Packaging Box Type and Dimension Design
Abstract: With increasingly higher demands for packaging box functionality, a reasonable box type and dimension design is crucial for a multi-functional packaging box. Therefore, how to design reasonable box types and dimensions according to relevant standards is a question worth exploring.
Keywords: Packaging box type; Dimension design
The increasing use of packaging boxes across various industries has led to higher functional requirements from users. In terms of cardboard box structural design, especially in containerized transportation and shelf storage, reasonable dimensions, shapes, and materials not only save costs and provide optimal packaging solutions but also ensure the most effective protection of products during long-term freight transport. Under these circumstances, the structural and dimensional design of packaging boxes has become increasingly important.
Packaging Box Type Standards
The dimensional design of cardboard boxes begins with determining the product nature and box type. Only after determining the box type can the dimensions of each component be designed and calculated.
International Carton Standards There are two main categories of international carton standards. One category consists of international carton standards approved by the International Board of Packaging Industries (EBOC) and jointly developed by the Federation of European Packaging Board Manufacturers (FEFCO) and the Swiss Association of Paperboard Manufacturers (ASSCO). The other category comprises national standards from Japan and the United States. International carton standards use simple 4- to 8-digit numerical codes to represent carton types, and illustrations of various carton types are available in the standards.
Uniform serial numbers indicate different carton structures within the same carton type category. Modifications are changes made by different manufacturers to the standard carton type. Different manufacturers' modification suffix codes represent different carton types, but they should be unique to each manufacturer. These suffix codes facilitate the creation of CAD/CAM libraries or dedicated carton image libraries.
For example, the commonly used Type 02 carton, also known as a slotted carton, is formed from a single sheet of cardboard, and its integrated top and bottom flaps allow for closure. In cardboard box factories, joints are typically joined using stapling, adhesives, or tape. The joint length depends on the thickness of the packing board, generally ranging from 25 mm to 45 mm. Type 02 boxes also have a bottom-insertion structure, designed to prevent contents from leaking out from the bottom. Type 02 boxes are flat during transport; when in use, the contents are inserted and the flaps are sealed, making them the most widely used type.
In my country, packaging box codes are based on the type of packing board, divided into three categories, each further subdivided into five types, corresponding to the type of packing board. The codes, specifications, and applications of each type of packaging box can be found in national standards. Type 1 boxes are mainly used for export and transporting valuable goods, and do not use B or BB corrugated board; Type 2 boxes are mainly used for transporting domestically sold products; Type 3 boxes are mainly used for transporting short-distance, low-value goods.
When designing or selecting packaging boxes, appropriate packing board should be considered, including the corrugated board type, number of layers, and base paper specifications, which are clearly defined in relevant standards and documents.
Packaging Box Dimension Design Before determining the structural dimensions of the packaging box, it is essential to consider the maximum outer diameter, nature, and shrinkage tolerance coefficient of the contents, as well as whether the contents are a single unit or a set. Simultaneously, various accessories added to protect the contents must also be considered. This necessitates considering the influence of multiple factors on the structural dimensions of the packaging box in the design and structural layout.
Dimension Specifications The specifications of a cardboard box are generally expressed using its internal dimensions (length, width, and height), given in the following order and code, in mm:
a. Length (L): Long side dimension of the box's internal base area;
b. Width (B): Short side dimension of the box's internal base area;
c. Height (H): Dimension from the top to the bottom of the box.
The dimensional design of the packaging box includes the design of its internal dimensions, manufacturing dimensions, and external dimensions. The inner diameter is the internal space of the assembled box; the outer diameter is the external outline of the assembled box, which can be expressed as the actual manufactured size plus the thickness of the packaging board used; the manufacturing size is the size used in the manufacturing process, which can be expressed as the inner diameter plus the thickness of the packaging board used.
3. Joint Size Design Boxes are formed by gluing and nailing joints. The joint size is generally determined by the number of corrugated layers and the factory's process level. To prevent damage to the printed surface of the main box face (LH side), the joint should generally connect to the LH side. The joint size for single-flute is generally 35 mm to 40 mm, for double-flute 45 mm to 50 mm, and for triple-flute 50 mm.
