What is the lost wax method?

The lost wax method is a type of lost mold method. The lost mold method is to use refractory molding materials to cover the loseable mold to form an integral mold without mold lines. Such formable materials are all formable materials that are fusible, volatile, or leave only a small amount of ash after burning, so they are easy to clean, such as hard animal fat, beeswax, rosin, plant fibers, etc.

As early as the 1980s, Bana discovered that bronze vessels with corded handles had no traces of mold lines on the handles, and some had obvious traces of thick fibers on the ears. He believed that these lifting beams were molded from ropes, wrapped in refractory materials, and then burned. The molds were burned to ashes, and the ashes were cleaned before being cast into shape.

Extended information

China's lost wax casting technology first appeared in the middle and late Shang Dynasty. During the Spring and Autumn Period and the Warring States Period, people used the lost wax method to cast bronzes. They first used beeswax to make a model of the casting, and then filled the clay core with other refractory materials and laid it out to form an outer mold.

After heating and baking, all the wax mold is melted and lost, turning the entire casting model into an empty shell, and then the molten liquid is poured inside to cast the object. From the Han and Tang dynasties to the Ming and Qing dynasties, the lost wax method was passed down and carried forward by generations of craftsmen, and has endured for a long time.

In the 1940s, most aircraft engine turbine blades were manufactured using precision forging processes and were prone to fracture. An American engineer solved this problem by using the lost wax casting process.

The engineer improved this method and named it investment casting, making it a key technology for producing aircraft engine turbine blades. After the founding of the People's Republic of China, while introducing precision casting turbine blade technology, two academicians, Rong Ke and Shi Changxu, joined forces to use the lost wax method combined with a quartz tube to fill the casting mold. After completing precision casting, they used hydrofluoric acid to The quartz tube was removed by etching, and hollow turbine air-cooled blades were successfully manufactured.