Principles and Advantages of Precision Investment Casting

Precision investment casting is an ancient casting process, but it is also a casting process that is widely used today. This process is typically used to manufacture parts that are relatively complex in shape and precision, such as in the aviation manufacturing field, precision investment casting is used to manufacture turbine blades, integrally bladed rotors, and intake nozzles.

Principle of Precision Investment Casting

Precision investment casting, also known as lost-wax casting, involves creating an accurate and meltable model using easily meltable materials (such as wax and plastics). Several layers of refractory coating are applied to the model. After drying and hardening, the shell is formed as a whole. The shell is then heated to melt the model, followed by high-temperature baking to form a refractory shell. Liquid metal is poured into the shell, and after cooling, the casting is completed.

The process of precision investment casting: pattern material - wax pattern pressing - pattern assembly - pattern finishing - coating - sprinkling sand - demolding - baking - pouring - cooling - shell removal - cleaning.

Advantages of Precision Investment Casting

Compared to other casting methods, the main advantages of precision investment casting are as follows:

High dimensional accuracy and low surface roughness of castings, capable of casting complex-shaped parts. Generally, the accuracy can reach grades 5~7, and the roughness can reach Ra25~6.3μm.
Precision investment casting can produce thin-walled and very small castings. The minimum wall thickness of investment castings can reach 0.5mm, and the weight can be as small as a few grams.
Precision investment casting can cast finely patterned designs, texts, and castings with fine grooves and curved thin holes.
There is almost no restriction on the external and internal shapes of investment castings. It is possible to manufacture complex-shaped parts that are difficult to produce using sand casting, forging, and machining. Moreover, some assemblies and welded parts can be directly cast into integral parts after slight structural improvements, reducing part weight and lowering production costs.
Some assemblies and welded parts can be directly cast into integral parts after slight structural improvements, reducing part weight and lowering production costs.
There are almost no limitations on the types of casting alloys, commonly used to cast alloy steel parts, carbon steel parts, and heat-resistant alloy castings.
There are no restrictions on the batch size of precision investment casting production. It can range from single pieces to mass production.