General Overview
Precision casting broadly covers investment casting, ceramic mold casting, gypsum mold casting and other molding processes. Among them, investment casting (commonly known as lost-wax casting) is the most widely adopted process in industrial applications.
Process Principle: Fabricate part patterns (investment/wax patterns) with low-melting-point materials; coat the patterns layer by layer with refractory binder slurry to form a sealed ceramic mold shell; melt and remove the internal patterns via heating, then conduct high-temperature shell sintering; pour molten metal into the mold shell cavity; cool down and break the mold shell to obtain high-precision near-net-shape metal castings.
Core Technical Indicators
- Dimensional Accuracy: CT4～CT7 grade; typical linear tolerance: ±0.1～±0.4mm (subject to casting dimensions)
- Surface Roughness: Ra1.6～12.5μm; up to Ra1.6～3.2μm with superior surface layer processing
- Minimum Castable Wall Thickness: 0.5～1.5mm; single casting weight range: 1g to several hundred kilograms
- Structural Advantage: No mandatory draft angle required, capable of manufacturing complex structures such as intricate inner cavities, curved surfaces, hollow and integrated monolithic components
Advantages
- Ultra-high molding freedom, enabling integrated casting of multiple parts and reducing assembly procedures
- Excellent surface quality with minimal machining allowance, realizing near-net forming
- Compatible with most ferrous metals, non-ferrous metals and special superalloys
- Applicable to small and medium-sized complex precision parts, supporting both mass production and low-volume trial manufacturing
Classification of Mainstream Process Routes
- Silica Sol Process (High-end Route): Features high dimensional accuracy, smooth surface finish and low porosity, serving as the preferred process for aerospace, medical and hydraulic valve components
- Water Glass Process (Economical Route): Low production cost with relatively lower precision, mainly applied to ordinary rough carbon steel castings
- Composite Binder Process: Balances cost and precision, widely used for general hardware parts
Complete Process Flow Chart
Complete Process Flow Chart
