Several process features of investment casting

[China Aluminum] In considering the following three issues, the main basis is still the basic principles of the general casting process, especially in the determination of process plans, process parameters (such as casting fillet, mold draft, machining allowance , process ribs, etc.) In addition to the specific data due to the slightly different process characteristics of investment casting, the design principles are exactly the same as for sand casting.

We are specializing in:

1. Sand casting (Grey iron, ductile iron, aluminum,etc.)

2. Investment casting (carbon steel, stainless steel, alloy steel,etc.)

3 . Die casting(aluminum, zinc, etc.)

3. CNC Machining(CNC Center, CNC lathe, lathe, drilling machine, milling machine, pressing machine, etc.)

Certificate: ISO9001:2015, TS16949

As with the general casting process design, the investment casting process design task is:

(1) Design the rigging system and determine the module structure.

(2) Analyze the processability of the casting structure;

(3) Select a reasonable process plan, determine the relevant casting process parameters, and draw a casting diagram on the basis of the above.

Investment Casting Features:

Another advantage of the investment casting method is that it can cast complex alloys of various alloys, and in particular can cast high-temperature alloy castings. For example, the blade of a jet engine, its streamlined profile and cooling cavity, can hardly be formed by a machining process. The investment casting process can not only achieve mass production, ensure the consistency of the castings, but also avoid the stress concentration of residual knife marks after machining.

Investment castings have high dimensional accuracy, generally up to CT4-6 (sand casting is CT10~13, die casting is CT5~7). Of course, due to the complicated process of investment casting, there are many factors that affect the dimensional accuracy of castings, such as molds. The shrinkage of the material, the deformation of the investment mold, the change in the amount of wire in the heating and cooling process of the mold shell, the shrinkage rate of the alloy, and the deformation of the casting in the solidification process, etc., so the dimensional accuracy of the common investment casting is high, but its Consistency still needs to be improved (the consistency of castings with medium- and high-temperature waxes is much higher).

When the investment mold is pressed, a molding with a high surface finish of the cavity is used. Therefore, the surface finish of the investment mold is also relatively high. In addition, the shell is made of a high-temperature resistant special binder and a refractory material made of a refractory material and is coated on the investment mold. The inner surface of the cavity directly in contact with the molten metal has a high degree of finish. Therefore, the surface finish of investment castings is higher than that of ordinary castings, generally up to Ra.1.6~3.2μm.

The greater advantage of investment casting is that due to the high dimensional accuracy and surface finish of investment castings, machining operations can be reduced. Only a small amount of machining allowance can be left on the parts requiring higher parts, and even some castings. Only grinding and polishing allowances can be used without machining. It can be seen that the use of investment casting methods can save a lot of machine tool equipment and processing man-hours, significantly saving metal raw materials.