Manufacturing is an important pillar of modern national economy and comprehensive national strength, and its gross domestic product generally accounts for 20% to 55% of a country's gross domestic product. In the composition of enterprise productivity in a country, manufacturing technology generally accounts for about 60%. Experts believe that the competition between the economies of various countries in the world is mainly a competition of manufacturing technology. Its competitiveness is ultimately reflected in the market share of the products it produces. With the rapid development of economic technology and the continuous changes in customer demand and market environment, this competition is becoming increasingly fierce. Therefore, governments of all countries attach great importance to the research of advanced manufacturing technology. 1 Current problems to be solved by manufacturing science The current problems to be solved by manufacturing science are mainly concentrated in the following aspects: (1) The manufacturing system is a complex large system. In order to meet the manufacturing system's agility, rapid response and rapid reorganization capabilities, it is necessary to draw on the research results of multiple disciplines such as information science, life science and social science to explore new system architecture, manufacturing mode and effective operation mechanism of manufacturing system. The optimized organizational structure and good operation of the manufacturing system are the main goals of manufacturing system modeling, simulation and optimization. The new architecture of manufacturing systems is not only important for the agility, responsiveness to demand, and reconfigurability of manufacturing enterprises, but also places higher demands on the flexibility and dynamic reconfigurability of the underlying production equipment of manufacturing enterprises. The concept of biomanufacturing is increasingly being introduced into manufacturing systems to meet the new requirements of manufacturing systems. (2) To support rapid and agile manufacturing, the sharing of geometric knowledge has become a key issue restricting product development and manufacturing in modern manufacturing technology. For example, in computer-aided design and manufacturing (CAD/CAM) integration, coordinate measurement (CMM) and robotics, there are a large number of geometric algorithm design and analysis problems in three-dimensional real space, especially geometric representation, geometric calculation and geometric reasoning problems; in measurement and robot path planning and part positioning (such as localization), there are geometric calculation and geometric reasoning problems in C-space (configuration space); in the description of object operations (clamping, grasping and assembly, etc.) and robot multi-finger grasping planning, assembly motion planning and operation planning, geometric reasoning needs to be performed in screw space. The geometrical study of physical and mechanical phenomena in the manufacturing process has formed a number of research topics in manufacturing science, such as geometric calculation and geometric reasoning. Its theory needs further breakthroughs. Currently, a new discipline, computer geometry, is receiving increasingly widespread and in-depth research. (3) In the modern manufacturing process, information has not only become the decisive factor that dominates the manufacturing industry, but also the most active driving factor. Improving the information processing capability of the manufacturing system has become a key point in the development of modern manufacturing science. Due to the multi-level nature of the information organization and structure of the manufacturing system, the acquisition, integration and fusion of manufacturing information presents a three-dimensional nature, a multi-dimensional nature of information measurement, and a multi-level nature of information organization. Further breakthroughs are needed in the structural model of manufacturing information, the consistency constraint of manufacturing information, the propagation and processing, and the management of the manufacturing knowledge base of massive data. (4) The widespread application of various artificial intelligence tools and computational intelligence methods in manufacturing has promoted the development of manufacturing intelligence. A type of computational intelligence tool based on biological evolution algorithm has received increasing attention in the field of combinatorial optimization solution technology, including scheduling problems. It is expected to break through the constraints of problem size in both the solution speed and solution accuracy when solving combinatorial optimization problems in manufacturing. Manufacturing intelligence is also manifested in many aspects, including intelligent scheduling, intelligent design, intelligent processing, robotics, intelligent control, intelligent process planning, and intelligent diagnostics. These issues are key theoretical problems in current product innovation and fundamental issues that elevate manufacturing from a craft to a science. Breakthroughs in these key areas can form a basic research system for product innovation. 2. Frontier Science of Modern Mechanical Engineering The cross-fertilization of different sciences will generate new scientific clusters. Economic development and social progress have created new requirements and expectations for science and technology, thus forming frontier science. Frontier science is the boundary between solved and unsolved scientific problems. Frontier science has distinct temporal, domain, and dynamic characteristics. A key feature distinguishing engineering frontier science from general basic science is that it encompasses key scientific and technological problems arising in engineering practice. Extensive research has been conducted both domestically and internationally in fields such as ultrasonic motors, ultra-high-speed cutting, and green design and manufacturing, but the key to innovation lies in the fact that the mechanical science problems remain unclear. While significant research has been conducted both domestically and internationally in areas such as performance optimization design and product innovation design of large and complex mechanical systems, intelligent structures and systems, intelligent robots and their dynamics, nanotribology, three-dimensional numerical simulation and physical simulation of manufacturing processes, key technological foundations for ultra-precision and micro-machining, design and manufacturing foundations for large and ultra-large precision instruments and equipment, virtual manufacturing and virtual instruments, nano-measurement and instruments, parallel shaft machine tools, and microelectromechanical systems, many key scientific and technological problems remain to be solved. Information science, nanoscience, materials science, life science, management science, and manufacturing science will be the mainstream sciences that will change the 21st century, and the resulting high technologies and industries will transform the world. Therefore, manufacturing systems and manufacturing informatics, nanomechanics and nanomanufacturing science, biomimetic mechanics and biomimetic manufacturing, manufacturing management science, and reconfigurable manufacturing systems, which intersect with the above fields, will be important frontiers in mechanical engineering in the 21st century. 