In the production of self-adhesive label, die-cutting is a very important link, the quality of die-cutting directly affects the quality of the final product. The self-adhesive label is mainly composed of three layers: surface material, adhesive layer and backing paper (coated with silicon oil layer). The die cutter is required to cut through the adhesive layer at the die joint, but it can not damage the silicon oil layer. This kind of die-cutting technology is called "precise die-cutting". In the actual production, due to many factors, it is difficult to achieve this ideal situation, often produce a variety of die-cutting quality problems, it can be said that accurate die-cutting is our goal, but also guide us to effectively solve the problem of die-cutting quality magic weapon.

 

Here is a summary of the daily production process of bangheng Technology Co., Ltd.

 

 

　　1、 Cutting through of bottom paper
　　In small and not serious cases, the pressure can be adjusted and die cutting speed can be accelerated. In large area, the roller must be repaired in serious cases. Generally, the reasons for the die cutting and cutting of the bottom paper are as follows:
　　1. Too much die-cutting pressure
　　Too much die-cutting pressure can easily lead to the bottom paper layer being cut, but this simplest principle is often ignored by operators in the daily production process. It seems that the die cutting process seems simple to operate, but it is not easy to do well. Proper adjustment of die-cutting pressure is a basic work, but it is difficult to make the die-cutting pressure not completely unchanged in the process of operation. According to the author's understanding, the stability of die-cutting pressure is related to the quality of die cutting equipment to a large extent. The pressure of good die cutting equipment is relatively stable and the pressure of some die cutting equipment is stable The quality is worse. Therefore, the operator must understand the characteristics of the die cutting equipment they operate in the production process and timely monitor and adjust the pressure of the die cutting equipment so that it can be kept within the proper range to ensure that the bottom paper is not damaged during die cutting.
　　2. Die cutting blade blunt
　　At present, the service life of die cutting blades in the market varies from tens of thousands to hundreds of thousands of times according to their materials. It is important to remind you that the die-cutting blades will become dull gradually with the increase of the number of times of use until they can not be used. And in this process, the die-cutting effect is also changing slightly. At first, the blade is sharp, so it is easy to cut through the material. We only use a small die-cut pressure. As the number of times of use increases, the material die-cutting blade becomes more and more blunt. At this time, we have to cut the material by increasing the die-cutting pressure, which will easily cause the damage of the material bottom paper. The main performance is that the surface of the bottom paper will have a deep die-cut mark. These marks are caused by the impact of the bottom paper. In this case, although the bottom paper is not cut through the surface, the fiber of the bottom paper itself has been destroyed, which greatly reduces the tensile strength of the bottom paper. Such label products are easy to break the bottom paper during the process of automatic labeling. Therefore, it is necessary to remind the general colleagues in the production process to pay attention to the impression on the bottom paper when die cutting, otherwise it will affect the strength of the bottom paper. If this happens, it is recommended to replace a new blade for the die cutter plate.
　　3. Quality problems of die cutting base plate
　　Most die cutting equipment will pad the die cutting bottom plate under the material when working, so as to avoid direct contact between the cutter plate and the lower plate, thus extending the life of the cutter plate. Generally speaking, die cutting base plate needs to choose soft and hard materials with certain elasticity and flat surface (such as PVC plastic board). But the author found that some materials used to make die-cutting bottom plate have insufficient surface strength, which is easy to deform after being impacted by the cutter plate during die cutting, which results in the change of local pressure of die cutting, which leads to the bottom paper being cut and even cut through. Operators who encounter such problems often find out the real reason. Because the deformation of the base plate material is not regular. Operators often find that the local pressure can be adjusted immediately after the bottom paper cutting is cut. After that, it is not long since other positions have been found that the bottom paper cutting is damaged again. This tired to cope with but always can not find the real reason, until the other die-cut board after the problem is solved. Therefore, it is reminded that once there is any irregular local pressure change, you can try to change the die-cut bottom plate of another material to see if the problem is solved.
　　4. Material quality issues
　　There are many manufacturers of adhesive labels in China, and their products are also of different quality. The flatness of the adhesive material is very high. Some small manufacturers do not master the uniformity of thickness in the process of coating adhesive, which leads to the uneven thickness of the product. Such adhesive materials are easy to cause the bottom paper to be cut in the die cutting process. The failure caused by this kind of reason also shows that the bottom paper can not be cut through the surface layer in the case of no change of die cutting pressure. In case of this problem, it is recommended to replace the adhesive material.
　　5. The problem of die cutting machine
　　The instability of die cutting pressure may also lead to the bottom paper cutting, but this phenomenon rarely occurs. After all, the market in the vast majority of die-cutting machines are tested. But it also does not rule out the possibility of sudden problems with some old equipment that has been used for many years. If it is die cutting machine problem, it usually shows that the whole pressure is too heavy or the pressure is too light in normal operation process, and most of them are irregular. This situation can be contacted with die cutting machine manufacturers for maintenance.
