Precautions for production of self-adhesive labels

In the actual production process, the self-adhesive label is affected by the factors of self-adhesive materials, tools, machines and operators, and there will often be phenomena such as the bottom paper cutting through, the die cutting spacing is unstable, the die cutting process is marked off and the waste is poor. Below, the author on the different problems in the process of die cutting for specific analysis, and provide solutions.

Back paper cut through

If the bottom paper cutting problem is generated under the circular die cutting mode, it can be solved by reducing the die cutting pressure. If the problem still exists after reducing the die cutting pressure, then it is necessary to consider the round knife grinding; If it is produced in the flat die-cutting mode, the following possible reasons should be considered: 20x8x10000

Self-adhesive material problem

Xinwei adhesive material has very high requirements for flatness. Some small material manufacturers do not grasp the uniformity of the coating when coating the adhesive, resulting in uneven thickness of the adhesive layer. The self-adhesive label produced with this material will easily have the problem of cutting through the backing paper during the die-cutting process. The die-cutting failure caused by this reason is usually irregular, that is, under the condition that the die-cutting pressure does not change, the phenomenon of cutting through the bottom paper and not cutting through the bottom paper will appear disorderly. It is recommended to replace the self-adhesive material when encountering this problem.

Die cutting base plate material problem

When most flat-pressing die-cutting equipment is working, it is necessary to pad the die-cutting bottom plate under the die-cutting material to avoid direct contact between the knife plate and the steel plate below, thereby extending the service life of the knife plate. In general, the die-cutting bottom plate needs to choose a material with moderate hardness, a certain elasticity, and a flat surface. If the surface strength of the die-cutting bottom plate is not enough, it is easy to deformation after the impact of the knife plate during the die-cutting process, resulting in local pressure changes in the die-cutting, resulting in the bottom paper being cut or even cut through.

When encountering such problems, the operator is often difficult to find the real cause, because the deformation of the bottom plate material is not regular. If the operator finds that the base paper is cut during the production process, it will immediately adjust the local pressure, and it will not be long after the adjustment, and it will be found that other positions also have the phenomenon of the base paper cutting. Over and over again, and finally until the replacement of the die cutting bottom plate after the problem can be solved. Therefore, when adjusting the local die-cutting pressure can not solve the problem of cutting the bottom paper, the staff can try to change a die-cutting bottom plate of other materials to see whether it is effective.

The die cutting blade becomes dull

In the die cutting process, with the increase of the number of die cutting, the die cutter will gradually become dull. In order to continue to cut off the adhesive material, it is necessary to increase the die-cutting pressure, so that it is easy to cause damage to the backing paper. The bottom paper damage is mainly manifested as deep die-cutting marks on the surface of the bottom paper, although it has not been cut from the surface, but it has actually destroyed the fiber of the paper, resulting in greatly reduced tensile strength, and it is very easy to cause the bottom paper to break during the automatic labeling process. Therefore, in the die-cutting process, once the operator finds that the surface of the base paper is too deep, it is recommended to replace the blade immediately.

Die cutting pressure is too large

Too much die-cutting pressure is easy to cut the backing paper. In the die cutting process, the die cutting pressure is not completely unchanged, and its stability depends to a large extent on the quality of the die cutting equipment. Therefore, the operator must understand the characteristics of the equipment they operate in the production process and timely monitor and adjust the pressure of the die-cutting equipment. There are two situations in which the die-cutting pressure is too large to damage the backing paper: If the overall pressure is too large to cause the backing paper to cut, it can reduce the pressure of the equipment; If the local pressure is too large to cause the cutting of the bottom paper, you can reduce the thickness of the corresponding position of the die-cutting bottom plate.

Die cutting spacing is unstable

Cutting distance refers to the distance between labels after die cutting and waste. Under normal circumstances, according to the use of the end user, the die cutting distance between the labels is generally 2~3mm, the tolerance of the distance is ±0.3mm, more than this tolerance, as unqualified products. In daily production, the die cutting distance is often large and small, and the main reasons for this phenomenon are the following three aspects.

Self-adhesive material

Many thin-film self-adhesive materials are affected by the heat of ultraviolet lamps during the printing process, and will shrink and deform, which will be contained in the die-cutting process

The printing cursor spacing is incorrect

The size of the spacing in the die-cutting process is determined by the pre-printed die-cutting cursor. However, due to problems such as the setting of printing step size and equipment accuracy, the final printed cursor will have a small error, which will lead to inaccurate die-cutting time interval.

If the spacing error is regular, it can be solved by adjusting the printing step size. In general, die-cutting and printing have consistency, the first product of die-cutting, the position of the electric eye is also the first product. If the spacing error is not regular, it is considered to be a problem with the printing press, and the printing press needs to be repaired.

Die cutting machine problem

In the process of die cutting, it is usually necessary to track the printing cursor. If there is a problem with the photoelectric eye used to track the printing cursor on the die cutting machine, it will also lead to inaccurate die cutting spacing. In this case, you can try to adjust the optical eye again according to the operating procedure, or shut down and restart the optical eye again; If the problem has not been solved, you need to consider replacing the photoelectric eye. For manufacturers with more than two circular die-cutting machines, the die-cutting material can be replaced with another die-cutting machine for die-cutting, in order to determine whether this die-cutting machine is faulty.

Poor die cutting and waste discharge

The so-called die-cutting label (also known as flying mark) refers to the phenomenon that the self-adhesive label is brought up with the waste edge during the die-cutting process. Serious die-cutting and waste bad phenomenon will not only cause waste of raw materials, but also bring a lot of trouble to the post-process. So, what are the reasons that cause the problem of poor die-cutting and waste?

The release force of self-adhesive material is too low

The binding force between the surface material and the base paper is called the release force. If the release force of the self-adhesive material is too low, it will lead to the phenomenon of dropping the label during the die-cutting process. The release force of many self-adhesive materials will change with the change of temperature, and the release force will increase with the increase of temperature, and the reverse will decrease. Under normal circumstances, it is recommended that the production temperature of the workshop is not less than 15 ° C, if the phenomenon of dropping is also generated above this temperature, you can consider whether it is the problem of the self-adhesive material.

Readhesive at die cutting

Some self-adhesive labels have been completely cut off during the die-cutting process, but due to the fluidity of the adhesive, when the die-cutting self-adhesive label passes through the back of the press wheel, the adhesive at the die-cutting will stick together again, resulting in poor labeling or waste discharge. In this case, the self-adhesive material is frozen in the refrigerator and then printed and die-cut, or a piece of alcohol cloth is added to the self-adhesive material during die-cutting, and the alcohol can be filled to the knife mark, so that the adhesive can be blocked.

The die cutter is damaged or the interface is not straight

The blade of the die cutter is damaged or the interface is uneven, which will cause the self-adhesive label can not be completely cut off. When the waste is discharged, the waste edge will take up the self-adhesive label that is not completely cut off, resulting in the die-cutting of the label. This cause of the drop is generally regular. At the same time, because the edge of the self-adhesive label is not completely cut off, there will be a phenomenon of connecting with the waste side and "burr". In the event of such a problem, it is recommended to replace the blade or completely repair the knife plate.

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