The precision investment castings can be traced back to the ancient time when people at that time trying to do some art craft. In history, the process of making the casting is to use the bee wax to form the shape and then cover in clay. What in the usually the melting metal to make things like idols, jewelry and art works. In words, it is a technique that involves metals and molds.
With the progress and improvement of the technique, the precision investment castings can almost satisfy various shapes you want. One of the most famous industries with the precision castings goes to the dentists. The dentists apply the investment castings to utilize the process to create fillings to be used inside the patient’s mouth. Another example for using the castings are like aerospace, transportation, material handling, pump and valve, food processing and complicated art work. Furthermore, it can be used to create medical implements used inside the human body.
So, how exactly this amazing technique works? It can be briefly explained by list of processes. First, you need to produce a mater pattern which comes from wax, clay, steel or wood. Once you have the pattern, you can start to make a mould. The mould comes from the master pattern, which can be made from low-melting-point metal or can be got directly from the master pattern. Next step is to produce the wax patterns, but the material doesn’t really have to be the wax. It can be plastic or frozen mercury. While making the wax pattern, you can either use a repeated way to make it thick enough or filling the entire mould with wax in one time. As long as the wax was cooled down, it’s time to remove the wax patterns from the mould. Then, by repeating the coating, stuccoing and hardening, you can get the ideal thickness of the investment you want.
After the investment is completely dry, you can do the dewax by turning the mould upside-down and autoclave to melt out and vaporize the wax. In this process, the heat controlling is so important that it might lead your investment work to a mess. When the mold is heated to a certain degrees, between 870 to 1095 Celsius, the mold can be sintered eventually. While in this process, you can also preheated the metal to stay liquid in cases of any cracks found in your work piece. Two more steps before you finish the work: pouring out the investment mold by applying positive air pressure, tilt cast or centrifugal cast and then removed the complete work piece from the mold by vibrated, waterjeted or chemically dissolved.
