How to ensure the quality of die-cut corrugated boxes

With the increasingly fierce competition in the corrugated box industry and the continuous improvement of market requirements, customers have increasingly stringent requirements for the quality of corrugated boxes, and more and more mold-cut corrugated boxes have been used. In order to ensure the quality of die-cut corrugated boxes, “four materials, one figure, one test, one person” work should be done during the production process.

Four materials

"Four materials", namely four kinds of die-cutting materials: Die-cutting plate, indentation line, die-cutting knife and rebound sponge glue. These four materials directly affect the die-cutting quality of corrugated boxes. The use of high-quality die-cutting materials and their ability to fit together properly is an important guarantee for the quality of die-cutting of corrugated boxes.

Diecutting plate

The requirements of die-cutting plate texture hard, not easy to deformation, pressure resistance, the surface must be waterproof barrier treatment, and polishing, bonding using environmentally friendly glue, no cracking, no Alice. In round die cutting, high accuracy thickness tolerances and surface curvature of the arc plate are also required.

The cutting of the die-cutting master has sawing and laser cutting methods. Saw cutting is currently the main method for the small and medium corrugated box companies to process die-cuts on their own. The work of the sawing machine is to use a special saw blade to move up and down, and on the bottom plate, a narrow groove that can hold steel cutters and steel wires is machined. The sawing machine is equipped with an electric drill, which can drill holes in the bottom plate. After drilling, the saw blade passes through the bottom plate and is then cut. In recent years, laser cutting has begun to be widely used. This method is highly accurate and is performed on a laser cutting machine controlled by a computer. Laser is used as an energy source, and the substrate material is cut by the high temperature generated by the laser.

Indentation line

The indentation line determines the shape of the corrugated box. As the design of corrugated cartons becomes increasingly complex and the precision of manufacturing becomes increasingly stringent, the quality of indentation is of great importance. More and more customers place stringent requirements on the indentation of corrugated cartons.

The indentation line is the key to controlling the passage of the paperboard through the die-cutting machine. If the indentation line is too high, the paperboard will be broken, and if it is too short, the indentation position will be deviated. In order to realize the ideal indentation effect of the corrugated cardboard, an indentation protection strip can be used. Its unique design makes the protection strip lightly press the paper, and the indentation line accurately presses the crease line on the bottom roller.

Indentation lines are mainly divided into two categories: narrow head lines and large head lines.

The narrow head line is used to realize the indentation of the thin material, not only can improve the indentation effect, enhance the corrugated carton pressure resistance, but also save the time for making the slit.

For products that require a wide indentation, large head lines are generally used, which can effectively save kerfs and plate-making time.

It is also important to select the appropriate thickness and height of the indentation line. The thickness of the indentation line is usually 0.7mm, 1.42mm, 2.13mm and other specifications. The height of the indentation line is usually 22-23.8 mm. The selection principle of the indentation line is that the thickness of the indentation line is greater than the thickness of the flattened corrugated cardboard. The height of the indentation line is equal to the height of the die cutter minus the thickness of the flattened corrugated cardboard minus 0.05-0.1 mm.

Die cutter

Choosing the right die-cutting blade plays an extremely important role in die-cutting the success of various corrugated cartons. The performance of die-cutting blades is mainly manifested in the following aspects:

n Pressure required for a material

n cut into the bottom roller condition

n Cutting edge quality

n blade life

n Bending performance

The effect of a good die-cutting blade can not be underestimated, can make the die-cutting machine run at a higher speed, reduce the required die-cutting pressure, improve the waste-disposal effect, reduce the cut-off cracking, reduce the die-cutting dust, and improve the cutting phenomenon. As the bottom roll wear and die cutting pressure are reduced, the life of the die cut can be effectively extended.

The physical process of die-cut corrugated cardboard is when the impact of pressure, the die-cutting blade pierces the cardboard momentarily, the sharp die-cutting blade makes this “instant piercing” softer, so as to achieve a good die-cutting effect, not only die-cutting The cleanliness, no burrs, pulling phenomenon, and the more stable die-cutting process ensure the quality of die-cut corrugated cardboard.

