Casting is the fundamental manufacturing industry, the development of the foundry industry is a key part of the national strategy. The state attaches great importance to the development and layout of the foundry industry, "14th Five-Year Plan" plan clearly to digital transformation and development goals: by 2025, the use of 3D printing technology to produce more than 500,000 tons of castings; the realization of the demonstration of inorganic binder and other green molding materials; foundry sand recycling to reach more than 8 million tons of recycling; Cultivate more than 200 green casting factories. In April this year, the three ministries and commissions of the joint release also proposed to promote the integration of die casting forming, moldless casting, sand 3D printing and other advanced process technologies to achieve industrialization and application.

As the world's first casting country, China's casting industry has a market size of about 400 billion, accounting for 45% globally; there are more than 24,000 foundries, with a total output of 51.7 million tons of castings in 2022, which maintains a steady growth. But at the same time there are problems of overcapacity, high energy consumption, high pollution, not strong, not refined, energy saving and emission reduction pressure, shortage of skilled workers, weak independent innovation, and serious homogenization competition. According to statistics, the national casting annual output of more than 10,000 tons of casting enterprises more than 1,000, more than 50,000 tons of nearly 200 enterprises. Head of more than 2,000 casting production accounted for more than 55% of the total national capacity. The head of the lack of customization or small batch trial production capacity, the development of new products is slow, high cost; "long tail" low capacity utilization, most of them to be eliminated; only the "long tail" in the head of the enterprise, relying on 3D printing and automation rate increased after Only the head of the "long tail" enterprises, after relying on 3D printing and automation rate increase, can survive, and there may be several times the concentration of the space.
Driven by policy, market and technology, 3DP sand printing technology has emerged. 3DP sand printing technology is a digital green manufacturing technology based on digital model files, using powdered metal or non-metallic and other adhesive materials, layer by layer printing to construct objects. Compared with traditional sand casting, 3DP sand printing technology does not require molds, direct printing sand, design flexibility, can be low-cost, efficiently complete the development of new products and small and medium-volume product delivery, rapid response to market demand. In terms of quality, 3DP sand mold is not subject to the constraints of the mold sand turning process, with micron-level high precision, complex structure of one free-form, part of the cast aluminum casting surface accuracy can be comparable to precision casting, but also reduces the assembly error caused by the scrap rate, reducing the labor of workers.

At present, 3DP sand printing technology has been matured in the casting production of commercialized applications, is a real market-proven universal technology. Its optimization of sand performance, processing speed, molding size, etc. to enhance the obvious advantages, especially for new product development, complex products and small batch production. Some of the introduction of 3DP sand printing equipment for intelligent transformation of foundry enterprises, has established a green, flexible, high-end rapid casting capabilities, to achieve production efficiency, capacity, revenue doubling growth. Some enterprises have even experienced oversupply and overflow of orders due to the obvious improvement of technology and services.

Figure: Green fast casting factory that has maturely applied 3DP sand printing technology In the face of 3DP sand printing equipment of various brands on the market, price, performance, stability, use and maintenance costs are usually the factors that users will consider when purchasing. Ltd., a 3D printing equipment and rapid manufacturing service provider, independently developed a production flagship product - Longyuan molding 3DP sand printing equipment AFS-J1600Pro, once the market is widely favored by the market, has been purchased by a number of foundry users for the production line, by virtue of the excellent molding accuracy, balanced and controlled casting technology. With excellent molding accuracy, balanced and controllable casting performance and excellent reliability, it has helped users to solve the contradiction between efficiency, strength and casting performance in casting production, and completed tens of millions of orders.

It is understood that the equipment molding cylinder size of 1600 × 800 × 600mm, using the latest generation of high stability, low noise, high-speed vibration powder laying technology and 2-Pass high-precision printing technology, with high-performance molding process and intelligent algorithms technology, can achieve 15 seconds per layer of the printing speed and the highest ± 0.3mm of the printing accuracy; print the tensile strength of the sand type can reach up to 2.5 MPa. The tensile strength of the printed sand mold can be up to 2.5MPa, air generation 8-11ml/g, and the surface roughness ≤ Ra25. The equipment adopts modular design, which is convenient and flexible for maintenance, with low maintenance cost; equipped with intelligent system, which makes the operation easier, and realizes one-button printing with the function of printing early warning prompts; it can also realize the real-time monitoring and record traceability of the whole process through the visual monitoring and other intelligent systems. For cast aluminum, cast iron, cast steel, cast magnesium and other different casting applications, to provide open source sand process solutions, supporting a wealth of sand systems and high-performance binder, curing agent, cleaning agent, to optimize the cost of use for users.

A user uses AFS-J1600Pro sand rapid casting process to produce a lightweight frame for a new energy vehicle company, and the finished aluminum alloy (ZL101) castings were delivered in 6 days. The dimensional accuracy of the finished product reaches CT7, the surface roughness is better than Ra12.5, and the casting surface is free of porosity and cracks, with complete shape and clear structure. Compared with the 40-day production cycle required by the traditional manufacturing process, the production cycle was shortened by 85% and the cost was reduced by 32% by using 3DP sand-printed rapid casting.

A user through the AFS-J1600Pro sand rapid casting process for a car factory trial production of engine block, due to the complexity of the cylinder structure, and small wall thickness, if the traditional method of production cycle takes more than 1 month. 3DP sand printing equipment produced by the sand mold, precision and strength than the traditional process have been greatly improved, the tensile strength of up to 2MPa, the casting surface roughness of better than Ra12.5, defect control is good, no flesh, pores, cracks, slag, no surface defects and defects. It only took 10 days to deliver the finished castings of gray cast iron (HT250), shortening the production cycle by 2/3 and reducing the cost by 30%.
"Fourteen-Five" is China's economic restructuring, industrial restructuring and upgrading of an important stage, but also an important period of accelerated development of China's foundry industry. Some foundry enterprises are still due to high energy consumption, high pollution, product precision does not meet the requirements, recruitment difficulties and other issues and troubled, deep in the capital, technology, orders in the cycle of the circle of uncertainty and confusion. It is recommended that these business operators should be early out of the inherent thinking, in a deep understanding and comprehension of the national policy on the basis of the initiative to seek change, change the way of thinking and development, through technology, process transformation and upgrading, take the green, intelligent, high-end road of sustainable development, in order to seize the opportunity to break out of the predicament.