Investment casting, also known as lost wax casting, is commonly used in precision gravity casting: select appropriate investment materials (such as paraffin) to make investment mold; repeatedly immerse refractory coating on the investment mold, sprinkle refractory sand, make the mold shell harden and dry, then melt the internal investment mold to obtain the mold cavity; bake the mold shell to obtain enough strength, burn off the remaining investment mold materials; casting needs to solidify and cool the metal materials, After shelling, desanding will be carried out to obtain high-precision finished products. Heat treatment, cold processing and surface treatment will be carried out according to the needs of the products.

Sand casting and mass production factories should create conditions. The production line of old-fashioned shaker or shaker molding machine with advanced molding and core making methods is not high enough, the labor intensity of workers is high, the noise is high, and it is not suitable for the requirements of mass production. Small castings should be transformed step by step The horizontal or vertical high-pressure molding machine production line has high production efficiency and small floor area. For medium-sized castings, various high-pressure molding machine production lines with box body and air impact molding lines can be selected. To meet the requirements of fast and high-precision molding production lines, the core making method can be selected as: high-efficiency manufacturing of cold core box, hot core box, shell core and other core methods.

Resin self hardening sand molding and core making can be considered for large and medium castings.For large castings in small batch production, manual modeling is still an important method. Manual modeling is flexible to meet various complex requirements and does not need many process equipment. Water glass sand mold, VRH water glass sand mold, organic ester water glass self hardening sand mold, clay dry sand mold, resin self hardening sand mold and cement sand mold can be used; for large castings produced by a single piece, the pit mold method has low production cost, fast production speed, and for mass production or long-term production of finalized products, it is more suitable for multi box and sub box molding although the investment of mold and sand box is high, But it can be compensated from the aspects of saving forming time and improving product quality.

Low pressure casting, die casting, centrifugal casting and other casting methods are only suitable for mass production due to the high price of equipment and mold.

For example, it is also used to produce large-scale machine tools and other castings. In general, the core making method is used instead of mold making and sand box in other factories. Enterprises with different patterns made by sand box forming method have different production conditions (including equipment, site, staff quality, etc.), production habits and accumulated experience. According to these conditions, we should consider which products are suitable and which ones are produced The product is not suitable.

Different casting methods have different precision, different initial investment and productivity, and different final economic benefits. Therefore, in order to achieve more, faster, better and less, it is necessary to comprehensively consider all aspects of the selected casting methods for preliminary cost estimation, so as to determine the casting methods with high economic benefits and ensure the casting requirements.

Although the development of China’s foundry industry is in a relatively difficult period, in the long run, there is still some hope for the development of China’s precision casting industry, the market demand has begun to pick up slowly, and with the strong strength of China’s foundry industry development, I believe that China’s foundry industry will make gratifying achievements.

Experts said that in order to fundamentally improve the level of casting technology, we must do the following four points:

1、 It is to develop simulation technology, improve prediction accuracy, strengthen process control, improve the grasp of production regularity, which affects the output of batch production.

2、 It is the combination of production, learning and research that enterprises should not only enhance their innovation awareness and R & D ability, but also attach importance to and strengthen the combination of production, learning and research, which is mainly based on precision casting enterprises.

3、 It is the basis of industry to attach importance to material research and development. At present, there is still a lot of work to be done. In the field of Aeronautics and Astronautics, the research and smelting technology of alloy materials, especially superalloys, need to be improved, and there is a big gap with foreign countries.

4、 Therefore, the research and development of precision casting equipment is still a hot spot.