Investment casting, also known as lost wax casting, was created 5,000 years ago. This casting method provides precise, repeatable and versatile parts with different metals and high performance alloys. This casting method is suitable for casting smell and precision parts and is more expensive than other casting methods. With mass production, the unit cost will drop.
Investment casting process:
Wax Pattern Making: Investment casting manufacturers should make wax patterns for their wax castings. Most investment casting processes require advanced casting waxes to complete this step.
Wax tree assembly: The cost of producing a single investment casting product is high, and with wax tree assembly, investment casting manufacturers can create more yields.
Shell making: Make shell bags on wax trees, solidify them and use them in the next casting process.
Wax removal: Removing the wax inside will provide a cavity where you can pour molten metal into the finished casing.
Shell knock off: After the molten metal solidifies, knock off the shell to get the metal casting product tree. Cut them from the tree and you will have the final investment cast product.
Technical features:
1. High dimensional accuracy and geometric accuracy;
2. High surface roughness;
3. It can cast castings with complex shapes, and the alloys to be cast are not limited.
Disadvantages: complicated process and high cost
Application: suitable for the production of small parts with complex shapes, high precision requirements, or difficult to perform other processing, such as turbine engine blades, etc.
1. It can cast complex castings of various alloys, especially superalloy castings. For example, the streamlined outer profile and cooling inner cavity of the blade of the jet engine can hardly be formed by the machining process. The production of investment casting I technology can not only achieve mass production, ensure the consistency of the casting, but also avoid the stress concentration of the residual blade lines after machining
2. The dimensional accuracy of investment castings is relatively high, generally up to CT4-6 (CT10~13 for sand casting and CT5~7 for die casting). Of course, due to the complexity of the investment casting process, there are many factors that affect the dimensional accuracy of castings, such as the shrinkage of the mold material, the deformation of the investment mold, the linear change of the mold shell during the heating and cooling process, the shrinkage of gold and the deformation of the casting during the solidification process, the dimensional accuracy of ordinary investment castings is relatively high, However, its consistency still needs to be improved (the dimensional consistency of castings with medium and high temperature wax should be improved a lot)
3. When pressing the investment mold, the mold with high surface finish of the mold cavity is used. Therefore, the surface finish of the investment mold is also relatively high. In addition, the mold shell is made of fire-resistant coating made of special high-temperature resistant adhesive and refractory materials, which is coated on the investment mold. The surface finish of the mold cavity directly in contact with the molten metal is high. Therefore, the surface finish of the investment casting is higher than that of ordinary castings, generally up to Ra.1.3.2 μ m.
4. The biggest advantage of investment casting is that because investment casting has high dimensional accuracy and surface finish, it can reduce the machining work. Only a small amount of machining allowance can be left for the parts with high requirements, and even some castings can be used without mechanical processing. It can be seen that the investment casting method can save a lot of machine tools and processing time, and greatly save metal raw materials
Post time: Nov-02-2022