Top Investment Castings of 2024

The Investment Casting Institute recently completed its 71st Annual Technical Conference and Exposition in Milwaukee – the highlight of which may well have been the results of its 23rd Investment Casting Design Contest. Investment castings is a high-precision process that demands skill and precision from the operators, and frequently reveals those capabilities in the way they duplicate the fine details and extensive geometric variety in a single form.

The annual contest presents awards to the best examples of product design, development, and execution using investment casting in six product areas – automotive, aerospace, defense, oil and gas, power generation, and fine art casting.

Aristo-Cast Inc enhances product quality, cuts buyers’ cost

This mesh trimmed bracket produced by Aristo-Cast, Almont, MI, is a critical element in a chassis node used to support a plastic automotive chassis column. Cast in 17-4 PH stainless steel, the 3.247 x 2.236 x 2.134-in. part replaces a 3D metal printed component.

This investment casting must withstand the rigors of impact crash testing, while staying rigid inside the plastic column without cracking near the node – and it must be lightweight. These requirements were achieved by adopting the investment cast thin-walled mesh structure.

Aristo-Cast used printed investment casting shells (PICS) in the production of this mesh bracket, which provides improved material integrity and can withstand more impact force and has improved dimensional stability when compared with its 3D-printed metal predecessor. Taking this approach, the customer realized a 35% pricing reduction.

It was Aristo-Cast’s first application where the metal part was designed to be over-molded into a plastic chassis column to form the column’s node.

Turbo Cast (India) Pvt. Ltd. promotes new product design

Turbo Cast’s customer developed a new product, the E-Fan, to be used as a cooling solution for Urban Air Mobility. The customer used 3D-printed metal components to validate the concept, after which they turned to Turbo Cast for a production solution.

Turbo Cast was contacted to evaluate the feasibility of part development. Using the investment casting process, they produced the E-Fan’s Housing, successfully reducing manufacturing cost. This component is characterized by an intricate geometry, tight dimensional tolerances and 0.8mm wall thickness.

In consideration of this challenge, investment casting proved to be the only option to make this part. Turbo Cast worked closely with the customer’s design team to understand the application and part requirements. After more than one year of concurrent engineering, the design was finalized, and Turbo Cast successfully developed a robust investment casting process.

Virginia Tech student’s casting impresses

A Virginia Tech professor presented a challenge to students – and student Lillian Coussens found that making the dragon was an exciting opportunity to synthesize everything that she had learned about investment casting.

Coussens’ art piece was modeled from an existing figure, having an intricate shape with both thick (>25 mm) and thin (<1.7 mm) section sizes. Many metalcasting principles were demonstrated by the casting, including creating multiple silicone rubber molds from the original; creating multiple wax patterns; assembling the wax patterns into a complete dragon; creating an investment shell mold on the wax pattern assembly, melting out the expendable wax pattern; and then melting and pouring silicon bronze (Everdur, UNS C87300).

The complex shape of the dragon posed many design challenges; the silicone rubber mold must allow the fragile wax patterns to be removed without breaking and the final investment shell mold must allow the flow of metal into challenging areas, such as the thin, high surface area wings. Problem-solving was required to repair any broken expendable pattern pieces, and to develop strategies to fill thin areas of the silicone rubber mold with wax.

Atlantic Casting & Engineering reduces assembly cost

This housing, formerly made from a three-piece sand-cast assembly, is a critical component for the Abrams Tank turbine engine lubrication pump. Atlantic C&E’s large, single-piece A356 investment casting is a complicated, cored component that is credited with a significant cost saving to the customer by reducing machining and assembly requirements. This component has also demonstrated improved reliability and performance.

By switching from sand casting to the investment casting process the customer was able to obtain components with a superior surface finish, which is particularly advantageous in the winding interior passages, providing a more efficient part at a lower price.

Atlantic C&E was also able to hold tighter overall tolerances when compared to sand castings, giving the customer a vastly superior product. Current production runs at over 95% yield for an uninterrupted supply of castings to the customer.

The casting has 26 intricate cores throughout the part, ranging in diameter from 0.25 to 2.5 in., with a dimensional tolerance of ±0.010 in. To lighten the amount of investment material in and around the part, Styrofoam is placed in the flask prior to investment, which allows the material to form around it. This uses less investment material in the mold, which reduces cost.

The part has both thick and thin areas ranging from 0.160 to 1.06 in. thick.

To produce reliable molds the part is invested under vacuum, which helps to create sound investment in the tight, winding cores that must be free of defects and held to tight tolerances.

This casting is poured under vacuum with 100% ingot to avoid defects. As a result, the optional Hot Isostatic Pressing (HIP) and Impregnation formerly used are not needed.

TPM reduces customer costs by 42%

A stabbing guide is used in oil rig operations: It clamps around drill pipe to provide personnel with a secure way to hold pipe while being moved by an overhead crane. The traditional manufacturing method involved the customer procuring raw castings that demanded subsequent machining and welding.

Upon receiving the initial RFQ and accompanying photos of the finished product, TPM identified several opportunities for enhancement through investment casting, allowing the company to optimize its design and manufacturing process. These enhancements afforded the customer multiple advantages over their original approach.

The original assembly was comprised of a single part, used in pairs to make up both sides of the stabbing guide. This approach resulted in large blocks at each end that required extensive machining to fit the latch and hinge assemblies. With the recommended modifications, the component now includes near-net-shape features that necessitate only minimal machining.

Additionally, the handle, which was formerly attached by welding, required the customer to purchase steel rods and perform shaping and welding of the handle to the assembly. The new approach integrally casts the handle directly onto the component. TPM was able to accomplish these design changes with tooling modifications that use interchangeable inserts to make left and right-side parts, as well as adding the handle section. This change not only enhances the handle’s strength but also provides a more professional finish.

As a result, the customer achieved approximately 42% cost savings by reducing machining and eliminating welding operations while also offering a much more aesthetically pleasing part.

Turbo Cast (India) Pvt. Ltd. reduces manufacturing cost and lead time

This diffuser casting used in nuclear power generation was originally fabricated by welding outsourced plates of 6061 T6 material, which required machining. The resulting product was expensive, with poor aesthetics and excess production lead time.

Due to the excessive lead time and manufacturing cost, the customer tried producing this component by sand casting in LM 25 material. This approach resulted in poor radiographic quality. After multiple failures, the customer turned to Turbo Cast.

Turbo Cast produced this component as a single-piece investment casting, improving dimensional conformity and aesthetic quality while reducing manufacturing cost and lead time.

By converting this part from a sand casting to an investment casting, Turbo Cast successfully met the customers cost and lead time requirements while providing an aesthetically pleasing component.