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The most commonly used method in precision casting is investment casting, also known as lost wax casting: selecting suitable investment materials (such as paraffin) to make the investment mold; Repeatedly apply refractory coating and sprinkle refractory sand on the investment mold, harden the shell and dry it; Dissolve the internal mold again to obtain the mold cavity; Roast the shell to obtain sufficient strength and burn off residual investment material,; Metal materials required for pouring; Solidification cooling, sand removal after shelling, thus obtaining high-precision finished products. According to product requirements, perform heat treatment, cold processing, and surface treatment. For example, in sand casting, factories producing in large quantities should create conditions to adopt technologically advanced molding and core making methods. The productivity of old-fashioned shock-absorbing or shock-absorbing molding machine production lines is not high enough, the labor intensity of workers is high, the noise is loud, and they are not suitable for the requirements of large-scale production. Therefore, they should be gradually transformed. For small castings, a boxless high-pressure molding machine production line with horizontal or vertical parting can be used. The production efficiency of solid molding is high and the footprint is small; For intermediate parts, various high-pressure molding machine production lines and air impact molding lines can be used to meet the requirements of fast and high-precision molding production lines. Core making methods can be selected, such as cold core box, hot core box, shell core and other efficient core making methods.

For medium batch large castings, resin self hardening sand molding and core making can be considered.

For heavy castings produced in small batches, manual molding is still an important method. Manual molding can adapt to various complex requirements and is relatively flexible, without requiring a lot of process equipment. It can be applied to water glass sand molds, VRH water glass sand molds, organic ester water glass self hardening sand molds, clay dry molds, resin self hardening sand molds, and cement sand molds; For heavy castings produced in a single piece, the pit forming method has low cost and fast production. It is more suitable to use multi box molding and split box molding methods for mass production or long-term production of standardized products. Although the investment in molds, sandboxes, etc. is initially high, it can be compensated by saving molding 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 expensive equipment and molds.

The conditional method should be suitable

For example, for the production of large machine tool bed frames and other castings, the core forming method is generally used, without making patterns or sandboxes, and core forming is done in the pit; And other factories use the sand box molding method to produce patterns. Different enterprises have different production conditions (including equipment, site, employee quality, etc.), production habits, and accumulated experience. Therefore, it is necessary to consider what products are suitable for production and what products are not suitable (or cannot be) produced based on these conditions.

Accuracy requirements and cost

The precision of castings obtained by various casting methods is different, and the initial investment and productivity are also inconsistent, resulting in differences in the final economic benefits. Therefore, in order to achieve more, faster, better, and more cost-effective, we should take into account all aspects. A preliminary cost estimate should be made for the selected casting method to determine a casting method that is economically efficient and meets the requirements of the casting.

Although the development of China's casting industry is in a relatively difficult period, from a long-term perspective, there is still some hope for the development of China's precision casting industry. Market demand has slowly begun to recover, and coupled with the strong strength of China's casting industry development, it is believed that China's casting industry will achieve remarkable results.

Experts suggest that to fundamentally improve the level of casting technology, the following four points should be achieved: developing simulation technology, improving prediction accuracy, strengthening process control, and increasing yield. The problem of regularity is not well grasped, which affects the yield of finished products in mass production. Secondly, the integration of industry, academia, and research. In addition to enhancing innovation awareness and improving research and development capabilities, the independent innovation of enterprises also needs to pay attention to and strengthen the combination of "production, learning, and research" with precision casting enterprises as the main body. Thirdly, attach importance to material research and development. Materials are the foundation of industry, and there is still a lot of work to be done at present. In the aerospace field, the research and melting technology of alloy materials, especially high-temperature alloys and other new materials, still need to be improved, and there is still a significant gap compared to foreign countries. Fourthly, pay attention to the improvement of equipment technology. The main issue in terms of technology is still equipment, and many key equipment, such as directional solidification equipment, still rely on imports. Therefore, the research and development of precision casting equipment is still a key focus.