2.1 The Intersection of Manufacturing Science and Information Science—Manufacturing Information Science Electromechanical products are the materialization of information on raw materials. The added value of many modern products is mainly reflected in information. Therefore, the acquisition and application of information in the manufacturing process is crucial. Information technology is an important indicator of the globalization and modernization of manufacturing science and technology. On the one hand, people are beginning to explore the informational nature of product design and manufacturing processes, and on the other hand, they are modifying manufacturing technology itself to adapt to the new information-based manufacturing environment. With a deeper understanding of manufacturing processes and systems, researchers are trying to describe and express them with new concepts and methods to further achieve the goal of control and optimization. The information related to manufacturing mainly includes product information, process information and management information. The main research directions and contents in this field are as follows: (1) Acquisition, processing, storage, transmission and application of manufacturing information, and the transformation of a large amount of manufacturing information into knowledge and decision-making. (2) Expression of non-symbolic information, fidelity transmission of manufacturing information, management of manufacturing information, production decision-making under incomplete manufacturing information conditions, virtual management manufacturing, design and manufacturing in a network environment, and control science problems in manufacturing processes and systems. These contents are the product of the integration of manufacturing science and information science, constituting a new branch of manufacturing science—manufacturing informatics. 2.2 Micromechanical and its manufacturing technology research Micro-electromechanical systems (MEMS) refer to complete micro-electromechanical systems that integrate micro-sensors, micro-actuators, signal processing and control circuits, interface circuits, communication and power supply. The goal of MEMS technology is to explore components and systems with new principles and functions through system miniaturization and integration. The development of MEMS will greatly promote the miniaturization and micro-computing of various products, increase the functional density, information density and interconnection density of devices and systems by orders of magnitude, and significantly save energy and materials. It can not only reduce the cost of electromechanical systems, but also accomplish many tasks that large-size electromechanical systems cannot. For example, a red blood cell can be picked up with micro tweezers with a tip diameter of 5μm; a 3mm-sized car can be manufactured that can move; and an airplane the size of a butterfly that can fly in a magnetic field, etc. The development of MEMS technology has opened up entirely new fields and industries, possessing many advantages unmatched by traditional sensors. Therefore, it has a very broad application prospect in manufacturing, aviation, aerospace, transportation, communications, agriculture, biomedicine, environmental monitoring, military, home, and almost every field people encounter. Micromechanics is a product of the fusion of mechanical and electronic technologies at the nanoscale. As early as 1959, scientists proposed the concept of micromechanics, and in 1962, the first silicon micro pressure sensor was developed. In 1987, the University of California, Berkeley developed a silicon micro electrostatic motor with a rotor diameter of 60–120 μm, demonstrating the potential to fabricate tiny movable structures using silicon micromachining processes and manufacture micro-systems compatible with integrated circuits. Micromechanical technology has the potential to have a significant impact on global science and technology, economic development, and national defense in the 21st century, much like microelectronics technology in the 20th century. The development of micromechanics in the past decade has been remarkable. Its characteristics are as follows: A considerable number of micro-components (microstructures, micro-sensors, and micro-actuators, etc.) and microsystems have been successfully researched, demonstrating their practical and potential application value; the development of various micro-manufacturing technologies, especially semiconductor microfabrication, has become a supporting technology for microsystems; the research of microelectromechanical systems (MEMS) requires a multidisciplinary research team. MEMS technology is a cutting-edge research field developed on the basis of microelectronics processes, involving multiple engineering technologies and sciences such as electronic engineering, mechanical engineering, materials engineering, physics, chemistry, and biomedicine. Currently, there is still a lack of sufficient understanding of the motion laws of mechanical systems under microscopic conditions, the physical characteristics of micro-components, and the mechanical behavior under load. A microsystem design theory and method based on a certain theoretical foundation has not yet been formed, therefore research can only be conducted through experience and trial and error. Key scientific problems in micromechanical system research include the scale effect, physical characteristics, and biochemical characteristics of microsystems. Microsystem research is on the eve of a breakthrough and is an area urgently needing in-depth research. 