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The packaging box not only needs to have bright colors and an elegant design but also requires the box to be well-formed, perfectly square, with clear and smooth creases, and without any cracking. However, during production, some tricky issues often arise, such as the packaging box forming with an overly open top, which directly affects consumers' trust in the product.
The packaging box not only needs to have bright colors and an elegant design but also requires the box to be well-formed, perfectly square, with clear and smooth creases, and without any cracking. However, during production, some tricky issues often arise, such as the packaging box forming with an overly open top. This is especially true for pharmaceutical packaging boxes, which are used by millions of patients. Poor-quality packaging boxes can directly affect consumers' trust in the product. Additionally, pharmaceutical packaging boxes are produced in large quantities and have smaller dimensions, making the problem more challenging to solve. Based on my practical work experience, I would like to discuss with my peers the issue of pharmaceutical packaging boxes forming with an overly open top.
There are many reasons why packaging boxes may form with an overly open top, but the decisive factors mainly fall into two categories: paper-related issues, including the use of roll paper, moisture content, and the direction of the paper fibers; and process-related issues, including surface treatment, die-cutting plate production, the depth of the creases, and the layout format. If these two key issues can be properly addressed, the problem of box formation will also be resolved.
It is well known that most of the paper used nowadays is roll paper, some of which is imported.
Due to constraints in storage space and transportation, the paper must be slit domestically, and the slit paper has a short storage time. Additionally, some manufacturers, due to financial constraints, tend to buy paper as needed, so most of the slit paper is not completely flat and still has a tendency to curl. If the slit paper is purchased as flat sheets, the situation is much better, as there is at least some storage time after slitting.
Furthermore, the moisture content of the paper must be evenly distributed and balanced with the surrounding temperature and humidity; otherwise, over time, the paper may deform. If the cut paper is stored for too long without being used, the moisture content at the edges may be greater or less than in the center, causing the paper to warp.
Therefore, when using cardboard, it is best to use the paper on the same day it is cut and not store it for too long to avoid paper deformation.
Another factor that contributes to boxes forming with an overly open top is the direction of the paper fibers. The paper fibers are less likely to deform in the horizontal direction but more likely to deform in the vertical direction. If the direction of the box's opening is parallel to the direction of the paper fibers, this issue of the top opening up will be more pronounced. During the printing process, the paper absorbs moisture, and after surface treatments such as UV coating, polishing, and lamination, the paper may deform to varying degrees. Once the paper deforms, the tension between the surface and the bottom of the paper is not uniform, and since the sides of the box are already glued and fixed during formation, the only direction for the box to open is outward, resulting in an overly open top after formation.
1. Surface treatment of pharmaceutical packaging usually involves processes such as UV coating, lamination, and polishing. These processes subject the paper to high temperatures and dehydration, significantly reducing its moisture content. Additionally, the stretching process may cause some paper fibers to become brittle and deform. This is especially true for cardboard over 300g that is laminated using water-based machines, which tends to stretch more significantly. The laminated product often has an inward curve, which typically requires manual correction. The temperature of polished products should not be too high, usually controlled below 80°C, and the product should typically be allowed to cool for about 24 hours before proceeding to the next production step to avoid creasing.
2. The quality of the die-cutting plate also affects box formation. Hand-made plates are usually rougher, with less precise control over specifications, cutting, and bending, which is why most manufacturers have switched from hand-made plates to laser-cut plates made by professional die-cutting companies. However, whether the sizes of the reverse locks and the high-low lines are set according to the paper's weight, whether the cutting line specifications are suitable for all paper thicknesses, and whether the depth of the cutting line is appropriate all impact the formation of the box. The cutting line is an impression made on the paper surface by the pressure between the die-cutting plate and the machine. If the cutting line is too deep, the paper fibers may deform due to the pressure; if it is too shallow, the paper fibers may not be fully compressed. Due to the elasticity of the paper, when the sides of the box are formed and folded back, the cut edges of the opening will expand outward, resulting in an overly open top.
3. To ensure good creasing, in addition to using the appropriate creasing lines and high-quality steel knives, attention must be paid to adjusting the machine pressure, selecting the right adhesive strips, and following proper installation procedures. Many printing manufacturers use paperboard to adjust the depth of the creases, but since paperboard generally has a loose texture and insufficient hardness, the resulting creases are not very durable. Using imported base materials for the creasing line can produce more durable and fuller creases.
4. Layout formatting is the main approach to solving the issue of paper fiber direction. Currently, the fiber direction of paper on the market is generally fixed, mostly in the longitudinal direction. When printing color boxes, multiple boxes are printed on a single sheet of double, triple, or quadruple-sized paper. The general principle is that, without affecting product quality, the more boxes that can be printed on one sheet, the better, as this reduces material waste and lowers costs. However, if material costs are prioritized without considering the fiber direction, the resulting box formation may not meet the customer's requirements. Ideally, the paper fiber direction should be perpendicular to the direction of the box opening.
5. In conclusion: The issue of packaging boxes forming with an overly open top can be easily resolved if we pay attention to these factors during the production process and avoid potential problems related to paper and processing.
