Forming and application of Investment casting
Investment casting is an industrial process based on lost-wax casting, one of the oldest known metal-forming techniques.The term "lost-wax casting" can also refer to modern investment casting processes.
Investment casting has been used in various forms for the last 5,000 years. In its earliest forms, beeswax was used to form patterns necessary for the casting process. Today, more advanced waxes, refractory materials and specialist alloys are typically used for making patterns. Investment casting is valued for its ability to produce components with accuracy, repeatability, versatility and integrity in a variety of metals and high-performance alloys.
The fragile wax patterns must withstand forces encountered during the mold making. Much of the wax used in investment casting can be reclaimed and reused.just remove the water and Miscellaneous,and right now more and more advantange factories have the automatic wax recycle system.
Investment casting derives its name from the pattern being invested (surrounded) with a refractory material. Many materials are suitable for investment casting; examples are stainless steel , brass, aluminium, carbon steel and glass. The material is poured into a cavity in a refractory material that is an exact duplicate of the desired part. Due to the hardness of refractory materials used, investment casting can produce products with exceptional surface qualities, which can reduce the machine processes.
Investment casting have two process , one called Water glass(liquid is water-glass) another called silica sol investment casting ,The main differences are the surface roughness , dimensions accuracy ,cost of casting. Water glass method dewaxes into the high-temperature water, and the ceramic mold is made of water glass quartz sand. Silica sol method dewaxes silica sol zircon sand makes the ceramic mold. Silica sol method costs more but has the better surface than the water glass method and can use more high inject wax machines,so it can be get more thin thickness goods, the min thickness can be 1.5mm.
The process can be used for both small castings of a few ounces and large castings weighing several hundred pounds, si t widely used for industries , cars , and so on.