Differences in wax materials in precision casting

Differences in wax materials in precision casting

With the rapid development of science and technology and industrial production, the application scope of precision casting technology is constantly expanding. It is difficult to synchronize the performance and quantity of wax with the rapidly developing investment casting industry. So, various organic materials, plastics, and inorganic salts were successively adopted. Some are added as fillers to wax, while others directly replace wax to make molds. Therefore, wax molds and wax materials have gradually been replaced by mold materials and investment molds. However, under normal circumstances, people are still accustomed to being called "wax models". Today, precision casting manufacturer Tianyao Metal will talk to you about the differences in wax materials.

Generally speaking, the higher the melting point of the mold material, the higher its thermal stability; On the contrary, the lower the melting point, the lower its thermal stability. So, according to the melting point of the mold material, it can be divided into three categories: high melting point mold material, medium melting point mold material, and low melting point mold material. If considered from the perspective of thermal stability, it can be divided into high-temperature mold materials, medium temperature mold materials, and low-temperature mold materials.

1、 Low temperature mold material. The melting point of low-temperature mold materials is generally lower than 70 ℃, with low strength, poor thermal stability (30 ℃), large shrinkage, and a large variation in the size and shape of the mold with room temperature. The surface roughness is relatively coarse. The mold material composed of 50% paraffin and 50% stearic acid commonly used in China is a typical example of this type of mold material. However, this type of mold material has a simple production process, high mold material recovery rate, reusability, and lower cost. Generally pressed in paste form, manually operated, can be dewaxed with hot water. This type of mold material is generally used together with water glass binder.

2、 Medium temperature mold material. Mainly rosin wax based and filling molds, with a melting point between 70-100 ℃, high strength, good thermal stability (35 ℃), small shrinkage, good dimensional stability, and fine surface roughness and good replication performance when pressed in liquid form. Reusable, complex production process and high cost. It can be dewaxed with water, steam, or microwave. This type of mold material is generally used in conjunction with silica sol binder. Generally, wax injection machines are used for production.

3、 High temperature mold material. Mainly rosin plastic based, plastic based, and salt based molding materials with a melting point greater than 100 ℃. This molding material has high strength, good thermal stability, and small shrinkage, but the production process is complex and cannot be reused. Generally, flash firing method, water or organic solvents are used for removal. High cost. It is obvious that water-soluble molds and 3D printing molds belong to this category of molds. In investment casting technology, the description of high-temperature mold materials is as follows: this type of mold material has a large thermal expansion, and during demolding, the mold shell often cracks due to insufficient strength.

The above is the difference between low-temperature wax, medium temperature wax, and high-temperature wax materials, hoping to be helpful to everyone.

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