1. Introduction China's packaging industry has undergone two or three decades of rapid development, achieving tremendous success. To date, it has initially established a complete packaging industry system and packaging science and technology education system. There are many domestic scholars discussing the overall issues of the packaging industry. The author has also written two articles, one on the dialectical development of packaging machinery in the modern packaging system and the other on the comprehensive research of packaging machinery engineering systems. The article elaborates on its basic characteristics, and the main viewpoints are as follows: (1) The combination of materials, processes, and technologies is the fundamental way to continuously develop packaging machinery. (2) Establishing a diversified, combined, universal, mechatronic, and multifunctional integrated modern packaging machinery system is an important direction for future development, in order to meet the actual needs of packaging of various varieties, small batches, and high efficiency. (3) A comprehensive analysis of the combination elements of packaging machinery engineering systems and the interaction between the system and the environment is aimed at improving the overall function of the system, thereby giving rise to the new concept of "integration of packaging technology and mechatronics technology" to meet the challenges of the new technological revolution. The ancient Chinese story of "Tian Ji's Horse Racing" is undoubtedly a prime example of strategic victory, demonstrating a deep understanding of the overall situation (knowing one's own strengths and weaknesses) and prioritizing key elements (using multiple horse types). Its enduring value remains invaluable. In contrast, in contemporary China's packaging industry, while there are many successful examples, there are also numerous tragic ones. Early on, a research and design unit invested significant manpower, resources, and capital in developing an automatic laundry detergent packaging line. However, failing to grasp that the primary material for effective protection in modern laundry detergent packaging is plastic and its composites, they unilaterally pursued "green packaging materials," deciding to use paper bags. The result was a near-total failure, as the entire batch of equipment (mostly specialized machines) was rejected by society shortly after trial sales. This is truly thought-provoking; a difference of just one or two words in packaging material terminology can have such a severe impact! What exactly is "primary"? Simply put, it means the main element that guides things in a certain direction. However, it is generally believed that grasping the leading role is quite difficult; clearly, without a thorough understanding of the system, it is fundamentally impossible to grasp the leading role effectively. To grasp the leading role, one must use scientific thinking methods to deeply understand the system, gradually identify its regularities, and sift through the complex factors layer by layer. Past experience teaches us that any field should find the correct way to handle the inherent relationship between the overall situation and key points, and between the system and the leading role, to achieve the important significance of using specific points to drive overall optimization. In this way, during implementation, it can reduce decision-making errors and losses in planning and implementation, equipment research and procurement, product production and sales, etc., bringing maximum benefits. Remember, all of this is subject to changes in time and conditions. 2. Development Strategy of the Food Packaging Industry People often say that food is the most important thing for the people. In fact, "most important" means paramount. In the 1990s, the global food industry's total output value reached US$2.2 trillion, ranking above the output value of other industries. Similarly, the total output value of the food packaging industry accounted for more than 60% of the total output value of the packaging industry. This fully demonstrates that food processing and food packaging occupy a very important position in the entire national economy. In the 21st century, it is expected that the focus of development for all countries will remain on properly addressing the fundamental issue of feeding the people (including various special needs of the military and civilians), thus determining that the food and packaging industries are perpetually booming industries with enormous potential and broad prospects. Relevant departments in my country have already officially announced that the food industry will become the largest industrial sector in the country, and it is predicted that the international food processing center is shifting to Asia, primarily to China. This will bring excellent opportunities for my country to continue expanding its packaged food exports. Staple foods should be the main products or the main market of the food industry. In some developed countries, promoting staple foods has already been put on the agenda. It is believed that in the near future, China will also gradually achieve this goal. Therefore, it is necessary to vigorously advocate the industrialized production of traditional staple foods from now on, while actively exploring many emerging fields of non-staple foods, which will surely promote the vigorous development of my country's packaging industry, especially small food packaging. Regarding food packaging alone, it can be divided into two main categories based on its application in the logistics process: sales packaging and transport packaging. Considering that the former directly contacts the food itself and consumers, it places diverse and high demands on all aspects of its inner and outer packaging. Furthermore, from an overall perspective, the materials, containers, processes, technologies, and equipment used in food sales packaging are unparalleled in terms of complexity, variability, and sophistication, possessing greater breadth, representativeness, and driving force. Therefore, food sales packaging plays an undisputed leading role in the entire packaging industry and must be prioritized for vigorous development. 