Dimensional Correction Issues Packaging boards generally need to be molded to achieve good bending. Molding damages the structure of the packaging board, causing the inner liner to shrink and the outer liner to stretch. This bending change makes the stretching dimension of the packaging board a basic dimension of the box design. Therefore, the inner diameter of the packaging box should be slightly shorter than the distance between the creasing and crease when the box is unfolded. This reduced size must be factored in, and this added dimension is closely related to the thickness of the packaging board used. In actual production, appropriate correction factors and additional dimensions must be selected based on the specific equipment used. Correction factor values can be found in tables.
Packaging boxes are generally designed based on their inner diameter. This is because the inner diameter is relatively easy to determine; it is achieved and determined by physical measurement or by combining and arranging the outer diameter in a reasonable manner. However, in actual operation, both freight calculations and the volume indicated on the box must be based on the outer diameter. Therefore, in packaging box design, not only must the manufacturing dimensions be determined based on the inner diameter, but the outer diameter must also be calculated based on the manufacturing dimensions.
Of course, the outer diameter of the carton can also be determined based on the inner diameter of the pallet or container, ensuring that the length, width, and height of the carton are compatible with the transport vehicle, enabling mechanized transport and improving transport efficiency. Due to different stacking methods, the vertical projected area of the stacked objects should be suitable for the pallet dimensions. If the dimensions of the carton, calculated progressively from the inside out, closely match the dimensions calculated progressively from the outside in, the optimal packaging carton size can be obtained. Of course, the best design should still proceed progressively from the outside in.
In actual production, customers often only provide the dimensions or style of the contents, requiring us to calculate the outer diameter and manufacturing dimensions of the carton. This is especially important for products transported in containers. While tools can be used to directly measure the dimensions of packaging boxes, the indentation lines can lead to inaccurate results. Measurements of used, recycled cardboard boxes, in particular, should be rigorously calculated to ensure accurate dimensional design, smooth pallet or container loading, and effective protection of the goods. A good carton design can save significant transportation costs.
Design Methods and Principles
Packaging structural design starts from the actual conditions of packaging and production, and is based on scientific principles to design the external structure and internal accessories of the packaging. The design must ensure sufficient strength, rigidity, and resistance to environmental factors. From the perspective of packaging objectives, two aspects must be considered: first, the primary function of protecting the product; and second, meeting the important characteristics of modern packaging, such as transportation and processing characteristics.
Qualified cardboard box products begin with correct structural design. Designers must not only truly understand the client's intentions but also be familiar with subsequent processing techniques. Only in this way can the client's intentions be translated into a qualified product, ensuring smooth subsequent processing. Before starting the design process, designers must understand the nature, shape, size, and weight of the contents; the arrangement, transportation, and stacking methods of the contents; the storage environment, transportation route, and time of the contents; and information such as the cardboard box type and manufacturing materials.
Domestic cardboard box design suffers from some technical and guiding principles issues, lacking systematic analysis. Consequently, the designed packaging fails to meet the requirements of ergonomics and technical and economic rationality. This is particularly evident in cardboard box size design.
my country only clearly stipulates the box type, but lacks specific requirements for the box size, leaving it mainly to the designer. Designers primarily consider two factors when determining cardboard box dimensions: first, the capacity to accommodate the contents; and second, sufficient strength. In fact, besides the contents, many other factors constrain the size and shape of cardboard boxes, such as ergonomics, pallet dimensions, truck bed dimensions, container space dimensions, and shelving dimensions. These factors are both independent and interdependent; both packaging functionality and convenience must be considered. Therefore, only by systematically and comprehensively grasping all these constraints can the correct cardboard box dimensions be determined.
In conclusion, cardboard box size design is a crucial aspect of packaging box structural design. A qualified cardboard box should possess both protective properties and a pleasing appearance. Especially for boxes that combine sales and transport packaging functions, appropriate dimensions are key to successful design. Changes in size directly affect various performance characteristics of the cardboard box. In short, the structural design of packaging boxes must be determined based on the manufacturing equipment used, different production processes, different flute configurations, and the type and nature of the contents. Only by mastering the structure and dimensions of packaging boxes can one manufacture packaging boxes that protect and beautify goods.
