What are the stages in the development of mechanical design technology?

Design is an activity in which people produce information that satisfies requirements based on predetermined goals. Information is expressed in the form of graphics, text, data, symbols and so on. Technology is the means used by human beings to transform the world, and is the unity of human factors (knowledge, ability) and materialized factors (tools, equipment). Design technology refers to the operational procedures, methods and skills formed by engaging in design activities, as well as the tools and equipment used. According to the characteristics of design technology, the development of mechanical design technology can be divided into five stages:

(1) intuitive design (ancient times-1500 years). Since mankind began to manufacture tools, design activities have existed. In ancient times, design technology and manufacturing technology were embodied in the same individual craftsman (Figure 4-3). They designed and made products either by inspiration from natural phenomena or by intuitive senses acquired through long labor.

(2) Empirical Design (1501-1849). Craftsmen began to use the principles of mechanics to form a variety of devices, simple tools gradually to the traditional mechanical development. the first industrial revolution in the mid-18th century, so that the mechanical technology appeared in the design and manufacture of the division of labor. the beginning of the 19th century, mechanics from the mechanics of the independence of the late 19th century, mechanical engineering is gradually becoming an independent discipline. Mechanics is the theoretical basis of mechanical engineering. Because the mechanical manufacturing at that time has not yet formed a discipline system, so mechanics can be used as a short form of mechanical engineering. At that time, the design technology was mainly embodied in the basic mechanism and basic parts studied in mechanics. The design mainly relies on the designer's personal talent and experience, and its limitations and arbitrariness are great, as shown in Figure 4-4.

Figure 4-3 Craftsman in design

Figure 4-4 Early loom (3) Semi-empirical design (1850-1949).After the first World's Fair in 1851, a large number of complex mechanical products appeared, as shown in Fig. 4-5.In the mid-nineteenth century, the second industrial revolution took place, which led to a significant increase in both the theoretical and the practical aspects of the design technology. both theoretically and practically. The publication of Theoretical Kinematics in Germany showed that people's understanding of design had risen for the first time from characteristics to individuality. the drawing design method appeared at the beginning of the 20th century, which led to a significant reduction in costs. standardization began to move in an organized manner at the beginning of the 20th century, which improved the efficiency and quality of design, as shown in Fig. 4-6. People reduced the blindness of design through the testing of key zeros and components and research on the quality of design of various specialized products. However, the design itself has not been studied as a discipline at this stage, and the design is still largely empirical and limited.

Figure 4-5 Katsuya sewing machine designed in 1870

Figure 4-6 Austin car (4) Semi-automatic design (1950-1989). The distinguishing feature of this stage is the innovation of design tools and in-depth study of design methods. 1950s electronic computers used in scientific computing, 1960s appeared computerized automatic drawing, the United States launched CAD system in 1970, 1971, Japan published the "Design Engineering Series", 1977, Germany published the "Design", which shows that people's understanding of design once again from the In the 1980s, the computer automated information processing, designers are mainly engaged in decision-making, and often require group cooperation to complete the design, such as Figure 4-7 shown in the car and tractor is designed and engineers **** with the completion. This stage gradually formed the mechanical design engineering.

Figure 4-7 Rowe designed machinery (5) automated design (1990 to the present). 1990s, the formation of the decision-making automation based on computer integrated manufacturing systems (CIMS). Decision automation is essentially the automation of knowledge processing and use. At this stage, a large number of general decisions and information processing in the design process can be done by computers, and the designer can make only critical decisions. The Boeing 777 airplane designed using virtual reality technology, shown in Figure 4-8, is the world's first airplane to lift off without drawings or prototypes.

Figure 4-8 The Boeing 777 airplane manufacturing process