The line between art and science can be hard to determine — especially with industrial components when lightness or low mass, or material savings, or efficiency for assembly or fabrication are the design objective. In all those ways, investment casting is an artistic genre for industrial product designers whose technical expertise is in finding the line from a CAD program through a prototype and into the core and molding workshops, and finally into the foundry.
While additive manufacturing captures the attention of many designers, the designer with long-range vision for series production is more likely to focus on investment casting. For component size, material selection, and production efficiency, investment casting has the advantage.
Investment casting design is an area of intense interest for aerospace and automotive manufacturers, as well as in architectural hardware, defense, energy, and medical sectors. And fine art castings also earn recognition.
In October the Investment Casting Institute revealed the best designed investment castings of the past year in seven different categories, during the 66th ICI Technical Conference and Exposition in Indianapolis.
Shellcast Inc. won ICI’s Aerospace Award with a coreless design for a high-pressure valve: aircraft control systems have strict size and weight restrictions, and the high-pressure application also is prone to performance failure due to harmonic pulses.
A typical casting design using pre-formed cores was ruled out due to delivery and to high heat-retention within the core bodies. “By using careful, straight-dipping techniques, our process can achieve high reliability and dramatically reduce internal temperatures during solidification. This allows us to achieve tight NDT requirements in much less time,” recalled quality/engineering manager Gregg Nash.
Aristo-Cast Inc. earned ICI’s Automotive Casting Award with its design for a cast-to-size wheel that requires only minimal machining. “Once again, one of our favorite customers came to us with a challenging detail that not only pushed our limits for size, but also took us into a new area in casting …,” explained Aristo-Cast’s Paul Leonard.
“They first came to us with the design that their generative design software came up with, and we had to suggest a few minor changes to create a better investment casting, and with those small tweaks we then designed the gating configuration to be able to feed the part correctly and reduce the amount of machining that would be required to remove this gating,” he concluded.
TPM Inc. designed a 6-in. valve-seat cage that won ICI’s Energy Casting Award. The 30-lb. part for a reciprocating turbine compressor had previously been fabricated as an 11 piece weldment, but assembling each part was very time consuming.
By converting the part to an investment casting, the customer saved approximately 100 hours in fabrication, machining, and finishing time, as each compressor now consists of eight parts, and approximately $5,000 per compressor.
The ICI casting contest was instituted to recognize foundries that manufacture parts and components that illustrate and promote the benefits and flexibility of the investment casting process, or which demonstrate problem-solving techniques for customers.