What is the binder for investment casting?

In precision casting, binder is a vital component of mold sand, which is used to bond sand grains together to form the frame of the mold. For investment casting, the selection and application of binders have an important impact on the quality and performance of castings.

Types of binders:

Casting starch: Casting starch (also known as pregelatinized starch or α starch) is a commonly used binder, which is widely used in the foundry industry for its excellent bonding properties, low cost and environmental protection. Casting starch is made by mixing starch with water and other additives and then heating it to form a slurry with bonding properties, which is used to bond sand grains and enhance the strength of mold sand.

Synthetic resin adhesive: Synthetic resin adhesive is also a commonly used adhesive. It has low surface free energy, easily wets most adherend surfaces, and can be transformed from a liquid state to a solidified material with a certain strength through physical or chemical changes. This adhesive has excellent bonding properties and can improve the nucleation rate and thermal stability of the material.

The role of adhesives:

The main role of adhesives in investment casting is to bond sand particles to form a solid mold frame so that it can withstand the pressure and weight of molten metal during the casting process.

By adjusting the type, amount and mixing ratio of adhesives, the strength, air permeability, fire resistance and other properties of the mold can be controlled to meet the production needs of different castings.

Precautions for use:

When selecting adhesives, factors such as the material, shape, size and casting process of the casting need to be considered to ensure the stability of the mold and the quality of the casting.

When using adhesives, it is necessary to strictly control their dosage and mixing ratio to avoid problems such as excessive or insufficient strength of the mold or loose bonding of sand particles.

At the same time, it is also necessary to pay attention to the storage and preservation of adhesives to avoid problems such as moisture, deterioration or pollution that affect its use effect.

In short, in investment casting, adhesives are an indispensable component, and their selection and application have an important impact on the quality and performance of castings. By reasonably selecting and using adhesives, the stability of the mold and the quality of the casting can be ensured, and the efficiency and benefits of casting production can be improved.