Precision casting is also called lost wax casting,Precision castingIts products are precise, complex, close to the final shape of the part, and can be used directly without processing or with little processing. Therefore, investment casting is an advanced technology with near net shape.
Ancient China: Prince Wu Ding, Bronze Forbidden, Bronze Lion, etc., are all masterpieces of investment casting. Since investment casting was used in industrial production in the 1940s, it has been developing at a relatively rapid rate for half a century. Especially European and American countries are developing rapidly. Investment casting is used in aviation, weapons, almost all industrial sectors, especially in electronics, petroleum, chemical, energy, transportation, light industry, textile, pharmaceutical, medical equipment, pumps and valves. China has also developed rapidly in recent years.
The development of investment technology enables investment casting to produce not only small castings, but also larger castings. The outline size of the largest investment casting is nearly 2m, while the minimum wall thickness is less than 2mm. At the same time, investment castings are becoming more precise. In addition to linear tolerances, parts can also achieve higher geometric tolerances. The surface roughness of investment castings is getting smaller and smaller, which can reach Ra0.4μm.
Ceramic type precision casting uses ceramic slurry to make castings to produce castings. The ceramic slurry is mixed with ethyl silicate hydrolyzate and fine refractory sand with pure texture and high thermal stability, such as fused quartz, zircon, corundum, etc. In order to make the ceramic slurry gel in a short time, calcium hydroxide or magnesium oxide is often added as a catalyst. Because the composition and appearance of the refractory materials used are similar to those of ceramics, it is called ceramic type. Ceramic mold casting is a new process developed on the basis of ordinary sand casting.Dongguan Precision Casting.
There are two types of ceramic type:
①The ceramic type is made by pouring ceramic slurry. The manufacturing process is to first fix the pattern on the mold plate, coat the sand box, and then pour the adjusted ceramic slurry into the sand box. After the glue is hardened, the mold is removed, and the mold is baked at high temperature.
②Using a bushing, pouring ceramic slurry in the gap between the bushing and the pattern to make a mold. The bushing can be sand type or metal type. Pouring ceramic shells with bushings can save a lot of ceramic slurry, which is more widely used in production. The surface roughness of ceramic castings can reach Ra10～1.25 microns, and the dimensional accuracy can reach grades 3～5, which can achieve the purpose of less cutting and processing. Ceramic mold casting has a short production cycle and high metal utilization. The largest castings can reach more than ten tons, which are mainly used for casting large thick-wall precision castings and casting single small batches of die, forging dies, plastic molds, metal molds, die-casting molds, glass molds and other molds. The service life of ceramic casting molds is comparable to that of molds made by machining methods, and the manufacturing cost is lower than that of molds made by machining methods.