Every die-cutting die-cutting - die cut size is not allowed and flash

Fourth, the control method of die cutting inaccurate and burr issues

With the need, the die-cutting process in paper products has become more and more important. This not only creates grooves after printing, but also allows for hand-holding, helium, and the like. It is more convenient not to use a slotting machine and die-cut after printing to avoid the defects caused by the die-cut after printing.

At present, the die-cutting technology has three methods: flat-flattening, round-flattening and round-pressing. However, no matter which die cutting process is used or which die cutting mode is used, some quality problems will occur to varying degrees. In this paper, we only analyze the dimensional inaccuracies and burrs that appear in the die cutting process.

There are many reasons for the inadmissibility of die-cutting, that is, there are plate-making problems, as well as problems with equipment and raw materials.

The size problem should first check whether the size of the die-cutting board during the production process is correct. For example, to draw a die cut diagram, this is the first key link of the die-cutting plate. The accuracy of the die cut diagram size is directly related to the final size of the product. If you are drawing on a wooden board, using computer proofing and laser cutting of the board will have less of an error. On the contrary, the use of hand-drawn wood patterns and hand-cutting will be larger compared to the error. Therefore, the dimensional error during drawing and cutting is less than 0.5mm.

The size of the device is not caused by the reason; it is also an important factor. Especially in the circular press soft die cutting machine is more prominent. Due to prolonged use and wear, the circumference of the anvil roll becomes smaller, causing an error. Another reason is that due to the small gap between the plate roller and the anvil roller, the pressure is large, the back knife is tilted, and the feed and output dimensions are not uniform. This requires that the shrinkage is properly adjusted to compensate for dimensional errors when designing drawings. In the semi-automatic round die-cutting die cutting machine, since the die plate cannot be mounted on the die-cutting plate, the cardboard may be sprinted to cause size problems after die-cutting. This requires a slow speed during the operation. The feed and the output must be manually pressed against the cardboard to ensure the size. There are also dimensional issues in flattening die cutting machines. Due to prolonged use, the eccentric wears, and the moment of contact between the cutting board and the cutting board generates a slight misalignment, commonly known as the "end bucket", which is about 0.5 mm to 1 mm, and the size after die cutting is also affected.

Excessive moisture or warpage of raw materials and corrugated board is also a cause for inaccurate dimensions. Ordinary corrugated board machine water is basically 14% -18% or higher, more humid. If the cardboard is directly die-cut after leaving the machine, the dimensions are compared; However, for a period of time, when the water content is less than 10% after the water is dispersed, the cardboard will be retracted, the overall paperboard size will be smaller, and the size of each part will be different. The 1m-long paperboard will shrink by about 4mm~6mm. Therefore, it is very important to grasp the moisture of paper and board. Each batch of cardboard must be measured with a quick moisture meter moisture content, depending on the size of the water to arrange the cutting time. If the moisture is too large, it should be placed in the cardboard for 4 hours after the natural drying and then the next process of production, the general factory delivery of water in the 10% ± 2.

The main cause of die cutting burrs is caused by the fact that the die cutter is not sharp, the anvil plate is not even, and the pressure is adjusted improperly.

Before making the cutting board, you should first select a quality die cutter. Because the paper fiber structure is loose, it is required that the die cutter must be sharp and smooth to reduce the friction of the fiber. Die cutters often use blades repeatedly and become dull. If the number of secondary cutters is relatively small, the production efficiency will inevitably decrease. This is uneconomical in the production and operation of the company. The cutting knife should be selected according to the different products and different papers produced. During the production process, the wear of the knife edge should be checked frequently and the tool should be changed in time.

The adjustment of die-cutting pressure is also very important. Proper pressure adjustment can extend the service life of the tool. On the contrary, the cutter is damaged quickly. In the course of operation, there will be partial imperfections, and it is often unreasonable to compensate for this defect by means of pressure. In this case it is possible to take a partial pad, but to handle it properly, die pressure should be maintained evenly.

The aforementioned "die bucket" problem of the die-cutting die cutting machine can also cause flashes. A die-cut variety will be cut at one place for a long time. The knife mark will appear on the anvil plate, and the cutting and dislocation of the die will directly affect the sharpness of the die cutter and cause frequent replacement of the cutter. This phenomenon should be solved in time. In addition, due to the long-term die cutting of products of various shapes, the anvil plate has uneven marks. To solve this problem, simply using pressure or padding paper does not solve the problem. Only the replacement of the new anvil plate is required.

There will be other problems in the die-cutting process, just to mention the above two issues for reference. Only in the actual work of cattle continue to accumulate experience, good at finding problems, and can find the reasons in a timely manner, take appropriate measures and countermeasures, some problems are not difficult to solve.

Recently, at Tianjin University, the company has developed and developed a new process for direct die-cutting of cardboard boxes. This process is still the first in the country, and the technology of die-cutting prototypes has reached the international level. It completely replaces the tedious physical labor such as manual cutting, inserting, and arranging, which greatly saves manpower and material resources. The most gratifying is that the laser die-cutting process completely eliminates the troubles of a series of problems such as the inaccurate size of the original process and burrs. After the die-cut cartons are clean and beautiful, the boxes can also be laser-printed with various patterns, names, dates, etc. Recently, it has applied for a national patent and passed expert appraisal. Laser direct die-cut carton is a gratifying breakthrough after laser engraving rubber plate and laser cutting die-cutting plate, and it is also a major innovation of laser technology applied in the packaging industry, which should be promoted and used.

Author: Wu Cunsheng China Packaging Import and Export Company in Tianjin carton plant

Source of information "Corrugated carton" 2005, 9