Investment Casting Process – What it is and How it Works
Metal casting is started in antiquity. And in modern times, people developed the investment casting process to create complex and precision metal parts. Without the hassle of more traditional casting methods, the investment casting process can produce low-tolerance, high-precision metal parts.
What is investment casting process
There are four main steps in the investment casting processes:
step 1:Wax Pattern creation
The wax patterns are typically injection molded into a metal mold and are formed . Wax patterns will eventually be the final shape of the casting parts. Cores may be used to form any internal shapes on the wax pattern. To form a tree-like assembly, several of wax patterns are attached to a central wax gating system (including sprue, runners, and risers). The gating system forms the channels through which the molten metal will flow to the casting die cavity.
STEP 2: Lost Wax Mold creation
This wax pattern is dipped into a ceramic refractory slurry. The slurry contains extremely fine silica, water, and other binders. The wax pattern will be covered in a thin layer of slurry. To achieve a certain coat thickness (often 5-10mm), This dipping step is done many times. And then the shell is dried. After drying, the part is turned upside down and heated in an oven. the wax on the inside and excess moisture is melted out leaving a hollow ceramic shell.
step 3 Pouring
The investment casting mold is preheated in a furnace to about 1000°C and then the molten metal is poured from a ladle into the gating system of the casting die, filling the mold cavity. Pouring is typically achieved manually under the force of gravity, but additional methods such as vacuum or pressure are sometimes used.