Precision Casting Technology

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Precision Casting Technology
Precision casting is the general term for the process of obtaining castings of precise size. Compared with traditional casting process, precision casting results in more accurate casting size and better surface finish. Its products are sophisticated, complex and close to the final shape of the part. Can be used without processing or processing. It is an advanced technology of near – net forming. It includes investment casting, ceramic casting, metal casting, pressure casting, lost casting.

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What is precision casting?
In the production of precision casting parts is the most commonly used precision investment casting, also known as lost wax casting. Widely used in the production of ferrous and non-ferrous metal castings. The embedding mold is made of paraffin wax and other suitable embedding materials. Repeat the refractory coating and refractory sand process on the investment mold. The shell hardens and dries. The internal melting die is then melted to obtain the cavity. Get the crust baked to get enough strength. Burn off the remaining embedding material and pour the required metal material. Solidification, cooling, peeling, sand clearing. To get a high precision finished product. Perform heat treatment, cold processing and surface treatment according to product requirements.
In addition, precision castings have a lot of freedom in the design of castings and the choice of materials. It allows investment in a variety of steels or alloyed steels. So in the casting market, precision casting is the highest quality casting.

The main process of precision casting
Because precision casting uses expendable models and ceramic casings, it is well suited to complex and detailed part designs. The process creates complex parts that are difficult, if not impossible, to machine, forge or cast. Examples include internal channels and ports in the valve body, curved blades in the impeller, and internal cooling channels in the turbine blades. The key barriers to prototype development and short-term production are the time and cost of injection molding. Each precision casting requires a wax mold, which is injection molded. As design complexity increases, tools often become too expensive and time consuming to make prototyping and small batch production feasible.It includes the following steps: waxing (wax mold) – repair – wax inspection – group tree (wax mold tree) – hulling – dewaxing (steam dewaxing) – baking mold – chemical analysis – casting (pouring molten steel in mold shell) – Vibration hulling – casting and casting rod cutting and pouring – grinding gate – initial inspection (wool inspection) – shot blasting – Machining – polishing – finishing inspection – packaging.

Precision Casting
Investment casting tools
The tool in investment casting is considered to be the wax injection mold used to create the wax mold. Each part starts with a wax mold, and the properties of wax — smooth surface, low melting temperature, and excellent flow characteristics — make highly complex investment castings possible. In terms of how investment casting molds are designed, usually, the customer is the person responsible for the casting design. A good foundry will work with customers to ensure that their designs are optimized for manufacturability and go through the quality process. Foundries can recommend design changes to improve product quality and functionality while improving manufacturing efficiency and reducing costs. Once the design is determined and agreed upon by the customer and supplier, the foundry will work directly with the tool manufacturer to design the tool. Foundries work directly with tool manufacturers to ensure that materials, dimensions, and critical surfaces are optimized.

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What factors affect the cost of investment casting tools?
1.Casting complexity, an overly complex part may require the use of more moving parts in the tool, which increases the time and number of processes required to build it.
2.Size, larger parts means larger tools, which requires more materials to build the tool, and more time to process the mold cavities in the tool
3.In certain cases, a soluble core may be required. While soluble cores are an important asset for producing complex cavities, they require their own tools, which increases upfront tooling costs