Low-weight, high-strength micro-corrugated indentation technology

Low weight, high-intensity miniature corrugated products are quietly entering the carton market in China. Many companies have learned the advantages of low-weight, high-strength, miniature corrugated papers in replacing high-gram heavy-duty white cardboards in terms of cost and structural compressive strength. However, the micro-corrugated paper is different from the traditional white cardboard in terms of technical level both in printing and in post-processing. Therefore, in order to truly let micro-tiles enter the carton packaging industry in an all-round way, they must understand and master these differences in these technologies before they can enter the practical stage. Now make some concise statements on the micro-corrugated indentation technology for the industry to discuss.

The key word used to replace the high-gram heavy-duty white card paperboard with a low-heavy, high-strength miniature corrugated cardboard is the "precise folding." This is extremely important in post-processing automatic gluing boxes and automatic loading of production lines when loading finished products. Another key word is "a crease does not burst," which is an important measure of product quality.

The general corrugated board indentation presses the dent from the inside, that is, when the indentation is die-cut by the flat-press die-cutting machine, the printing face is downward; and when the white-cardboard is pressed by the flat-press die-cutting machine, it is from the outward direction. Pressure, that is, the printing surface. Therefore, when the corrugated paper is indented, the inner liner is dented outward, so when the box is folded, the outer liner is stretched and stretched. This kind of indentation method is based on the glue bonding point of the corrugated core paper and the face paper along the corrugation pit line, and the indentation line is easy to form an irregular deviation (ie, the indentation line is not straight, the angularity is not clear), and the backing paste box is And on the automatic loading line caused adverse effects.

The white cardboard indentation uses an indentation negative template to form a convex circle on the inside of the cardboard. The convex circular line causes the inner layer of the cardboard to form delamination peeling along both sides of the marking line. The inner layer peeling on both sides makes the folding of the back lane very regular. No deviation.

In the indentation micro-corrugation, the author believes that the same way as the white cardboard should be used, consider the printing surface facing upwards, from the outside to the inside pressure, while using the indentation negative template. Although the microvarnish does not form the inner layer peeling along the indentation line after the indentation like the white cardboard, but the outer paper will form a single pit, and the inner paper will form a parallel concave line along both sides of the convex line and simultaneously flatten it. The corrugating medium in the mark pits allows the rear fold (along the indentation line) to have a good effect similar to that of the cardboard indentation line. The two horizontal lines of the outer paper and the inner paper, together with the corrugating medium sandwiched in the middle, can solve the problem of irregular lines caused by the corrugated paper at the glue point.

In fact, when the F, N miniature corrugations are indented, indentation from the outside to the inside or indentation from the inside to the outside can be made, depending on the actual situation. In order to get better indentation effect, it is recommended to use flat indentation line instead of the round indentation line generally used in white cardboard indentation. This reduces the micro-cracks in the indentation line, and it is these tiny cracks that can cause the mark to burst when it is folded.

Paper stretching is also one of the main causes of mark burst during die cutting. This is mainly due to the uneven and excessive pulling force caused by die cutting and indentation. Since the micro-corrugation is thicker, the indentation of the female template is also deeper, and the tensile force caused by the facing paper is greater during the indentation, resulting in minute cracks. This problem is more likely to occur if you use a fast-attached bottom mold strip, because the bottom mold strip (Matrix) is not flat, all round surfaces, tend to cause uneven surface, and the paper is not evenly pressured and stretched. Therefore, the selection of eraser (sponge) on the knife plate is very important. Place some non-porous sponge along the knife line (specific specifications can be asked for material suppliers). It helps to eject the die-cut miniature corrugated in time and can reduce scratches. And micro cracks.

The micro-corrugated creases, in a nutshell, flatten the middle corrugated core paper pit. Therefore, core paper and pits have a great influence on the indentation quality. In the same version, it is better to use the same corrugated paper with the same corrugated paper. In addition, a good crease effect can be obtained by narrowing the width of the indentation groove and increasing the depth of the indentation. However, this method has higher requirements for paper selection for micro-corrugated board. All of the above-mentioned points of indentation technology, when applied to the indentation of micro-corrugated paper, have to be tested and adjusted according to specific conditions to achieve the best results.

about the author

Zheng Zheng, after graduating from university in 1983, joined Hong Kong Gaohua Printing Equipment Co., Ltd. as a sales representative to engage in sales work. Immigrated to Canada in 1988 and started business in 1989 with PRINTECH EQUIPMENT INC. to manufacture, sell and service post-press equipment in North America. Established a joint venture company Anshun Machinery Manufacturing Co., Ltd. in China's Zhejiang Ruian in 1994 to produce semi-automatic die cutting machines and hot stamping machines. Shanghai Xuheng Tiegong Machinery Manufacturing Co., Ltd. was established solely in Shanghai in 1997 and became one of the earliest companies in China to manufacture large format automatic flattening die-cutting presses for the corrugated paper industry.