2.3 Material Preparation/Part Manufacturing Integration and New Processing Technologies: Basic materials are a milestone in human progress and the foundation of manufacturing and high-tech development. The successful preparation and application of every important new material advances material civilization and enhances national economic and military strength. In the mid-21st century, the world will shift from a resource-intensive industrial economy to a knowledge-based economy, demanding high performance, functionalization, and intelligence in materials and components; requiring quantitative and digital design of materials and components; and demanding rapid, efficient, and integrated preparation of materials and components. Digital design and simulation optimization of materials and components are key to achieving efficient and high-quality preparation/manufacturing of materials and components, as well as integrated manufacturing. On the one hand, computer-aided simulation optimization can reduce experimental steps in material preparation and component manufacturing, obtaining optimal process solutions and achieving efficient and high-quality preparation/manufacturing of materials and components. On the other hand, based on the requirements of different material properties, such as elastic modulus, coefficient of thermal expansion, and electromagnetic properties, the design forms of materials and components can be studied. Furthermore, combining traditional material removal manufacturing techniques and material coating techniques, composite forming processes using multiple material components can be studied. Theories, technologies, and methods for the digital manufacturing of materials and parts, such as rapid prototyping technology, utilize the principle of gradual material growth, breaking through many limitations of traditional material removal and deformation machining. This process requires no tools or molds and can rapidly manufacture arbitrarily complex three-dimensional solid models or parts with specific functions. 2.4 Mechanical Biomimetic Manufacturing: The 21st century will be the century of life sciences. The deep integration of mechanical science and life sciences will generate entirely new product concepts (such as intelligent biomimetic structures), develop new processes (such as growth molding processes), and open up a series of new industries, providing new solutions to a series of problems in product design, manufacturing processes, and systems. This is a highly innovative and challenging frontier field. The excellent qualities accumulated by organisms on Earth during their long evolution provide examples and guidelines for solving various problems in human manufacturing activities. Learning methods and techniques for organizing and operating complex systems from life phenomena is an effective way to solve many of the current challenges facing the manufacturing industry. Biomimetic manufacturing refers to a manufacturing system and process that imitates the self-organization, self-healing, self-growth, and self-evolutionary functional structures and operating modes of biological organs. If the mechanization and automation of manufacturing processes have extended human physical strength, and intelligentization has extended human intelligence, then "bionic manufacturing" can be said to extend the organizational structure and evolutionary process of humanity itself. The scientific issues involved in bionic manufacturing are the "self-organization" mechanisms of organisms and their application in manufacturing systems. "Self-organization" refers to the process by which a system, driven by its internal mechanisms, continuously improves its organizational structure and operational mode, thereby enhancing its adaptability to the environment. The "self-organization" mechanism of bionic manufacturing provides the theoretical basis and conditions for bottom-up parallel product design, automatic generation of manufacturing process specifications, dynamic reorganization of production systems, and automatic optimization of products and manufacturing systems. Bionic manufacturing represents a "distant hybridization" of manufacturing science and life science, and it will have a profound impact on the manufacturing industry of the 21st century. The research content of biomimetic manufacturing currently has two aspects: 2.4.1 Biomimetic manufacturing oriented towards life studies the general laws and models of life phenomena, such as artificial life, cellular automata, biological information processing techniques, biological intelligence, the organizational structure and operation mode of biotypes, and the evolutionary and optimization mechanisms of organisms; 2.4.2 Biomimetic manufacturing oriented towards manufacturing studies the self-organizing mechanisms and methods of biomimetic manufacturing systems, such as: biomimetic design principles based on full information sharing, distributed control based on multi-autonomous unit collaboration, and optimization strategies based on evolutionary mechanisms; and studies the conceptual system and foundation of biomimetic manufacturing, such as: formal description of biomimetic space and its information mapping relationship, and methods for measuring the complexity of biomimetic systems and their evolutionary processes. Mechanical biomimetic and biomimetic manufacturing represent a high degree of integration between mechanical science and life sciences, information science, materials science, and other disciplines. Its research content includes growth forming processes, biomimetic design and manufacturing systems, intelligent biomimetic machinery, and bio-forming manufacturing. Most of the current research work is cutting-edge exploratory work with distinct characteristics of basic research. If the opportunity is seized and research continues, revolutionary breakthroughs may be achieved. Future research areas to focus on include bioprocessing technology, biomimetic manufacturing systems, tissue engineering based on rapid prototyping technology, and key technology foundations related to bioengineering. 3. Development Trends of Modern Manufacturing Technology Since the 1990s, countries around the world have prioritized the research and development of manufacturing technology as a key national technology, such as the Advanced Manufacturing Technology Program (AMTP) in the United States, the International Cooperation Program on Intelligent Manufacturing Technology (IMS) in Japan, the National Advanced Modern Technology Program (G-7) in South Korea, the Manufacturing 2000 program in Germany, and the ESPRIT and BRITE-EURAM programs of the European Community. With the continuous development of high-tech such as electronics and information, and the personalization and diversification of market demand, the general trend of future development of modern manufacturing technology is towards precision, flexibility, networking, virtualization, intelligence, green integration, and globalization. The current development trends of modern manufacturing technology can be roughly summarized in the following nine aspects: (1) Information technology, management technology and process technology are closely integrated, and modern manufacturing production models will continue to develop. (2) Design technology and methods are becoming more modern. (3) Molding and manufacturing technologies are becoming more precise, and manufacturing processes are achieving low energy consumption. (4) The formation of new special processing methods. (5) The development of a new generation of ultra-precision and ultra-high-speed manufacturing equipment. (6) The development of processing technology from skills to engineering science. (7) The implementation of pollution-free green manufacturing. (8) The widespread application of virtual reality technology in the manufacturing industry. (9) Human-centered manufacturing.