3. Current Status Analysis of Food Packaging Technology Food provides people with essential nutrients. Generally speaking, a person's reasonable nutritional structure should be pyramid-shaped; staple foods are at the bottom, followed by by-products, condiments, and at the top, candies, beverages, and others. Based on this, considering the diverse products commonly found in the food industry, food packaging can be broadly classified into eight categories according to their variety and physical properties: grain processed foods, fruit and vegetable processed foods, poultry, livestock, meat, and aquatic product processed foods, soy, egg, and dairy processed foods, oil processed foods, condiments, candies, and beverages/cold drinks, etc. This lays the foundation for in-depth investigation and specific understanding of the corresponding packaging systems adopted based on different packaging requirements. Here, we focus on analyzing and synthesizing from the perspective of sales packaging to draw some basic regularities: (1) Given the wide variety of food types, their diverse nature, and the constant emergence of new products, and the fact that most of them are organic substances that are easily infected by external microorganisms and subjected to adverse physical, chemical, and mechanical effects, the packaging is required to have strong protective, usable, and promotional functions. As a result, the aseptic, miniaturized, diversified, simplified, mechanized, and automated nature of food packaging has become the mainstream of the times. (2) Regardless of the packaging method used, we must first start from the requirements of the inner packaging and rationally select packaging materials and containers. In general: ① For liquid foods, plastic bottles, glass bottles, metal cans, and bags, boxes, and cups made of composite materials are commonly used. ② For semi-fluid foods, wide-mouthed plastic or glass bottles, and bags, boxes, and cups made of composite materials are commonly used. ③ For powders, granules, and foods mixed with liquids, metal cans, wide-mouthed plastic bottles, and bags, boxes, and cans made of composite materials are commonly used. ④ For single or multiple sets of solid foods in block, sheet, strip, or spherical/hemispherical shapes, larger plastic boxes, metal cans, and bags, trays, and boxes made of composite materials are commonly used. In short, currently, metal and glass bottles, cans, and boxes account for a relatively small proportion of food packaging containers, and this proportion is gradually decreasing, with most used for gift packaging or special packaging. Boxes and trays made of thin cardboard are generally used for outer packaging due to their poor barrier properties. Only bags, boxes, and cups made of composite materials based on plastic film can effectively protect food and enhance its appearance. They are also diverse in shape, easy to process, resource-saving, low-cost, lightweight, and highly adaptable, making them virtually universally applicable (except for gaseous and liquid materials) and suitable for all occasions (land, sea, and air), showing great potential for development. In particular, the combination of inner packaging bags and outer packaging boxes can strongly promote the widespread application of small food packaging. (3) With the acceleration of people's daily work pace, the enrichment of nutritional and health-preserving diets, and the enhancement of environmental protection awareness, there will inevitably be many new requirements for food and its packaging in the future. What is noteworthy now is that, given the rapid popularization of refrigerators and microwave ovens, coupled with the gradual maturation of other related conditions, it will not be long before frozen foods can be developed as convenience foods and fast foods and enter a large number of households and enterprises (including service and tourism industries). At the same time, it is also necessary to develop new technologies and products such as vacuum packaging, vacuum gas-filled packaging and aseptic packaging according to local conditions, so as to organically combine them with frozen packaging and jointly promote food packaging to a higher level. In this way, consumers at all levels place their hopes on small food packaging containers with bags and boxes as the main body. In particular, regarding the issue of comprehensive understanding and ease of use, it is advisable to put forward current views, mainly referring to the packaging being easy to open, easy to place, resealable multiple times, recyclable after use, and safe and reliable. Therefore, it is necessary to take corresponding measures to further improve the bag and box types and realize the scientific and diversified nature of the main body and sealing structure. (4) It is generally acknowledged that in commercial competition, quality and low price must always be taken into account. If this can be achieved, it will not be difficult to capture the market and remain invincible. One way out is to achieve a dialectical unity between reasonable packaging and simplified packaging. The reason is obvious: reasonable packaging also includes simplification, but simplification is not necessarily reasonable (such as the previously eliminated naked thin plastic tube packaging for beverages and the soft paper box packaging with top and bottom lids for biscuits). In fact, from the mainstream perspective, the existing bags and boxes that are not expensive but carefully designed and popular all over the world have an advantage in this regard; because by reasonably simplifying the packaging form and structure as well as related processes and equipment, various consumption and waste in the production and sales process can be greatly reduced, and many unstable factors can be eliminated, thereby improving the overall efficiency and ultimately reflecting the modern trend. (5) Next, it is necessary to consider in depth how to select appropriate packaging process methods and packaging machinery types so that one or more materials can be put into the selected packaging materials and packaging containers so that the overall function of the packaging system can be optimized. As far as food sales packaging is concerned, there are two most commonly used and basic packaging process methods today, namely filling and wrapping. The filling method is applicable to almost all materials and types of packaging containers. Specifically, for liquids, powders, and granules with good flowability, packaging can be completed mainly by their own gravity, supplemented by some mechanical action when necessary. However, for semi-fluids with higher viscosity or larger single or combined items, corresponding forced measures such as squeezing, pushing, and picking are required. Wrapping methods differ somewhat; they are mainly suitable for single or combined items with regular shapes, sufficient rigidity, and requiring tight packaging. Flexible plastics and their composite materials (sometimes with added lightweight pallets or liners) are often used, with mechanical action used for wrapping. To date, wrapping forms are diverse, but bag-type wrapping remains the mainstream. Inspired by observations of domestic and international markets, while filling and wrapping methods each have their own characteristics and wide applicability, the former is used more extensively and in larger quantities worldwide, playing a dominant role. Nevertheless, it is worth emphasizing that, considering the aforementioned advantages of bags and boxes, combining filling and wrapping methods in a complementary manner would be like adding wings to a tiger, significantly enhancing the overall functionality of food packaging machinery and achieving more effective all-encompassing packaging. 