Application of wax in investment casting

In the investment mold (precision) casting industry, wax is the most commonly used mold material. In our ancient times called lost wax method casting process, the process does not require much cutting after molding, fine treatment can be used directly.

The process of investment casting is as follows: the melted wax is pressed into a wax mold according to the size and quality required by the design, several layers of refractory materials are applied on its surface, and after the paste is dried and hardened into a shell, the wax mold is melted out using high temperature steam, and finally the melted metal liquid is poured into the shell, and the metal liquid is cooled and solidified in the shell, which becomes a precise and clean casting after decapping and cleaning.

Wax for investment casting requires melting point in the range of 60℃~100℃, good fluidity, softening point not less than 35℃~40℃, shrinkage rate less than 1%, sufficient strength and surface hardness in solid state, convenient recycling, good reusability, harmless and abundant sources, low price, etc.

Lost wax in casting process is suitable for all types of alloy parts casting, with casting size precision, accurate form, low surface roughness, wide range of application, for the use of other casting process complex, inconvenient processing of objects, can also take the method.

The process flow of lost wax casting is as follows: pressing rubber mold – opening rubber mold – injecting wax – trimming wax mold – planting wax tree – filling plaster cylinder – vacuuming plaster – natural solidification of plaster – baking plaster – melting gold, casting – blowing plaster – rinsing, pickling, cleaning – cutting blank.

The heater and thermostat in the wax injection machine can make the wax liquid reach and maintain a certain temperature usually the temperature of the wax in the wax injection machine should be kept between 70~75℃, such temperature can ensure the fluidity of the wax liquid if the temperature is too low, the wax liquid is not easy to fill the wax mold, causing the wax mold to be defective; on the contrary, the temperature of the wax liquid is too high, which will lead to the wax liquid overflowing from the gap of the rubber mold or from the wax injection mouth, which is easy to form a flying edge or burn your fingers.