　　2、 The spacing of die cutting is not correct
　　Die cutting distance refers to the distance between labels written after die cutting and waste disposal. Generally, the die-cutting distance of adhesive label is between 2-3mm according to the customer's usage. In daily production, there are often some phenomena of inaccuracy of die cutting spacing, which mainly shows that the spacing is large or small, and such label products also do not meet the quality standards. So what is the reason for this?
　　1. Incorrect spacing of printing cursor
　　The size of the spacing in the die cutting process is determined by the die cutting cursor printed first. But in the printing process, some equipment caused by such or such problems that the printing cursor spacing has a small error, leading to the inaccuracy of the spacing of die cutting. This kind of situation usually shows that there is a small error between the label spacing. Sometimes the label spacing will gradually increase or decrease and have periodicity, which is regular in the period of printing or printing. If this kind of problem is encountered, die cutting process can not be solved, and it may be to find the reason of printing error and solve it.
　　2. The problem of die cutting machine
　　The above mentioned die cutting process usually needs to track the printing cursor, if there is a problem in the photoelectric eye used to track the cursor on the die cutting machine, the die cutting spacing will be inaccurate. This reason leads to the inaccuracy of die-cutting spacing as the accuracy of the spacing of printing cursor is unstable in the die-cutting time distance, and it may be regular or irregular. And after a period of operation, the photoelectric eye can not scan the cursor. In this case, we can try to adjust the photoelectric eye again according to the operation procedure or restart after the shutdown and restart. If the problem has not been solved, we need to consider replacing the photoelectric eye of die cutter. Of course, for the manufacturers with more than two die-cutting machines, we can also judge whether the die-cutting equipment has problems by changing materials to another die-cutting machine.
　　3. Material deformation
　　Many film adhesive materials will shrink and deform when they are affected by UV light heat during printing. In the process of die cutting, it is easy to have the problem of inaccuracy of spacing. In this kind of problem, we can measure whether the actual distance of printing cursor is smaller than the design space. If the judgment is caused by this problem, the spacing irregularity must be controlled during printing, we can reduce the chance of material deformation by reducing UV lamp power or increasing printing speed.
　　3、 Die cut "flying mark"
　　The so-called die cutting "flying mark" refers to the phenomenon that labels are brought up with the waste side during die cutting. Die cutting "flying standard" is very common in daily production, and serious "flying standard" phenomenon will cause waste of raw materials and bring many troubles to the later process. The reasons for die cutting "flying mark" are as follows:
　　1. Material release force too low (too low temperature)
　　The binding force between the surface layer and the bottom paper of the adhesive material is called the parting force. If the parting force of the adhesive material is too low, it is likely to lead to "flying mark" in the die cutting process. It is important to note that the parting force of many adhesive materials changes due to the influence of temperature. Generally speaking, the temperature rise and the parting force increases and decreases on the contrary. If the temperature in winter workshop is too low, it is likely to cause the drop of the parting force of the adhesive material and the die cutting "flying mark". Generally, it is recommended that the production temperature of the workshop should not be less than 15 ℃. If there is a phenomenon of "flying mark" above this temperature, it can be considered whether it is the quality of adhesive material.
　　2. Too much glue on die cutter
　　In the process of die cutting, the residual glue will be accumulated gradually on the cutter plate. If the residual glue accumulates to a certain extent, the edge of the label will be brought up, which is equivalent to a pre stripping of the die-cut label. In this way, it is easy to take the label up when the waste is discharged, which causes die cutting "flying mark". Therefore, the residual glue on the cutter plate should be cleaned timely, and the method of sponge pad on the cutter plate can be used to prevent the pre stripping of label by the cutter plate. When necessary, you can also use some silicone oil sprays on the knife plate to reduce the amount of residual glue on the knife plate.
　　3. The die cutter is damaged or the interface is not even
　　If the blade of die cutter is damaged or the interface is not uniform, the label can not be cut completely. When the waste is discharged, the label that is not completely cut will be taken up and the die cutting "flying mark" will be caused. The "flying mark" caused by this reason is generally regular, and the edge of the label will be connected with the waste discharge side because it is not completely cut off. In case of this problem, it is suggested to replace the blade or repair the cutter plate thoroughly.
　　4. Label area too small
　　The smaller the label area, the more prone to the phenomenon of flying marks, because the smaller the area of the label, the less the force required to peel the label from the bottom paper, so the label can easily peel off the bottom paper and generate "flying mark" as long as it is subjected to a little external force. The label with small area and 10 * 10 mm is recommended to be manually discharged.
　　4、 Waste discharge edge fracture
　　1. The waste disposal edge is too thin and the material strength is not enough
Many label manufacturers in order to pursue economic benefits in the design process of the label waste side design too thin, resulting in the waste side strong enough and broken. Generally speaking, the width of waste side of paper type adhesive material is required to be more than 3mm, and that of film type adhesive material shall be at least 1mm.
　　2. The adhesive material has too much parting force
