Investment casting process（1）
Investment Casting is an industrial process based on lost wax casting, one of the oldest metal forming technologies. The term "lost wax casting" can also refer to the modern investment casting process.
In the past five thousand years, investment casting has been used in various forms. In its earliest form, beeswax was used to create the desired pattern for the casting process. More advanced waxes, refractory materials, and specialty alloys are now commonly used to make patterns. The value of investment casting lies in its ability to produce parts with high precision, repeatability, versatility and integrity from a variety of metals and high-performance alloys.
Fragile wax mold must withstand the mold manufacturing process needs the power. Most of the wax used in investment casting can be recycled. Lost foam casting is a modern investment casting method.
The name of investment casting comes from the refractory material investment model. Many materials are suitable for investment casting, such as stainless steel alloys, brass, aluminum, carbon steel and glass. The material is poured into the cavity of the refractory, which is exactly the same as the desired part. Due to the hardness of the refractory material used, investment casting can produce products with superior surface quality, which can reduce the need for secondary processing.
At present, water glass and silica sol investment casting is the two main investment casting methods. The main difference between the two is the casting surface roughness and cost. Water glass dewaxing into high-temperature water, ceramic mold made of water glass quartz sand. Dewaxing silica sol into flash, silica sol zircon sand made of ceramic mold. The silica sol method is more expensive than the water glass method, but the surface is better.
The process can be used for a few ounces of small castings and weighing hundreds of pounds of large castings. It may be more expensive than die casting or sand casting, but unit costs have been drastically reduced. Investment casting may produce complex shapes, while other casting methods are difficult or impossible to accomplish. It can also produce products with excellent surface quality and low tolerances with minimal surface preparation or machining.
The casting can be made from the original wax model (direct method) or from a wax replica of an original model (indirect method) that does not need to be made from wax.http://www.pump-casting.com/