How to choose casting methods for different castings

author: YITECH

2025-03-18

Innovation in manufacturing takes a leap forward with advanced metal casting services, offering precision, durability, and versatility to meet the evolving needs of industries worldwide.

Sand casting is the most commonly used casting method, followed by special casting. The principles of casting methods are as follows:

1. Sand casting is preferred.

Compared with other casting methods, sand casting has the advantages of low cost, simple production process and short production cycle. Therefore, about 60% to 70% of the total output of castings is produced by sand casting. About 70% of sand casting is produced by clay sand mold. In clay sand mold, clay wet mold process should be used first (casting weight can range from a few kilograms to tens of kilograms). When the wet mold cannot meet the requirements, consider using clay sand surface dry sand mold, dry sand mold (casting weight can reach tens of tons) or other sand molds.

Usually, for large and medium-sized castings, cast iron can use resin self-hardening sand mold; steel castings can use water glass sand mold or resin self-hardening sand mold.

When certain performance requirements such as casting accuracy, surface quality, material density, metallographic structure, mechanical properties, etc. are higher, special organizational methods should be used, such as investment casting, pressure casting, low-pressure casting, solid casting, etc.

2. The casting method should be adapted to the production batch.

2.1. The following aspects should be considered for sand casting.

2.1.1. For factories with large-scale production, advanced molding and core making methods should be used.

For small castings, horizontal or vertical parting boxless high-pressure molding lines are used, which have high productivity and small footprint. For medium-sized castings, various box-type high-pressure molding lines and air-blast molding lines are used to meet the requirements of fast and high-precision molding production lines. The core making methods can be selected: cold core box, hot core box, shell core and other efficient core making methods. However, the old-fashioned vibration molding machine production line has low productivity, high labor intensity and high noise, which is not suitable for mass production requirements and should be gradually transformed.

2.1.2. For medium-sized batches of large castings, resin self-hardening sand molding and core making can be selected.

2.1.3. For single-piece small-batch production of heavy castings, manual molding is still an important method.

Manual molding can adapt to various complex requirements and does not require a lot of process equipment. Water glass sand mold, VRH water glass sand mold, organic ester water glass self-hardening sand mold, clay dry mold, resin self-hardening sand mold, cement sand mold, etc. can be selected. For important castings produced in single pieces, pit molding is low in cost and quick to put into production. For batch production or long-term production of stereotyped products, sand box molding and split box molding are more suitable. Although the initial investment in molds and sand boxes is high, it can be compensated by saving molding hours and improving product quality.

2.2. Special casting includes casting methods such as low-pressure casting, pressure casting, and centrifugal casting. Due to the high price of equipment and molds, it is only suitable for batch production.

3. The casting method should be suitable for factory conditions.

Different enterprises have different production conditions (equipment, site, employee quality, etc.), production habits, and production experience. According to these conditions, we should consider choosing a molding method suitable for factory conditions. For example, when producing large machine tool bed castings, pit core molding is generally used without making sand boxes and patterns, while some factories use pattern sand box molding.

4. Consider both the precision and cost of castings.

The casting precision obtained by various casting methods is different, the initial investment and productivity are also different, and the final economic benefits are also different. Therefore, to achieve "good, economical, more, and faster", all aspects should be taken into consideration. A preliminary cost estimate should be made for the selected casting method to determine the casting method with high economic benefits and guaranteed casting quality.

Whether you're an individual or a business, if you want to learn more or you are looking for casting service, please do not hesitate to contact us.

DongGuan YiTai Electronic Technologies Co.,Ltd

DongGuan YiTai Electronic Technologies Co.,Ltd is a manufacturing service provider located in Dongguan, China.

YiTai specialized in CNC turning machining and sheet metal fabrication mainly. As a member of Hung Mou Group, we focus on the overseas marketing development. And based on our parent company’s manufacturing capability and resources, YiTai also expended machining services such as die casting, injection molding, aluminum profile extrusion, 3D printing, which are committed to providing customers with one-stop purchasing services and experience.

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