Views:1 Author:Site Editor Publish Time: 2020-12-01 Origin:Site
Investment casting is an industrial process based on lost wax casting, which is one of the oldest known metal forming techniques. The term "lost wax casting" can also refer to modern investment casting processes.
The following knowledge points are listed below:
What is investment casting?
Advantages of investment casting parts
How is lost wax casting done?
The product made by investment casting process is called investment casting part.
Over the past 5,000 years, investment casting has been used in various forms. In its earliest form, beeswax was used to form the patterns required by the casting process. Nowadays, more advanced waxes, refractory materials and special alloys are usually used to make patterns. Precision casting is valued for its ability to produce components with accuracy, repeatability, versatility and integrity in various metals and high-performance alloys.
The name of the precision casting is derived from the pattern of using refractory materials for investment (surrounding). Many materials are suitable for precision casting. Such as alloys, brass, aluminum, carbon steel and glass. Pour this material into a cavity of refractory material, which is an exact replica of the desired part. Due to the hardness of the refractory materials used, investment casting can produce products with excellent surface quality, thereby reducing the need for secondary processing.
Water glass and silica sol investment casting are the two main investment casting methods today. The main difference is the surface roughness and casting cost. The water glass method is dewaxed in high temperature water, and the ceramic mold is made of water glass quartz sand. The silica sol method is dewaxed into fire, and the silica sol zircon sand is made into a ceramic mold. The silica sol method is more costly than the water glass method, but has a better surface.
This method can be used for small castings of several ounces and large castings weighing hundreds of pounds. It may be more expensive than die casting or sand casting, but with mass production, the unit cost will decrease. Investment casting can produce complex shapes, while other casting methods are difficult or impossible. It can also produce products with excellent surface quality and low tolerances, while requiring minimal surface finish or machining.
It has smooth surface and high dimensional accuracy. Investment casting can cast extremely complex parts. Almost any metal can be cast and there will be no burrs or parting lines.
The lost wax casting method, also known as the cire-perdue process, is a metal casting method in which molten metal is poured into a mold made from a wax mold. Once the mold is made, the wax will melt and drain.
In order to cast the clay model into bronze, it is necessary to use the model to make a mold, and then use molten wax to brush the inside of the bottom mold to the desired final bronze thickness. After removing the mold, the obtained wax shell is filled with a heat-resistant mixture. The wax tube is installed on the outside of the wax shell. The wax tube provides a channel for the copper during the casting process and provides ventilation holes for the toxic gas generated in the process. The wax tube can be modeled or adjusted by the artist. Hammer the metal pin through the housing into the core to secure it. Next, completely cover the prepared wax shell in the heat-resistant plaster layer, then turn it upside down and put it in the oven. During the heating process, the plaster dries, and the wax flows out through the duct formed by the wax tube. Then the mortar mold is filled in sand, and the molten bronze is poured into the pipe to fill the space left by the wax. After cooling, remove the outer plaster and inner core, the bronze may be finished.
Precision casting is used in aerospace and power generation industries to produce turbine blades with complex shapes or cooling systems.
Investment casting is also widely used by gun manufacturers to make gun receivers, triggers, hammers and other precision parts at low cost.
Golf club head is also the field of investment casting.