　　There are many unqualified adhesive materials with too large parting force. Some of them are difficult to separate the surface layer from the bottom paper. When the die cutting and waste disposal, the pull force of the waste discharging side is less than the parting force of the material, it is easy to break. Therefore, it is better to check whether the parting force is qualified before the processing and production of the adhesive.
　　3. Material edge damage
　　The edge damage of the dry adhesive material during transportation or processing is also one of the common reasons for the fracture of waste disposal side. Therefore, it is necessary to avoid the edge damage of raw materials caused by bumping or extrusion during transportation and processing, and do not cause trouble to the production of post die cutting.
　　4. Waste roller too fine
　　For some die cutting equipment with too fine waste roller, it is easy to break the waste discharge side because the pull force of the waste disposal side passes through the waste discharge roller is too large. For the fracture of waste disposal edge caused by this reason, we can use replacement of waste roller or wrapping a layer of sponge on the waste discharge roller to increase its diameter.
　　5. Label shape profile
　　There are many tags designed to be shaped like a pentagonal star or triangle. Such labels are easy to break due to the stress concentration of waste disposal due to their own design. In general, it is better to use manual waste disposal or not to exhaust waste when special label is encountered.
　　5、 Label of residual glue pollution during die cutting
　　In the process of die cutting, the problem of the label surface pollution caused by residual glue will appear. This kind of phenomenon is especially easy to appear in the die-cutting process of film adhesive label, because the surface layer of film adhesive material has poor bonding force with glue, and the glue is more likely to leak out during die-cutting. There are the following solutions to these problems:
　　1. Keep die cutting plate clean
The glue of the number is accumulated on the knife plate gradually in the process of die cutting, and then transferred from the blade plate to the surface of the adhesive material. Therefore, it is very important to keep the die cutting plate clean. During the production process, it is better to spray some silicone oil sprays on the knife plate to reduce the accumulation of glue on the knife plate.
　　2. The workshop temperature should not be too high
　　If the temperature in the workshop is too high, the fluidity of glue will be enhanced, which will make it easier to exude the pollution label. Generally, the temperature of the adhesive label production workshop is between 20-25 ℃, which can greatly reduce the leakage of glue. At the same time, remind the general colleagues that the storage temperature of adhesive label is also 20-25 ℃, and glue above this temperature is easy to seep from the edge of die cutting and affect the normal use of end users.
　　3. Choose the right material
　　There are many kinds of glue used in the adhesive materials. Many enterprises generally use the glue with low fluidity for the film materials which are easy to produce the adhesive permeability, so it is not easy to produce the phenomenon of glue infiltration in the die cutting process. Therefore, before the production of adhesive label, we can communicate with the material supplier to select the materials that are most suitable for their own production to reduce the surface pollution caused by adhesive penetration.
　　6、 Angle and hardness of die cutting tool
At last, we want to remind you that there are differences in the angle and hardness of die cutting tools used for different adhesive materials. At present, the angle of die cutting tool in China is 42 degrees and 52 degrees. The 42 degree angle die cutter is mainly used to cut film adhesive material, while 52 degree angle die cutter is mainly used for paper sheet type adhesive material. For the die cutting tool with different hardness manufacturers have different standards, some manufacturers in the division of shore hardness in some manufacturers have their own standards, but generally speaking, the film label die-cutting cutter features a larger hardness but poor wear resistance, paper label die-cutting knife hardness is relatively small but wear-resistant some. Different manufacturers will have products for these two kinds of label materials, and the specific application can communicate with the manufacturer. Here is mainly to remind you of the difference.
　　7、 Die cut overflow
　　Die cutting overflow refers to the glue spilling on the edge of label after the process of label die cutting. It is a common defect of adhesive products. The overflow of adhesive will lead to the appearance defects, printing pollution, peeling and other problems. The problem of die cutting overflow is also solved in the following aspects:
　　1. performance analysis of label materials: different types of materials have different types of adhesives, processing properties of adhesives, etc. Therefore, consult with the material supplier for relevant performance characteristics before production, and select materials suitable for your processing process.  
　　2. label processing and storage environment control: the temperature of label processing and storage environment should be controlled in the range of 23+-3 ℃, humidity should be controlled in the relative 55+-5%, too high temperature and humidity will improve the fluidity of adhesive. In actual production, we can obviously feel that during summer production, die cutting overflow is more common, on the contrary, it is very rare in winter, That's what it is.  
　　3. quality control of label die cutting: it is necessary to use sharp tools to die cut labels. Blunt angle blades will cause the label adhesive to be extruded, which will lead to the phenomenon of label edge overflowing during die cutting. Too deep die-cutting pressure will also cause excessive extrusion of adhesive, too shallow die-cutting pressure may cause the drawing phenomenon of adhesive during die-cutting, thus forming overflow on the edge of label or label surface. Therefore, the choice of die cutting tool is the key.  
　　4. label processing process control: it is necessary to avoid sliding friction on labels during label processing, and parts with sliding friction with labels are easy to accumulate die-cut glue, and then pollute the edge of labels. Such overflow phenomenon will show obvious rules and directions in the position of labels