In addition, to ensure the use of die cutters, we must first scientifically adjust the die cutting pressure to prevent excessive pressure. When the pressure is too high, the blade becomes dull at the very beginning of die-cutting, and the subsequent die-cut is actually “broken” rather than cut off. The blunt surface of the blade presses the edge of the paper on the paper. Experiments have shown that the first die cutting of a die cutter is critical to its life. Everyone knows that a new engine needs to be “run-in”, and the same is true for the blade. Only after a good running-in blade can it have a longer life span, resulting in Good die-cutting effect.

Rebound sponge glue

The rebound sponge rubber plays an important role in die-cutting, such as rebounding waste edges, positioning corrugated cardboard boxes, coordinating die-cutting indentations, protecting connecting points, and equalizing pressure, and directly affecting the speed and quality of die-cutting. In different bonding positions, different hardness and elastic rebound sponges are required. When the sponge glue in a certain position lacks sufficient hardness and elasticity, the corrugated cardboard cannot be pressed at this position, and a paper tear phenomenon occurs during die cutting, instead of ideally breaking completely, thus producing paper dust and paper hair. If the spongy rubber lacks resilience, it will affect the speed of the die cutting machine, resulting in frequent shutdown and troubleshooting. In order to ensure smooth and high-speed die-cutting and reduce paper dust and paper hair, it is necessary to use rebound sponge rubber with uniform texture and proper hardness.

Sponge rubber distance is between 1-2mm. If it is too close to the knife line, it will cause the sponge to generate lateral force when it is under pressure. It is easy to damage the joints of corrugated cardboard or corrugated paperboard during die-cutting. Pulling hairs affects the effect of die cutting; if the distance is too far, the effect of preventing the cardboard from sticking will not be achieved.

a picture

"A picture" refers to the die-cut layout outline drawing, which is an expanded view of the die-cut version of the full-page product. If the printing is a full-page imposition system, the die-cut layout profile can be directly output in the printing plate-making process, which can effectively ensure the unity of the printing plate and the die-cut plate. If the printing is made using a hand-made film, it is necessary to draw a cut-out version of the outline according to the actual size of the typeset. During the drawing process, in order to ensure that the die-cutting plate does not disperse during the plate-making process, a number of “bridges” should be left in the large-area closed-pattern part, and the width of the bridge can be designed to be 3 to 6 mm for the small plate version. Large version can leave 8 to 9 mm. In order to make the die-cut version of the steel knife and steel wire have good die-cutting adaptability, the following problems should be paid attention to in product design and layout drawing:

1, the slotted hole should be used as far as possible the entire line, the line should be rounded corners to prevent the emergence of vertical steel knife stitching.

2, the joints of the two lines, should prevent sharp corners.

3, to avoid the connection of multiple adjacent narrow waste edges, should increase the connection part, make them into a piece, easy to clean up.

4, to prevent the emergence of a continuous number of sharp corners, for the non-functional requirements of the sharp corners, can be rounded.

5, to prevent the sharp corner line cut to the middle of another straight line, this will make the knife difficult, steel knife easy to loose, and reduce die-cutting fitness, should be changed to the arc or increase its angle.

Try

"A test" is a die-cut test cut. After the die-cutting plate is processed, it is necessary to first place the die-cut plate on the die-cutting machine for trial cutting. This is also an important link. In the test cutting process, if there is a part of the impermeability phenomenon, it is necessary to perform the padding in the die-cutting position, which is also called "compression compensation." The padding plate is generally made of 0.05mm, 0.1mm, 0.15mm thick pad film. Paste at the bottom of the die cutter to compensate the height of the cutting line. After the pad is completed, the normal die cutting operation can be performed.

one person

"One person" is the human factor.

At present, corrugated box companies generally use hand-made die-cutting plates, and their quality is greatly affected by human factors. As a die-cut maker, you should study while working and continuously improve your die-cut production. For die-cutting machine operators, they should have good operating techniques. They must be very professional in the operation of the machine so that they can play their greatest role and ensure the quality of die-cut corrugated boxes.

In today's rapid economic development, the key to the development of enterprises lies in technological innovation. Only by combining the above factors with technological innovation can we make a qualitative leap in the quality of die-cutting of corrugated boxes.

Reprinted from: Industry Technology (Carton)