Learn more about coated sand process

In the field of metal processing, sand casting is a manufacturing method with a long history and wide application, especially suitable for the production of cast steel and cast iron parts with complex shapes and various sizes. Among them, the coated sand casting process occupies an important position in modern casting production due to its high precision, high efficiency, good disintegration and environmental protection. The following is a detailed introduction to the coated sand production line and its process, which will cover the whole process from raw material preparation to finished product output.

1. Overview of coated sand casting process

The coated sand casting process is a casting method that uses coated sand as a modeling material. Coated sand is made by mixing raw sand, resin, curing agent and other raw materials in a particular proportion. After a specific process, the resin is evenly coated on the surface of the sand particles to form a thin layer of resin film. After heating and curing, this layer of resin film can significantly improve the strength and anti-scouring ability of the sand mold, thereby ensuring the quality and dimensional accuracy of the casting.

2. Main links and characteristics of coated sand production line

The coated sand production line mainly includes key links such as mold making, sand mixing, core shooting, molding, box assembly, pouring, cooling and sand dropping, cleaning and post-processing. Each link has its specific process requirements and characteristics.

Mold making

Process description: According to the design drawings of the casting, use materials such as wood, metal or plastic to make the pattern. High-precision patterns are the basis for ensuring the dimensional accuracy of castings. Modern casting technology often uses CNC machining technology to improve the accuracy and production efficiency of patterns.

Features: The application of CNC machining technology makes pattern-making more accurate and efficient, laying a solid foundation for the subsequent casting process.

Sand mixing

Process description: Add raw sand, resin, curing agent and other raw materials to the sand mixer in proportion, and through the stirring action of the sand mixer, the resin is evenly coated on the surface of the sand particles. Advanced sand mixing equipment can accurately control the amount of each raw material added and the sand mixing time, thereby ensuring the stability of the quality of the coated sand.

Features: The high degree of automation and precise control of the sand mixing process makes the quality of the coated sand more stable and reliable, providing high-quality molding materials for the subsequent casting process.

Core Shooting

Process Description: Use a core shooting machine to shoot coated sand into the core box and heat and solidify it in the core box to form a sand core. The core shooting process requires strict control of parameters such as sand shooting pressure, temperature and time to ensure the dimensional accuracy, surface quality and strength of the sand core.

Features: The high automation and precise control of the core shooting process have significantly improved the production efficiency and quality of the sand core.

Molding

Process Description: Fill the coated sand into the sandbox or special molding equipment and form a mold through operations such as compaction and demolding. The molding process needs to ensure that the compactness of the mold is uniform to prevent defects such as shrinkage and pores in the casting.

Features: The automation and precise control of the molding process make the compactness of the mold more uniform, providing a high-quality mold for the subsequent pouring process.

Mold Closing

Process Description: Put the sand core into the mold cavity, then put the upper and lower sandboxes or the left and right half molds together and fix them with clips, bolts, etc. The closing process needs to ensure that the sand core and the mold are accurately positioned to prevent misalignment during the pouring process.

Features: The precise control of the closing process further ensures the dimensional accuracy of the casting.

Pouring

Process description: Pour the molten metal into the mold cavity. The pouring process requires precise control of the pouring temperature and speed to prevent defects in the casting.

Features: The precise control of the pouring process significantly improves the quality of the casting.

Cooling and sand removal

Process description: The cast casting is cooled naturally or forcedly in the mold after pouring. After cooling, the casting is taken out of the mold, which is the sand removal process.

Features: In the coated sand casting process, the coated sand core and sand mold are easy to collapse, which is convenient for sand removal and cleaning, reducing the cleaning workload and damage to the casting.

Cleaning and post-processing

Process description: Remove sand particles, burrs, flash, etc., on the surface of the casting, and perform shot blasting, grinding and other treatments on the casting to improve the surface quality. Some castings also require post-processing procedures such as heat treatment and machining.

Features: Precise control of the cleaning and post-processing process has significantly improved the surface quality and performance of the castings.

3. Features and advantages of coated sand casting process

The coated sand casting process has an essential position in modern casting production with its unique advantages and characteristics. Its main features and advantages include:

High precision: The coated sand has good fluidity and high strength and can accurately replicate the shape of the pattern and core box so that the casting has high dimensional accuracy and low surface roughness, reducing the subsequent processing allowance.

High efficiency: The core shooting and molding process has a high degree of automation, which significantly improves production efficiency, can quickly form sand cores and castings, shorten production cycles, and is suitable for mass production.

Good collapsibility: After the casting cools, the coated sand core and sand mold are easy to collapse, which is convenient for sand dropping and cleaning, reducing the cleaning workload and damage to the casting.

Strong adaptability: The formula and process parameters of the coated sand can be adjusted according to the requirements of different castings to adapt to the production of castings of various complex shapes and materials, such as iron casting, steel casting, non-ferrous alloys, etc.

Better environmental protection: Compared with some traditional casting processes, coated sand casting produces relatively less dust and harmful gases, and waste-coated sand can be recycled and reused, which is beneficial to environmental protection.

4. Production efficiency and specifications of coated sand production line

The production efficiency and specifications of coated sand production line vary depending on factors such as equipment type, degree of automation and technical level. Generally speaking, the efficiency of semi-automatic production lines is relatively low, while the efficiency of fully automatic production lines is higher. The following are some standard specifications and efficiency of coated sand production lines:

Semi-automatic production line: The efficiency of semi-automatic production lines with manual feeding is relatively low, and the output per hour is generally around 2-3 tons. This production line is suitable for small-scale production or trial production stages.

Fully automatic production line: The computer-controlled fully automatic production line has higher efficiency. For example, the fully automatic coated sand production line uses gas flame direct injection, 300 type one-time feeding 300Kg, each production furnace takes 3.5min, and the output per hour can reach about 5 tons. This production line is suitable for large-scale batch production, which can significantly improve production efficiency and reduce costs.

In addition, there are many options for heating methods of coated sand production lines, such as gas, electricity, liquefied gas, bioparticles, etc. Different heating methods are suitable for various production environments and needs. At the same time, the processing capacity of the production line is also different. For example, the processing capacity of the thermal regeneration production line is generally between 1.5-2.0t/h.

5. Application and development of coated sand casting process

Due to its unique advantages and characteristics, the coated sand casting process has been widely used in automobile manufacturing, machinery manufacturing, aerospace and other fields. Especially in the field of automobile manufacturing, the coated sand casting process is commonly used in the production of key castings such as engine cylinder blocks, cylinder heads, crankshafts, etc. These castings have extremely high requirements for dimensional accuracy and surface quality, and the coated sand casting process can meet these requirements.

With the advancement of science and technology and the continuous development of casting technology, the coated sand casting process is also constantly innovating and improving. For example, some advanced coated sand casting production lines have realized multiple functions such as data collection, automatic core making, automatic core connection, automatic cleaning, automatic spraying of release agent, rapid mold change and environmental protection dust removal. The application of these advanced technologies has further improved the production efficiency and product quality of the coated sand casting process and reduced production costs and environmental pollution.

6. Summary and Outlook

In summary, the coated sand casting process occupies an important position in modern casting production with its advantages of high precision, high efficiency, good disintegration, strong adaptability and good environmental protection. With the advancement of science and technology and the continuous development of casting technology, the coated sand casting process will be more widely used and developed. In the future, we expect the coated sand casting process to show its unique advantages and value in more fields and make more significant contributions to the development of the metal processing industry.