Investment casting

Investment casting (lost wax casting) includes processes such as wax pressing, wax repairing, tree assembly, slurry dipping, wax melting, casting of molten metal, and post-processing.

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Certifications ISO 9001:2015 | CTQ Inspections | ISO 13485

Lost wax casting involves making a wax pattern of the part to be cast using wax, and then coating the wax pattern with slurry to form a clay mold. After the clay mold dries, it is placed in hot water to melt the internal wax pattern. The clay mold is taken out from the melted wax pattern and fired into a ceramic mold, which is fired once. Generally, a sprue is left when making the clay mold, and then molten metal is poured through the sprue. After cooling, the required part is produced.

Materials used in lost wax casting:

Carbon steel
Alloy steel
Heat-resistant alloy
Stainless steel
Precision alloy
Permanent magnet alloy
Bearing alloy
Copper alloy
Aluminum alloy
Titanium alloy
Ductile iron, etc.

Parts produced by lost wax casting are generally complex in shape. The minimum diameter of castable holes on the castings can reach 0.5mm, and the minimum wall thickness of the castings is 0.3mm. In production, some parts that were originally composed of several components can be combined. By changing the structure of the parts, they can be designed as integral parts and directly produced by investment casting, which saves processing man-hours and metal material consumption, and makes the part structure more reasonable.

The weight of parts made by lost wax casting mostly ranges from a few grams to tens of kilograms (generally no more than 25 kilograms). It is more troublesome to produce overly heavy castings by investment casting.

The lost wax casting process is relatively complex and difficult to control, and the materials used and consumed are also more expensive. Therefore, it is suitable for producing small parts with complex shapes, high precision requirements, or those that are difficult to process by other methods, such as turbine engine blades.

Benefits of Lost Wax Casting Process

Production of Large Components: Capable of manufacturing large parts.
Complex Shape Forming: Enables the creation of intricate geometries.
High-Strength Parts: Results in components with excellent mechanical properties.
High Productivity: Efficient for mass production runs.
Superior Dimensional Accuracy: Lost wax castings typically achieve CT4-6 tolerance levels (sand casting: CT10-13; die casting: CT5-7).
Water Glass & Low-Temperature Process: Supports casting weights from 0.5kg to 100kg using materials such as carbon steel, alloy steel, stainless steel, and wear-resistant alloys.
Excellent Surface Finish: Surface roughness (Ra) ranges from 1.6 to 3.2μm, exceeding standard casting finishes.
Cost & Material Efficiency: Reduces reliance on machining and raw material consumption.
Alloy Versatility: Ideal for complex castings in various alloys, particularly high-temperature alloys. For example:
- Jet engine blades with aerodynamic profiles and cooling channels, which are challenging to machine, can be mass-produced with consistent quality and without stress concentrations from tool marks.

Lost Wax Casting Hardware Processing Technology

Lost wax casting (investment casting) involves making a mold of the part to be cast using wax, then coating the wax mold with slurry to form a clay mold. After the clay mold dries, it is heated to melt the internal wax mold. Once the wax mold has melted, the clay mold is removed and baked to form a ceramic mold. Generally, a gating system is reserved during the production of the clay mold, and then molten metal is poured into the mold. After cooling until the part solidifies, the desired component is produced.