Improvement of flatness in the production practice

2022-08-10
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Improvement of flatness in corrugated board production practice (3)

the board is in a negative arch horizontally

it is known that the face paper is 200g/NF grade B imitation kraft paper, with a moisture content of 8%; Air pressure 1.ompa/C NF; The speed of the production line is 50M/min. Foreign countries generally adopt the improvement method of full-automatic clamping:

(1) the length of the heating surface of the surface (clamp) tile paper through the preheater is tested by high parameters respectively, and the products are increased by 0.9 to 1.4, 0.6 to 1.12 times in Jinan new era gold Testing Instrument Co., Ltd

(2) reduce the length of the heating surface of the preheater or use a small amount of steam spray

(3) the speed of the production line increases to about 60m/rain. The paperboard is in a negative arch shape in the longitudinal direction

improvement method:

(1) the face paper is in front of the three-layer preheater to reduce the movement resistance and the rotation braking force of the cylinder paper

(2) the guide wheel and tensioning wheel of the lining paper in front of the three-layer preheater increase the movement resistance. After proper adjustment, the original longitudinal arch can disappear

the paperboard has a negative arch in the longitudinal direction

it is known that the face paper is 200g/M2b kraft paper with a moisture content of 13%; The (clip) corrugated paper is 150g/m2 high-strength corrugated paper with a moisture content of 10%; The lining paper is made of 200g/m2 grade B imitation kraft paper with a moisture content of 8%; Air pressure 1.ompa/cm2; The speed of the production line is 50M/rain

improved method

(1) the length of the heating surface of the surface (clip) tile paper through the preheater is increased by 0.9 to 1.4 and 0.6 to 1.1 times respectively

(2) reduce the length of the heating surface of the preheater or use a small amount of steam spray

(3) the speed of the production line increases to about 60m/min. The paperboard is in a negative arch shape in the longitudinal direction

improvement method

(1) the face paper reduces the movement resistance in front of the three-layer preheater

the rotation braking force of the small cylinder paper

(2) the guide tension of the Liwa line in front of the three-layer preheater increases the movement resistance

the paperboard has positive and negative arches

because there are generally two kinds of positive and negative arches, the improvement methods are different, which only shows the common horizontal positive and negative arches

it is known that the face paper is 180g/m2 kraft paper, with a moisture content of 8 and a value of 14%; The air pressure is 1.1MPa/C m2; The improvement method of the production line speed of 70m/min

(1) in the transverse positive arch area, the product series of each set of mold in the face paper bureau is reduced by steam spraying

(2) in the transverse negative arch area, the paper is partially steam sprayed

fog

(3) the speed of the production line is reduced to about 60m/min

(4) 180 for the Liwa paper. Direction adjustment

in addition, there is a remedy, that is, for some large arched cardboard just made from the production line, use about 10 pieces as a stack of positive and negative stacking, and then add a pressing plate on the top, so that the cardboard will be subject to the external force of positive and negative flattening during the storage of semi-finished products, and a good flatness can be achieved after a few hours (according to the ventilation and heat dissipation conditions of the factory room)

assumptions and suggestions

at present, with the improvement of the production automation level of the packaging industry, multi-function machine operations such as paperboard printing, die cutting, slotting and corner cutting, bonding, binding, binding and other operations, as well as the machine packaging production line of carton users, have been widely used. The requirements for flatness are higher and higher, and the paperboard that does not meet the requirements will be automatically stopped or withdrawn by the packaging production line. We believe that there should be a standard for the flatness of corrugated board, so that operators and quality inspectors can follow the operation detection and control the process quality

the flatness of corrugated board must be measured after it is placed horizontally without any external force, and the chord height is taken as the measurement value. The flatness is divided into three levels:

the first level accuracy is suitable for the production of multi-function machines such as printing die cutting, slotting and corner cutting, and is used for machine packaging cartons with high accuracy

secondary precision is suitable for the production of printing die-cutting machines, and is used for packaging cartons with high precision

the three-level accuracy is suitable for single machine production such as printing, slitting indentation, slotting machine, etc., and is used for packaging cartons with general accuracy

improve and perfect the corrugated board production line equipment

(1) the preheater required by each layer of paper, especially the preheater required by the surface paper, should enable the length of the heating surface of the paper to be arbitrarily adjusted according to the vanadium battery cost attitude (wrap angle)

(2) there should be enough space for each paper to emit water after passing through the preheater, especially to ensure the space for the facial paper to emit water

(3) the area that emits moisture after preheating of each paper needs to be equipped with electric fan ventilation device

(author/Shi Wen)

China packaging daily -- paper packaging weekly

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