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How to effectively solve the burst box burst angle, burst problems
Dec 11, 2017

In the dry season, due to the water, the box in the die-cutting, bonding and packaging process produces explosion angle, the burst problem often plagued many packaging and printing companies. Now, let's take a look at how senior technicians handle this type of problem.


one. cause


1, caused by improper pressure burst


1.1 floor indentation groove foreign body, leading to sharp increase in pressure when die-cutting. This is a common cause of bursting in production and also a devastating cause. It will break the whole dark line, resulting in product scrap.


1.2 running version, that is, die-cutting version or walk-through version, making the wire fell on the outside of the indentation groove. Burst caused by this kind of reason mainly concentrates on the dark line in the same direction, because the cutter or creasing knife does not cooperate closely with the wood formwork, and deflects under the pressure condition.


1.3 The thickness of the steel wire and indentation groove width of the selection and the paper material does not match. According to the requirements of the die-cutting process, for different paper should be used in different steel, and different thickness of the bottom plate and a different dark line width, if not match, it is easy to cause dark burst.


2, die cutting version of the production process caused by the burst


2.1 production of die-cutting version of the steel position improper handling or steel truncated left burr. In the die-cutting products if there is surface treatment, such as coating. The burrs left on the steel wire during the die-cutting can damage the pull-up strength of the surface film and can not burst when the product is molded.


2.2 dark line at the steel knife blade and interface. Due to the interface is not smooth in the die-cutting will occur when tearing.


2.3 pressure knife knives sponge pad inappropriate position occurs when the pressure burst phenomenon, the pressure knife deformation, damage can also cause pressure burst line.


2.4 Knife on the knife and the line with the reasonable. Especially in the design did not take into account the thickness of the paper, the knife and the line can not be effectively avoided in the lap, interference in the molding, making the Department over-concentrated stress, resulting in a burst.


3, material quality problems


3.1 Paper moisture content is too low, the paper becomes brittle. This phenomenon occurs more in winter, because the winter dry weather, the relative humidity in the air is low, will directly affect the moisture content of the cardboard, resulting in pressure cardboard after the break, the average base paper moisture content control in the upper limit (8% -14%);


3.2 paper coating material Biaxially oriented polypropylene film has a slight gap, resulting in reduced tensile strength. Film is a relatively common surface treatment of paper, the main material is BOPP film, if the BOPP film damage before die-cutting will result in the bending after die-cutting BOPP film can not force the resulting burst. Membrane burst occurs only in the film layer, with the force point will increase along the burst direction of the extension, the bottom of the paper did not burst, indicating that nothing to do with the paper, such as film has not broken the paper has broken the film has nothing to do with the paper problem.


3.3 paper to the wrong paper. In die-cutting, if the indentation steel wire and paper fiber perpendicular to the direction of the paper fiber radial damage, the dark line is easy to bend, forming a good, small angle; if the indentation steel line parallel to the paper fiber direction, the paper in the horizontal direction Damaged, the dark line is not easy to bend, forming a rounded corner, a large angle, for the outer layer of paper bailout, easy to rupture. Paper of this direction has little effect on the cutting of sheet-fed products, but the molding is not good, but not easy to burst line, but for card-mounted card products have a greater impact, if not handled properly, not only not forming Good, but also easy to burst line, mainly parallel lines of dark lines in different locations burst line, and the other direction does not burst line.


3.4 Corrugated configuration is too high. Burst and transverse crush strength of the base paper is one of the influencing factors. If the paper is too low folding resistance can easily lead to burst.


3.5 mold using time is too long. In the die-cutting version of the long-term use of the pressure line after the knife will be loosened, resulting in the die-cutting process pressure bouncer bounce, resulting in cardboard pressure burst. As a result of prolonged use of rubber pads, rubber pads caused by bump pressure burst.


two. Process improvement


(1) There is a burst of foreign matter in the indentation groove, which strengthens the sampling inspection in the production and controls the sampling at 200 times. This problem is more intuitive, easy to judge, to clean up foreign bodies in a timely manner, to keep the bottom of the clean


(2) Found that the running version of this situation should immediately re-version, and lock the die-cut version and the bottom plate.


