what is Lost-wax casting

Lost-wax casting is a method of casting, which is generally used to cast products with complex three-dimensional structures and common molds (mold combination method) that are not competent. This method has been used to cast bronzes in ancient times, and it is called investment casting in modern precision casting.

Lost wax casting first uses a wax material mixed with beeswax, rosin and tallow to carve the product to be cast (wax mold), then pour the mud washed out of clay onto the wax mold, sprinkle quartz sand, crushed plant fibers, sawdust (sawdust slag) )Wait. After drying, pour clay and yellow mud mixed with clarified mud, and then sprinkle sand. After repeatedly forming the shell on the wax mold, the shell is heated on the fire. When heated, the wax melts into a liquid state and escapes from the mold. After that, the mold shell is sintered (it cannot be potterized, so the sintering temperature is generally not more than 800 °C), and then the molten metal liquid is poured into the mold shell for casting. After cooling, the shell is knocked off, and the cast product is exactly the same as the wax shape.

Lost wax method is a precision casting method of bronze and other metal objects, which is still used in modern industry. It is known that the earliest artifacts cast by the dewaxing method in China belonged to the late Spring and Autumn Period, such as the copper ban in the tomb of Chu in Xichuan Temple, Henan Province, and the exquisite craftsmanship indicates that it was not the original production. As for the production of exquisite and exquisite, Chu made the greatest contribution, and the honor plate of Zenghou Yi's tomb is also the most praised. However, the application of the lost wax method is not popular enough, and there are still not many works seen today. This is related to the limited amount of beeswax and the overly complicated production. Perhaps it is also because the effect is amazing, but it is difficult to elicit a general aesthetic pleasure connection.

Generally, sand casting is made of wooden molds or prototypes. The sand molds must be made into two halves and then put together. The molds must be able to be taken out from the half of the sand molds. The dewaxing method does not have to take out the mold, so it can cast products with complex shapes. Modern precision casting uses very fine foundry sand. It also makes wax molds first, then sprays the sand onto the molds, and fires the sand molds at high temperature to make very fine and complex molds. Very precise parts are directly cast, eliminating the need for machining.