In color box design, the key to selecting a cardboard combination based on the weight of the contents is to first clarify the protective requirements corresponding to each weight classification. This allows for avoiding excess weight caused by overdesign and achieving a balance between protection and lightweighting. Different contents weights necessitate significantly different load-bearing capacity, crush resistance, and impact resistance requirements for the color box. Lightweight items may only need to withstand minor collisions during transportation and mild pressure from stacking, while heavier items may require greater vertical loads and potential impact from drops. Therefore, it's important to first categorize the requirements by weight and then tailor the cardboard combination accordingly.
For lightweight contents (such as small electronic components and lightweight daily necessities), the cardboard combination should prioritize stiffness and light cushioning, while also maintaining lightweighting. These items don't require heavy cardboard for adequate protection; single-layer corrugated cardboard or high-stiffness single-layer hardboard can be used as the core material. Single-layer corrugated cardboard can utilize a fine-corrugated structure. Its higher corrugation density provides a certain cushioning effect against minor impacts, while preventing the color box from increasing in weight due to excessively thick corrugations. For both the face and back paper, high-strength, thin paper is preferred. This type of paper has dense fibers and strong tensile strength, ensuring a crisp appearance and preventing deformation during transportation. It is also lighter than thicker, standard paper and reduces the amount of glue required, further controlling the overall weight.
For medium-weight contents (such as small appliances and bottled foods), the cardboard combination must strike a balance between load-bearing strength and cushioning protection to avoid excessive weight due to a singular focus on strength. A combination of "single-layer coarse corrugated paper + high-strength face and back paper" or "double-layer fine corrugated paper" can be used. Single-layer coarse corrugated paper has higher corrugation height and greater cushioning space, which can better absorb impact energy during transportation. At the same time, the coarse corrugated paper's load-bearing skeleton structure can support the weight of the contents. If the contents are irregularly shaped, double-layer fine corrugated paper is more suitable. Its staggered structure creates a more uniform load-bearing surface, preventing localized compression and deformation. Double-layer fine corrugated paper is also thinner and lighter than single-layer coarse corrugated paper, reducing the overall thickness and weight of the color box. The face paper should be made of high-strength paper that is scratch- and tear-resistant. The backing paper can be made of thin paper with good adhesion according to the characteristics of the contents, avoiding excessive thickness and added weight.
For heavy contents (such as large household appliances and heavy machinery parts), the paperboard combination should adopt a "high-strength load-bearing + localized reinforcement" strategy to ensure protection while avoiding excessive overall thickness. The core can be constructed from double-layered coarse corrugated cardboard. Its three-dimensional structure creates a strong load-bearing framework, resisting vertical stacking pressure and horizontal impact. The face and backing paper should be made from high-fiber-strength kraft paper or specialty paperboard. These papers offer enhanced resistance to breakage and compression, preventing tearing of the face paper when the color box is loaded. Furthermore, the "entire box is thickened" approach should be abandoned in favor of localized reinforcement. For example, adding a thin layer of high-strength cardboard as padding to concentrated stress areas such as the bottom and corners of the color box, rather than increasing the number of corrugated layers overall, can enhance protection in key areas while minimizing the overall weight of the color box, achieving the goal of "focused protection, overall lightweighting."
The additional characteristics of the contents should also be considered when designing the cardboard combination to avoid inadequate protection or wasted weight due to overlooked details. If the contents are fragile items (such as glassware or ceramics), even if they are of moderate weight, enhanced cushioning performance is required within the cardboard assembly. Instead of simply increasing the number of corrugated layers, thin cushioning materials (such as lightweight sponge or bubble wrap) can be added to the corrugated interlayer. This can both enhance cushioning and reduce weight compared to thicker corrugated sheets. If the contents are rigid, regular shells (such as metal accessories), excessive cushioning is not necessary. Instead, focus on the cardboard's load-bearing strength, choosing a more compact corrugated cardboard structure to reduce the additional weight added by the cushioning layer.
The key to lightweighting lies in optimizing the cardboard's material selection and structural design, prioritizing "material strength" over "thickness stacking." For example, consider using paper with a high proportion of long fibers as the inner layer. Long-fiber paper exhibits far superior tensile and flexural properties than short-fiber paper. For the same strength, the thickness of long-fiber paper can be reduced, thereby reducing the overall weight of the cardboard. In terms of corrugated structural design, narrow-pitch corrugation can be used instead of wide-pitch corrugation. Narrow-pitch corrugation offers more support points per unit area, greater load-bearing capacity, and a thinner overall thickness, ensuring strength while achieving lightweighting. Furthermore, reducing unnecessary adhesive layers—for example, using integrated corrugated cardboard instead of multiple layers—can avoid the added weight of glue and adhesive layer thickness, further optimizing the lightweighting effect.
Finally, the cardboard composition should be adjusted based on the actual application scenario (such as storage stacking height and transportation method) to ensure a practical balance between protection and lightweighting. For example, if color boxes require multiple layers of stacking, the cardboard's compressive strength should be calculated based on the total stacking weight, and the lowest weight cardboard combination that can withstand that pressure should be selected, rather than blindly using high-strength, thicker cardboard. If express delivery is used, the potential for bumps and crushing during transportation should be considered, and appropriate cushioning should be incorporated into the cardboard combination. However, the density and thickness of the cushioning material should be optimized to avoid excessive cushioning layers. By employing this approach of "demand grading + material optimization + structural simplification + scenario adaptation," the appropriate cardboard combination can be selected based on the weight of the contents in color box design, balancing protection and lightweighting.
