Last week, a friend asked what is the difference between low-temperature wax and Chinese wax? Please forgive me because I have something to do with my family.
In fact, medium temperature wax and low temperature wax are the names of early mold materials. Although many people still use this title, strictly speaking, it should be called medium temperature mold material and low temperature mold material.
With the rapid development of science and technology and industrial production, the application scope of investment casting technology is expanding. Compared with the rapid development of investment casting industry, the performance and quantity of wax materials are difficult to synchronize. Therefore, various organic materials, plastics, inorganic salts and other materials have been used one after another. Some are added to the wax as filler, and some are directly formed instead of wax. Therefore, wax mold and wax are gradually replaced by mold and investment mold. However, under normal circumstances, people are still used to calling it investment mold. "Wax model". But this "wax model" is no longer that "wax model".
Due to the different types and compositions of die materials, the classification is also more complex. There are two recognized classification methods:
The classification methods are based on the thermal stability of die materials. Thermal stability is an important property of die materials, which is closely related to the melting point of die materials. Generally speaking, the higher the melting point of the die material, the higher the thermal stability; On the contrary, the lower the melting point, the lower the thermal stability. Therefore, according to the melting point of mold materials, it can be divided into: high melting point mold materials, medium melting point molds and low melting point molds. From the perspective of thermal stability, it can be divided into high temperature mold materials, medium temperature mold materials and low temperature mold materials.
Therefore, what we usually call low-temperature wax and high-temperature wax is obviously distinguished by the thermal stability of mold materials or wax materials. This is dot.
The second classification method is determined according to the composition of mold materials. According to the development of modern mold materials, it can be divided into wax based mold materials, rosin based mold materials, plastic mold materials, water-soluble mold materials and filling mold materials.
The above classification method is based on Wang Leyi's classification method investment casting process. The data introduction of these classification methods seems to be basically the same. However, the latter classification method is different: some network data are divided into four categories: wax based mold materials, resin based mold materials, filler mold materials, water-soluble mold materials; Jiang Buju's Practical Investment Casting Technology is divided into unfilled mold materials (wax based mold materials), resin based materials, filler mold materials and water-soluble mold materials, which are basically consistent with the above classification; The following classification method comes from the practical technology of precision casting of Yangshu Mountain.
Table 1 Classification Method of Mold Materials
In fact, no matter how the mold material is divided, all changes are inseparable from its origin. They are basically the same. However, in modern times, a rapid prototyping mold material is a new mold material.
Next, we will further elaborate on the centralized die materials for each classification method.
1. Low temperature mold. The melting point of low temperature die materials is generally lower than 70 ℃, with low strength, poor thermal stability (30 ℃), and large shrinkage. The size and shape of the melting die vary greatly with room temperature, and the surface roughness is large. The mold materials of 50% paraffin and 50% stearic acid in China are typical mold materials. However, the production process of the die material is simple, the recovery rate of the die material is high, the die material can be reused, and the cost is low. General paste pressing, manual operation, hot water dewaxing can be used. This mold material is usually used with water glass adhesive.
2. Medium temperature mold material. It is mainly rosin wax based mold materials and filling mold materials, with a melting point of 70-100 ℃, high strength, good thermal stability (35) ℃), small shrinkage, good dimensional stability, fine surface roughness and good replication performance. It can be reused, the preparation process is complex and the cost is high Steam or microwave dewaxing. The mold is generally used with silica sol adhesive. Generally, it is produced by waxing machine.
3. High temperature mold. Mainly rosin plastic base The melting point of plastics and base mold materials is higher than 100 ℃. The mold has high strength, good thermal stability and shrinkage, but the production process is complex and cannot be reused. Flash firing method is generally adopted Remove water or organic solvents. The cost is high. It is clear that the water-soluble die is water-soluble The 3D printing mold material belongs to this mold material. The description of high temperature mold material is that the mold material has large thermal expansion, and the shell is often cracked due to insufficient strength during demoulding.
Qingdao Xinnuoke Holdings Group limited company.