Challenge
The next generation of jet engines must run hotter in order to provide improved performance, including improved efficiency and reduced emissions. To meet those goals, new turbine blade designs are needed that have complex, internal cooling passages that allow the blades to withstand the higher operating temperatures required for improved performance. Ceramic cores are used during the investment casting process to produce those internal passages. Developing new, advanced ceramic cores is a time consuming and expensive process, making product improvements a significant challenge and is limiting design innovation.
Using TOMO, Mikro has developed a breakthrough, fast, lower-cost development process for cores with advanced cooling features and has demonstrated the effectiveness of the process in a program for the US Air Force.
TOMO Application
The goals of the program were to show that TOMO could produce cores with advanced engineering performance compared to conventional processes and at the same time reduce tooling costs and lead times.
The application of TOMO to ceramic cores took place over a number of phases:
- Development of a new, high-strength ceramic binder system.
- Development of a high-temperature sintering process, including binder removal (for fused silica and alumina ceramics)
- TOMO tool fabrication (see TOMO Technology).
- Production of prototype ceramic cores
- Directionally solidified (DS) and single crystal (SX) casting trials
- Analysis of test results
- Analysis of tooling lead times and costs
Fast Development Process for Advanced Ceramic Cores
When compared to conventional manufacturing processes for investment casting cores, it was proven that using TOMO can reduce production lead time from a baseline of 30 weeks to as little as 8-12 weeks – an improvement of 70%.
TOMO’s cost advantage was also demonstrated with tooling costs amounting to $50K-$100K, compared to conventional tooling, which averages $250K-$300K. Using TOMO, total production and development costs can be reduced by as much as 50%.
Additionally, the green-state cores made using TOMO were stronger than conventional cores, and process yields improved from the standard 50% to 85%.
Further Application
Mikro has demonstrated that using the TOMO process can significantly improve the product development process for advanced ceramic casting cores. Based on this success, Mikro is now working with a major manufacturer of industrial gas turbines to produce prototypes of breakthrough turbine blade designs.
