Casting is a very ancient metal forming method. Thousands of years ago, ancient craftsmen used simple tools, adopted original technology and made exquisite castings with exquisite skills. Today, although there are many advanced casting processes, and the degree of mechanization and automation is far from comparable in the past, the casting production (especially in developing countries such as China) is still the coexistence of backward technology and advanced technology, and the phenomenon of “multi-level technology coexistence” is very significant, Many castings can be cast in different grades with great differences in technical content.
Generally, the index system describing the level of industrial technology can be expressed by technical level, technical equipment level and structural technology. Therefore, the foundry industry technology can be expressed by the ternary coordinate model in the figure below.
According to the technical level index, casting technology can be divided into five levels: cutting-edge technology, advanced technology, medium technology, primary technology and original technology. According to the degree of technical equipment, it can be divided into five levels: automation, semi automation, mechanization, semi mechanization and manual tools. Internationally, the above five levels are usually subdivided into 17 levels. China’s casting production is mostly in the stage of semi mechanization to semi automation, but there are also many original manual operations (especially in small township enterprises and core making, pouring and cleaning processes). Structural technology represents the scope and development degree of technical principles, technical means, process methods, processing objects, technical operation and production organization. The differences of different industries / industries are reflected in the differences of structural technology. With the gradual upgrading of technical level and technical equipment, its scope will continue to expand and its level will continue to improve. According to the different combinations of the three technical indexes, they can be combined into many different levels of casting technology, and there are many alternative technologies to be developed. When selecting technology, we should consider its advanced nature and applicability at the same time.
A few foundry enterprises in China have successfully applied advanced technology and adopted mechanized and semi-automatic production means, which are close to or reach the world level in alloy, process and production organization, but a large number of enterprises still use backward technology to produce in varying degrees. The coexistence of multi-level technology is not only the technical basis for the existence of a large number of small and medium-sized township foundry enterprises, but also the technical root of scattered and chaotic foundry industry.