracy is suitable for single-machine production such as printing, splitting indentation, and slotting machine, and is used for explosive carton with a general precision.
Improve and improve the equipment of corrugated board production line (1) The preheater needed for each layer of paper, especially the preheater needed for the surface paper, should be able to adjust the length of the heated surface of the paper (wrap angle);
(2) There must be sufficient space for the paper to distribute water after passing through the preheater, especially to ensure that the paper is distributed in the space where the water is distributed;
(3) Fan ventilation shall be provided in the areas where the papers are preheated to distribute water;
(4) Each paper must be equipped with a steam spray device, and the amount of steam can be arbitrarily adjusted along the direction of the corrugation.
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