In dry weather season, due to moisture, box generates burst angle cutting, bonding and packing process, often bursting problem plaguing many packaging printing enterprises. Below, we take a look at a senior technical staff approach to such questions.
one. cause
1 improper pressure burst
1.1 indentation bottom slot of a foreign body, leading to die-cutting pressure surge. This is in production burst common causes one kind of cause, also damaging a reason. It will make the whole dark line rupture, resulting in product obsolescence.
Running version 1.2, which die plate or bottom plate to walk, so that the wire falls outside groove indentation. This bursting causes are mainly concentrated in the same direction of the dark line is due to the cutter or knife and wooden forms with the indentation does not close, deflected under pressure condition.
1.3 does not match the wire thickness and width of the groove bottom indentation selection and paper materials. Die-cutting process according to the requirements of different paper should be used for different steel wire and the bottom plate of different thickness and different dark trough wide, if not match, it can easily lead to a dark line burst.
Burst 2 die-making process leading to the
2.1 When leaving burrs Die steel production line position mishandled or steel wire cut off. If you die in the surface-treated products, such as film. Pulled strength steel wire die when left burr can damage the surface of the film, the film can not be formed in the product by force, it would have burst.
2.2 blades steel wire dark line at the edge and have the interface. Since the interface is not smooth when you die there will be tearing.
There will be 2.3 Crimping tool sponge pad location inappropriate pressure line burst phenomenon, the pressure line knife deformation, damage may also cause pressure line burst.
2.4 die cutter knife and the line on match is reasonable. Especially in the design did not consider the thickness of the paper, in line with the knife on the lap can not effectively avoid interference occurs during molding, so that where the force too concentrated, resulting in burst.
3 material quality issues
3.1 paper moisture content is too low, the paper brittle. This phenomenon tends to occur in the winter, due to the dry and cold winter weather, low relative humidity in the air, it will directly affect the moisture content of cardboard, paperboard after causing pressure line fracture phenomenon, generally base paper moisture control at the upper limit (8% between -14%);
3.2 Paper coating material biaxially oriented polypropylene film has a subtle gap, resulting in reduced tensile strength. Film is a relatively common paper surface treatment, which is the main material BOPP film, if it causes the bending die after die before BOPP film BOPP film when the injury will not cause stress to burst. Burst the membrane occurs only in the thin film layer, along with all the force point plus direction along the extended burst, the bottom sheet is not broken, indicating that regardless of the paper, such as the film is not broken paper has nothing to do with split film, paper has problem.
3.3 Paper paper misalignment. When cutting, if the indentation of steel wire and paper fiber direction perpendicular to the paper fibers radially destroyed, the dark line is easy to bend, forming a good, small angle; if the indentation of steel wire fiber direction parallel to the paper, the paper is not in the transverse direction damaged, the dark line is not easy to bend, forming a rounded, angle, paper for the outer support force big, easily broken. This paper has little directivity die on sheetfed product, forming just is not good, not easy to burst line, but there is a greater impact card mounted card products, if handled properly, not only molding good, but also easy to blast lines, mainly the paper grain parallel dark lines at different positions critical line, and the other direction is not critical line.
3.4 high corrugated configuration. Bursting and horizontal ring crush strength of the base paper is one of the factors. If in paper folding is too low it will likely lead to burst.
3.5 mold used for too long. After prolonged use die in the die-pressure line knife come loose, resulting in a die cutting creasing knife bounce, resulting in cardboard pressure line burst. Due to the prolonged use of pads, pads causing uneven pressure line burst.
two. Process improvement
(1) There is bursting indentation trough foreign body to strengthen sampling efforts in the production control in 200 sampling time. This problem is rather intuitive, easy to judge, to promptly clean up the foreign body, clean the bottom plate
(2) found that this situation should immediately run edition re-edition, and die-lock and bottom plate.
(3) steel wire thickness, indentation groove bottom thickness and material does not match the burst result, there is a common method of calculation: die jams
Let A: Bottom paper thickness, B: dark groove width, C: jams thickness, D: thickness of steel wire, there should be: D≥C; A≤C; B = (C × 1.5) + D die corrugated board
Let A: Bottom paper thickness, B: dark groove width, C: corrugated cardboard (card mounted watts) thickness, D: thickness steel wire, E: after flattened corrugated cardboard thickness, there should be: D≥E; A≤E ; B = (E × 2) + D
(4) If the die-plate steel wire burr or cutting edge, eliminate creasing knife edge or burr grinding wheel can be used to rasp or rounded thick knife or replace the use of a thin knife two combined with better results.
(5) in the production of Die dark line at the angle or arc to try to make a steel molding.
(6) When the position is not due sponge strips appeared at that time when the pressure line burst phenomenon with a sponge pad attached to the side of the mold pressure line knife, to help destroy the corrugated cardboard at the pressure line, in order to achieve settlement of a burst phenomenon, but the use of not too soft sponge pads should be used itself harder sparring.
(7) for the water content of paper, paperboard after die-out should be produced, stored for too long is not easy to reduce the impact of relative humidity on the moisture content of cardboard, paperboard for low moisture content, can be applied to reduce the water on board burst phenomenon .
(8) registering allowed to cause burst, after registering to do a pre-molding operation and 180 degrees folding test indentation line visual check whether the offset.
(9) should always check the mold, tool found loose to be repaired or redone.
(10) Since the paper wire burst improvement plan for the problems caused by:
a. not laminating wire to the box to be formed perpendicular to the main line, to facilitate molding.
b. two-story box mounted to the tile to be perpendicular to the paper, so that the molding box only stiffness.
c. mounted three (tile class) can be adjusted according to the silk tile configuration.
(11) due to the toughness and paper folding endurance (configuration) caused by burst improvement plan:
a. Paper toughness and folding depends on the content of the paper when the pulp, the higher long-fiber pulp constituting the paper more, toughness, and folding endurance is good, otherwise poor.
. B burst pressure requirements and higher corrugated box will be a corresponding configuration with high demands on glossy paper will be higher then you need a good surface toughness and folding sheets; worse corrugated configuration requirements will be relatively opposite Zhang reduce;
c. Companies also need to purchase a testing equipment, raw materials Paper detect when feed, can not break down just weight and whiteness.
(12) to improve the quality of the film caused by the burst of the program:
. A replacement material film;
. B change the paper feed direction of the film;
. C of the cutting knife version modified on knives at the U-shaped angle and extends to the pressure line of aircraft to put up at the hole 0.5mm-0.7mm, slow down when folded cushion force;
(13) the thickness of the material and the size of the foot angle improvement plan.
. A different material, in the design of R Die angle must be greater than the thickness of the material;
b. with a knife and hole position line and planes can not occur at the time of molding conflict or interference, to be reasonable avoidance, especially mounted corrugated products in the main and tile molding to easily produce the same direction when the burst.
c. We want to move low-weight high configuration operations, can not pursue high-profile.
three. Environmental factors and standards
Temperature (1) the workshop balanced
(2) when laminating moisture control (18 ± 3)
(3) die-cut products at the appropriate moisture content (18 ± 3)
(4) pressure die-cutting machine adjustment (bottom 70% of paper and thrust the end of paper to fill up the remaining off)
Width (5) of the die-cut line, the thickness (paper thickness collapsible groove width × 1.5 =)
(6) die-cutting knife mold detection (visual, ruler, vernier caliper)
Technique (7) of the molding
a. gluing mainline need to fold 180 degrees.
b. shake up and down off the cover is greater than 135 degrees.
c. secondary line is greater than 135 degrees to fold.
d. corrugated board to reflexed 90 degrees.