4. Dominant Models of Food Packaging Machinery In the past decade or so, the international packaging industry has placed great emphasis on improving the versatility and multi-functional integration capabilities of packaging machinery and the entire packaging system, providing timely and flexible production means to meet the ever-changing and diverse needs of the market. Simultaneously, based on the practical needs of rationally simplifying packaging and optimizing packaging processes, continuous exploration has significantly accelerated the pace of technological innovation. This is especially evident in its alignment with the development of modern automatic machine tools. To establish a diversified, universal, and multi-functional integrated packaging machinery system, the major issues of modularization and mechatronics must first be seriously addressed; this is undoubtedly the direction for future development. The significance of mechatronics has been elaborated in detail above and will be omitted here. Only a few points need further elaboration on the issue of modularization: ① The basic guiding principle of modularization is to design a series of modules (generally referring to parts, components, devices, and equipment) with independent functions according to the overall packaging requirements. In application, the system's process and overall function are changed by altering the type, quantity, and position of these modules, making it a flexible, universal packaging machine that achieves multiple functions with a single machine, enabling the packaging of various varieties and small batches of products with less investment. ② From the perspective of the entire machine, horizontal layout is often superior to vertical layout. The former facilitates the extension of modules, thereby increasing functionality, facilitating operation, improving appearance, and stabilizing the machine body. The main disadvantage is the larger footprint. Weighing the pros and cons, the mainstream development trend in the future should be horizontally modular multi-functional packaging machines. Based on the analysis and arguments presented in the preceding sections, and considering both the present and future, we can confirm that the following three types of packaging machines are excellent choices for food sales packaging, and can be considered leading models with a long history of development and strong vitality: vertical bag (box) forming, filling, and sealing machines; horizontal bag (box) forming, filling, and sealing machines; and horizontal seam wrapping machines. Analyzing them according to the concept of group technology, these three types share many commonalities and similarities, which facilitates unified development; however, they also have their own unique characteristics and differences, requiring selection based on local conditions. After comprehensive comparison, their main characteristics are listed below: Packaging Objects—Combining the three types allows for packaging almost anything (except typically gaseous and liquid materials), although the third type has limitations. Packaging Materials—All primarily use roll-type composite films; in some cases, the second type can accommodate straws, and the third type can accommodate trays and other accessories. Packaging Formats – The second type offers a wider variety, including three-side seal bags, four-side seal bags, double-sided bags, stand-up pouches, brick-shaped boxes, and roof-shaped boxes; the first type is next; the third type is less common, typically using pillow-shaped bags, though some can be made into cylindrical bags or four-side seal bags. Packaging Sizes – The first type has a minimum bag width of 10 mm, and the bag length can be infinitely adjusted within a limited range; the latter two types also have infinitely adjustable bag width and length within a limited range, with the third type reaching lengths of over half a meter. Sealing Types – The second type has seen many newly developed sealing methods, such as flat seals with tear lines or upper edges, combination seals with embedded box strips, and screw caps placed in different locations; the other two types are relatively limited. Conveying Motion – Both continuous and stepping motion can be achieved. Structural Combinations – Fully embodying a modular structure, especially the second horizontal layout which facilitates the configuration of functional modules (such as vacuuming and nitrogen filling), coupled with a high degree of mechatronics integration, enhances versatility, versatility, and multi-functional integration, resulting in a series of products. Reports indicate that these three typical machine types have long held a significant position in domestic and international markets, with promising prospects, the second type being the most prominent and still in its early stages of development. Furthermore, it should be noted that aseptic packaging technology is being rapidly adopted in the fields of liquid beverages and liquid by-products. In the future, some foods with high viscosity, mixed granules and liquids, and solid foods will gradually adopt aseptic packaging. It is conceivable that at that time, various bags and boxes made of plastic composite materials will still be effective packaging containers supporting their continued development. Moreover, the various types of aseptic packaging machines already developed, whether vertical or horizontal, are largely derived from and evolved from the aforementioned leading models, only with more complete functions and more complex technology. It is quite clear that aseptic packaging machines will become one of the most representative and dominant types of food packaging machinery. History fully demonstrates that the development of science and technology generally progresses from nothing to something, from simple to complex, and then from complex to a more advanced simplicity, in a continuous cycle without end. Today, there is no such thing as a "universal machine," and the numerous existing packaging machines each have their own specific uses and complement each other, requiring coordinated planning. Even the few specialized machines (such as complete sets of beer and soft drink bottling equipment) still have specific applications and require further refinement. Faced with such a contradictory world of packaging, the purpose of this article is to use the principal contradiction and its key aspects as a breakthrough point. By focusing on the analysis of packaging materials, container structures, processes, and machinery used in food sales packaging, and examining their interrelationships and constraints, this article aims to identify the general direction of development in this important field and the main aspects currently playing a leading role. This will help to optimize the overall situation by focusing on key areas and driving general improvements based on the actual needs of the food packaging system. Therefore, it is not difficult to expect that my country's entire packaging industry and related science and technology education will move forward rapidly, in a coordinated and steady manner, and keep pace with other developed countries, striving to enter the ranks of the world's major packaging powers as soon as possible.