(3) There is a commonly used calculation method for the burst caused by the thickness of the steel wire, the indentation groove thickness and the material mismatch:


Die-cut cardboard


Let A be the thickness of the base paper, B the width of the dark line, C the thickness of the paper jam, D the thickness of the steel wire, then: DC; AC; B = (C × 1.5) + D


Die-cutting corrugated cardboard


Let A: the thickness of the bottom paper, B: the width of the dark line, C: the thickness of the corrugated cardboard (card mounting tile), D: the thickness of the steel wire, E: the thickness of the corrugated cardboard after the flattening should be: DE; ; B = (E × 2) + D


(4) If there is burr or cutting edge on the steel plate in the cutting board, it can be used to eliminate the burr or edge of the indentation knife and round or replace the thick knife with the grinding wheel or file. If using two thin knives, the combined effect will be better.


(5) in the production of die-cutting at the dark line to try to make a circular arc angle or a steel knife forming.


(6) When the pressure bursts appear when the position of the sponge tape is improper, you can use the sponge pad to attach it to the die crimping knife to help destroy the corrugated paper at the pressure line, so as to solve the bursting phenomenon, Sponge pad can not be too soft, should use its own hard bar.


(7) For the moisture content of the paper, the cardboard should be promptly produced after cutting die-cutting, storage time is not easy to reduce the relative humidity on the moisture content of the cardboard, for low moisture content of the cardboard, the board can be coated with water to reduce the burst phenomenon .


(8) set of version is not allowed to cause burst, make a set of actions after the plate and pre-folded 180 degree test, visually check the indentation line is offset.


(9) should always check the mold and found the knife is loose to be promptly repaired or re-made.


(10) The improvement plan for the burst due to the paper wire to the problem is:


a. Do not Biaozhi paper box to the vertical line with the main molding, easy to shape.


b. mounted two layers of color box tile and paper to be vertical, so color box molding only have the same degree of stiffness.


c. mounted three-tier (watt-board) can be based on the allocation of watts properly adjust the wire.


(11) Improvement of burst due to the toughness and folding resistance (configuration) of the paper:


a. The toughness and folding resistance of paper mainly depend on the content of wood pulp in paper making. The higher the wood pulp, the more long fibers that make up the paper, the better toughness and folding endurance, and vice versa.


b. Burst and tank pressure requirements higher Corrugated configuration will be higher with the corresponding requirements of the opposite side of the paper will be higher then toughness and folding good face; corrugated configuration of the relative requirements of the opposite face Zhang reduce;


c. The company also needs to purchase a testing equipment to test the raw paper when it is being fed. It can not only decompose the weight and whiteness.


(12) film quality improvement program to cause burst:


a. replace the film of raw materials;


b. change the direction of the film on the paper;


c. Modification of the die-cutting knife plate, at the knife and the U-shaped corner of the extension of the hole at the aircraft to be raised from the pressure line 0.5mm-0.7mm, slow down in the cushioning force when folded;


(13) the thickness of the material and the size of the scale improvement program.


a. for different materials, D mold in the design of the R angle must be greater than the thickness of the material;


b. Knife and the line and the plane with the hole position can not be formed in the conflict or interference, to be reasonable to avoid, especially framed corrugated products in the main line with the tile when the same direction is prone to burst.


c. We have to work toward a low weight and high configuration, we can not blindly pursue high configuration.


three. Environmental factors and standards


(1) The temperature in the workshop is kept balanced


(2) Control of water content when laminating paper (18 ± 3)


(3) appropriate water content when die cutting products (18 ± 3)


(4) die-cutting machine pressure regulation (70% of the end of the paper blanking the rest of the paper to make up broken)


(5) die cutting line width, thickness (paper flattened × 1.5 = groove width)


(6) die-cutting knife detection (visual, steel ruler, vernier caliper)


(7) molding method


a. Need to paste the main line to fold 180 degrees.


b. shake off the cover up and down more than 135 degrees.


c. Vice line to fold greater than 135 degrees.


d. corrugated board to be folded 90 degrees.

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