Systematic Methodology in Carton Size Design

1. Foreword There is a gap between China's packaging industry and the world's advanced level. On the one hand, it is due to technical problems. On the other hand, it is due to the problems of design guidelines. For example, in the packaging design process, only the matter is discussed, and there is no systematic analysis method, so that the designed packaging can not meet the requirements of ergonomics, as well as technical and economical rationality. This point is very obvious in the current carton size design.
The carton is part of the paper package. Paper packaging is the most widely used of all kinds of packaging methods. It can be used both as an inner packaging and as an outer packaging. Cartons are the most common form of paper packaging. It has an easy-to-open handling storage and can be recycled. Repeated use, can be printed on the surface of a variety of text and patterns, relatively inexpensive and other advantages, but also has a certain degree of strength, can provide better promotional and protective effect for the contents of the package, so carton packaging has been getting more and more Wide range of applications. We have reason to pay enough attention to the design of carton packaging.
At present, China has only made clear provisions for the carton box type, but there is no requirement for the size of the carton, mainly by the designer to determine, and the designer in the determination of the size of the carton is mainly to consider two factors: One is to be able to contain the contents of the package; the other is to have sufficient strength. For some large items such as refrigerators, color TVs, washing machines, etc., the size and shape of the cartons really depends on the size and shape of the products, but there are still quite a few times when the cartons are larger than the single products they are packaging. Many, such as clothing, food, and small commodities, the design of carton shape and size at this time is relatively more flexible, but this does not mean that it can be designed. In fact, there are many other factors that govern the size and shape of the carton. Apart from the contents of the package, there are many other factors. Therefore, only by systematically comprehensively grasping all the constraints, can we really determine the size and shape of the carton. The following only illustrates the problem with the packaging carton design for export garments. Since these cartons are generally designed to have a rectangular shape for easy manufacturing, storage, and transportation, the actual size of the cartons is determined by the three dimensions of the length, width and height of the cartons.
2. Constraints on the size of cartons In order to make the issue clear and simple, we do not consider the production and manufacturing of cartons for the moment. We will only analyze the use of cartons. Obviously this will not make our questions and answers meaningless.
The use of cartons in the export of garment factories can generally be summarized as follows:
1) Pack the export garments in a single box, seal them with tape, fill in the necessary text instructions, and then bundle them with plastic tape.
2) Loading. There are two ways: First, the carton code is loaded on the pallet along with the pallet, which is convenient for automatic or mechanized loading and unloading. It is a common method; the other method is to directly place the cartons in the truck compartment or Inside the container.
3) Carton is shipped to the station terminal, unloaded, and loaded into the container. Of course, sometimes this step will be done directly at the factory.
4) After the carton arrives at the export destination (country), it usually has to be transported by car to the wholesale center or distribution center for code placement.
5) Place the garments (usually along with the cartons) on the shelves, and the distribution staff will pick them up according to the list of distributors or distributors.
6) The empty carton will either be used as a half-pack or recycled.
In the process of use, the constraints on the size of the packaging cartons mainly include the following five aspects:
1) Ergonomics factors. In the stacking, binding, half-year, and the order of the clothing, according to the type, color, size on the shelves, all need to be moved by a person's cartons. If the size of the carton is poorly designed, it may make the operation of the worker inconvenient. If a home export garment factory produces jeans, a single-layer corrugated carton pack of 800 (long) × 800 (wide) × 200 (high) mm is used. After removing the straps and lids, the jeans are heavy. When both sides of the carton are moved by hand, a downward convex phenomenon occurs in the middle of the carton. The two hands operate very hardly, not to mention sometimes it is necessary to put the carton along with the clothes to the 2m high distribution shelf. Another example is a carton used by a factory. For 1150 (L) × 400 (W) × 600 (H) mm, this size of carton is very difficult for one person to operate. What's more, I also found in the investigation that there is a factory carton that is 1 meter long. 80 cm wide, 60 cm high, gross weight more than 60 kilograms, the average person does not even want to move, the distribution center had to open the box on the ground, and then remove the clothes into a smaller cardboard box and then sent to the distribution shelves, Increased labor costs, I am afraid that this increase in the cost will eventually be counted as export manufacturers.
2) The size of the tray. The main consideration here is the surface utilization of pallets and the stability of palletizing goods.
3) The dimensions of the freight cars.
4) The size of the container space.
Both of the above factors are to take into account the full use of volume to facilitate loading and unloading operations.
5) With the size of the shelves. Here to consider the ease of operation, in particular to prevent the cartons can not be placed in the shelves.
3. The relationship between the carton size and the constraints In the following, let us analyze in detail how the carton dimensions should be designed to meet the above five constraints.
1) Constraints on ergonomics. The strength of the person carrying the object and the person's posture (this mainly involves bending over, moving halfway, the distance between the two hands leaving the body, the distance between the two hands, the height of the two hands, etc.) and the operation method (this mainly involves Whether one-handed or two-handed, whether it is lifting or lifting, whether it is pushing or pulling, and whether the center of gravity of the object falls within the plane formed by both hands and the body, whether it is on the connecting line of the hands, etc. The relevant ergonomics information manual should be viewed. Here just want to simply start from one or two factors, discuss how to grasp the size of the carton from the perspective of ergonomics.
Figure 1 shows the average weight and height of an object lifted by two hands when the forward distance of the hand leaving the knee is 25 cm (the best knee forward distance) and 50 cm. Figure 2 is a graph of the relationship between the average weight of an adult man with a dual-use liftable object and the forward distance from the knee-exiting hand when the vertical distance above the knee is 102 cm.
