Tooling Design For Investment Casting(lost wax casting)


When it comes to metal casting and CNC machining, tooling refers to reusable items that are utilised for each job. Wax-injection dies are used as tooling to create wax patterns in investment casting. 

If you know how investment casting works, you already know that the investment casting process relies on these wax patterns. Wax has smooth surfaces, low melting temperatures, and excellent flow properties enabling highly complex investment castings to be made.

Investment casting tooling design

By following strict guidelines based on decades of experience, foundries can recommend design changes to improve product quality and function, as well as to increase production efficiency and decrease manufacturing costs.

Most of the time, the customer is in charge of the casting design. Casting facilities work with customers to optimise designs for manufacturability and to ensure they pass through a rigorous Advanced Planning Quality Process (APQP).

in addition to our own die manufacturing facilities, we also work with over 200 suppliers who also produce high-quality investment casting dies. We produce wax dies with CNC mills, lathes, and electrical discharge machining (EDM) machines. Finally, we finish the tools manually by polishing or filing.

In order to optimise materials, dimensions, and critical surfaces, the foundry works directly with the toolmaker. It is also possible for the tooling to remain at the foundry during production, but in most cases, it belongs to the customer who ordered the casting. The wax injection die is an asset that can easily be transferred between foundries if necessary.

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Investment casting tool materials

Investment casting dies are often made from aluminum, which is used for wax-injection. Aluminium has a number of properties which make it an excellent investment casting material. A major advantage of the material is its thermal properties, which allow heat to dissipate quickly, thus assisting with the reduction of cycle times during wax injection.

Additionally, aluminium is less dense than other alloys, so aluminium dies are lighter and easier to handle. Finally, aluminium is an easily machinable material, so the cost of manufacturing aluminium dies is relatively low. Aluminium stock is not expensive and is easily available.

The wax injection process does not wear out aluminium die cavities since investment wax is non-abrasive. Steel, brass, or anodized aluminium are often used to make moving parts or components that experience friction during moulding.

Cost factors for investment casting tools

In comparison with other casting processes, investment casting tooling can be much less expensive. Depending upon the tool, the cost can range from $2,000 to over $20,000. A further reason for the importance of Design for Manufacturability is that it takes into account cost variables across the entire manufacturing process. In spite of the initial investment, wax injection dies to have a number of advantages:

· Casting complexity affects investment casting tool costs. When parts are overly complex, more moving parts are required within the tool, which makes the process more complicated.

· Size. Tools for larger parts require more material for construction and require more time for machining the mold cavity.

· Some cases may require soluble cores. Despite their benefits in the production of complex inner cavities, soluble cores do require their own tool, resulting in increased tooling costs up front.

With its nonabrasive properties and relatively low melting temperatures, investment tooling can easily handle 250,000 injections. In most cases, wear can be easily repaired without excessive downtime. Die repairs are typically necessary because the excessive flash on wax patterns occurs when moving parts of the tooling engage with one another.

As with any manufacturing process, investment casting involves the design and production of tooling. Investment casting customers can better predict costs and timelines for bringing a new product to market by understanding the production, costs, and variables associated with wax-injection dies.