Investment casting is a precision casting process that creates complex metal parts using fusible patterns.
The process includes: forming the die → pressing the wax pattern → assembling the die → applying paint → sanding → hardening → dewaxing → firing → pouring → cleaning. Details are as follows:
Mold Making
The mold is refined through various processes, typically made of aluminum alloy, and its shape must match the product half. The mold typically features an upper and lower cavity design, refined through various processes such as turning, planing, milling, etching, and electrical discharge machining. The shape and size of the cavity must match the product half. Since industrial wax is commonly used for die casting, aluminum alloy is selected for mold making due to its low melting point, moderate hardness, affordability, and lightweight.
Wax Pattern Production and Processing
Industrial wax solid core patterns are produced using aluminum alloy molds and bonded to the die head. Normally, each pattern corresponds to only one blank product. After finely trimming the wax pattern’s peripheral margins and removing burrs, multiple individual wax patterns are bonded to a pre-prepared die head. This die head is also manufactured from a solid core pattern of industrial wax.
Sandblasting and Air-Drying Process
Glue is applied and sprayed with high-temperature resistant sand of varying particle sizes, allowing the pattern to air-dry naturally at a constant temperature to achieve a smooth surface. Industrial glue is applied to the wax pattern fixed to the die head, and a first layer of fine sand is evenly sprayed. This sand is refractory and heat-resistant, typically silica sand, with very small and fine particles, ensuring a smooth surface finish. The sandblasted wax pattern is then air-dried at a set room temperature or constant temperature, ensuring that the internal shape of the wax pattern is not affected.
Baking and Dewaxing
Heating dewaxes the wax pattern, creating a sand shell for precision casting and enhancing its adhesion and brittleness. Before baking, a layer of white industrial latex (silica slurry) is evenly applied to the sandblasted wax pattern to enhance adhesion and curing, as well as to seal the wax pattern. The wax pattern, secured to the die head and sandblasted and air-dried, is placed in a sealed, dedicated oven for heating.
Liquid stainless steel water is poured into the sand shell, where it cools and solidifies to form a stainless steel blank. Before adding the stainless steel water, the sand shell is further baked to enhance its strength and stability. This step is usually performed in a high-temperature furnace. The liquid stainless steel water will fill the spaces previously formed in the wax pattern and completely fill the mold.
Finishing and Inspection
The blank is cleaned and reprocessed to remove defects and ensure product quality. After passing inspection, the blank is cleaned to remove surface impurities and defects such as pinholes and pores. Finally, other necessary processing steps are performed until the final product is complete.
The above is the complete investment casting process, intended to provide a comprehensive reference. Of course, if you have large-scale investment casting needs, you can partner with Mulan Metal. Mulan Metal has 12 years of investment casting experience and has successfully completed investment casting operations for clients in over 30 countries, earning unanimous praise. We look forward to your consultation and cooperation.
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