It can be seen from Figure 1 that the weight that can be lifted by both hands is closely related to the height at which both hands are located, and is also seriously affected by the distance from the hands in front of the body. In the process of using the carton in this example, the process that affects the height of the hand carrying box has six months of processes, the stacking process, and putting the clothing on the allocated rack. This factor directly affects the allowable maximum gross weight of the carton, and indirectly affects it. The volume of the carton is the three dimensions of the carton.
Figure 2 clearly shows that when the hands are within 50 cm of the chest, the lifting force remains almost constant, and when this distance is exceeded, the lifting force decreases sharply with the distance, which is actually a factor. Limits the width of the carton. According to this restriction, the carton can theoretically be 1 meter wide, but since both hands need to send the carton forward a certain distance during the carrying process, the width of the carton is actually much smaller than this. Between the opening distance of the hands and the lifting (lifting) force of the hands, there is also a curve similar to that shown in Fig. 2, which will restrict the length of the carton.
In addition, it is worth pointing out that one hand's weight-bearing ability is less than half of the negative gravity of both hands. In the handling process, except that the open distance of the hands remains basically unchanged, the height and the forward distance of the hands are constantly changing, so the problem needs to be analyzed dynamically.
For ease of operation, except for special circumstances, one person should consider handling.
From the point of view of man's operation, the cartons are certainly smaller, but this does not mean that the smaller the better. Too small cartons will undoubtedly increase the use of packaging materials, increase the operation and affect the area usage rate of other transportation tools (such as trays).
2) Tray constraints. A pallet is a medium that converts static cargo into dynamic cargo. It can pile together many items and form containers of the same size and shape, facilitating product circulation and mechanized loading and unloading. It is therefore a commonly used storage and transportation package. There are many different types of tool trays, but the factors that most affect the size of the cartons are the size of the trays and the way of stacking. International ISO organizations have established international standards for tray sizes, which are 800×1000mm, 800×1200mm, and 1000× respectively. Three kinds of 1200mm, and China's current promotion of the use of the tray size has some differences, such as the Department of Transportation to promote the use of the tray size is 850 × 1250mm. Obviously, exports should be subject to international standards. For the sake of simplicity, we only take the closest international standard tray (800 x 1200mm) as an example. Also, only 5 positive and negative staggered pallets (Figure 3) and 4 pieces of rotating interleaving are analyzed in the palletizing mode. The code pallet (Figure 4) is used as an example for analysis. As for the use of overlapping pallets or crisscross pallets, the analysis can be similarly performed.
The palletizing method shown in FIG. 3 can be rectangular in cross-section, and can effectively utilize the surface area of ​​the pallet. In the palletizing method shown in FIG. 4, the section must be square in shape, and the hole is formed in the center, which reduces the pallet's capacity. Surface utilization, but the stability of this palletizing method is good.
If the palletizing method shown in Fig. 3 is adopted, the width a of the carton should be 120/3=4cm. However, due to the actual palletizing, the articles are allowed to exceed the trays, theoretically each side can exceed 5cm, so the carton The width can be slightly larger than 40 cm. If no gap is left, the length b of the carton should be 120/2=60 cm. Since 60+40=100 centimeters have more than 80 centimeters in tray width (theoretically allowing more than 4 centimeters per side), the length should be 44 centimeters, but only from the stacking stability if it is not allowed to accommodate various vehicle volumes. It is possible to use a length of 60 cm or more. If you use the palletizing method shown in Figure 4, you can only use the method that only considers the stability of the pallet, otherwise the surface utilization of the pallet is too high. Low. In order to reduce the central hole, the aspect ratio of the carton should be reduced as much as possible. The minimum value is the above 60 (length) × 40 (width) cm, and the maximum value can reach 70 (length) × 50 (width) cm.
3) Constraints on the transport vehicle compartments and containers. Transport vehicles mainly refer to van-type trucks. Currently, there is no uniform standard for the size of vehicles. If the truck is used with pallets, the length and width of the cartons have been analyzed and considered when considering the constraints of the pallets. The height of the cartons should be determined based on the height of the vehicle, ie, the height of the cartons = height of the interior of the vehicle - pallets Thickness - Job Clearance/Crate Stacking Job clearance is generally 10 cm.
If the goods are directly placed in the compartment, the length, width and height of the cartons must be compatible with the internal dimensions of the vehicle to fully utilize the volume of the compartments, ensure the stable positioning of the goods, and facilitate the loading and unloading operations. There is a multiple relationship between the length and width dimensions of the carton and the length and width of the car. This is similar to the analysis of container constraints. Containers are currently a commonly used transport packaging tool. China has issued a series of national standards for the external dimensions and weight of cargo containers in 1978. It is basically compatible with the international ISO standards and should be referred to the corresponding standards when designing. For the sake of simplicity, the following analysis and discussion will be made on the case of a one-ton container for rail freight. Its dimensions are as follows:
External dimensions: 900×1300×1300mm
Internal dimensions: 830×1260×1144mm
Weight: 186kg
Load: 814kg
Total weight: 1000kg
Obviously, the size of the carton is 620 (length) × 570 (width) × 400 (height) mm is the best, then just put eight cartons, taking into account only the second floor, and the tray size constraints, the carton The width and height of the two dimensions can be swapped. It is also worth pointing out that in the end it should be checked whether the load requirements are met. Moreover, international transportation containers are generally over 20 tons, which is mainly for the convenience of container ship transportation.
4) With shelf constraints. The shelves are similar to the shelves used in supermarkets. There are generally five floors. The total height is about 2.5 meters. It is about 3 meters long and about 1 meter wide. When installed,