Turbine Technologies News

Titanium Utilized for New Centrifugal Compressor Design

Turbine Technologies this week completed its first centrifugal compressor assembly machined directly from titanium.

Since its installation in late December, Turbine Technologies five-axis VF-2TR vertical milling center has been in continuous use in the support of engine development and prototype part production. Throughout this period, considerable resources have been devoted to the test, evaluation, and when necessary, the development of specialized software to translate complicated design geometry into machine-readable tool paths.

"We've made a sizeable investment in our ability to produce turbine engine components of any arbitrary shape, " said Mike Kutrieb, VP of Turbine Technologies. "Our machinists have been producing useful parts for some time now with the new mill including machined aluminum centrifugal compressors that exactly match our desired design geometry. While proving the manufacturing process was our principal goal, these compressors were tested in actual engines. Moving from the cast compressor to the machined version resulted in a performance improvement of over 20%. Despite the cast parts being of the highest aerospace quality, the performance gains realized by geometrically perfect [machined] parts are very encouraging. Our next goal was to produce the part from titanium to benefit from the material's light weight and superior mechanical properties."

Titanium, one of the most abundant elements on earth, is extensively used for aerospace applications. Because of its light weight, corrosion resistance, and high tensile strength at extreme temperatures, titanium alloy is particularly well suited for gas turbine engine components. The material has a reputation for being difficult to machine. Cutting tool heat dissipation and material elasticity are two of the biggest problems. Drawing upon over 15 years of Super Alloy fabrication experience, Turbine Technologies staff approached the problem methodically and realized rapid success.

"With a disciplined approach to the problem, our technicians quickly developed a way to manage the material in the small sizes required of our compressors. Within a few short days we had a finished component cut, installed in an engine and running. I believe this ability to 'try something new' in incredibly short order truly sets us apart in light gas turbine development. At this point, we believe our ability to conceive new designs is the only limiting factor in prototype development."

The company continues to evaluate its options with regard to software and development tools. Since proving its ability to manufacture useable compressors, other parts with unique shapes such as inlet ducts and diffusers have been produced.

Mr. Kutrieb concluded, "We continue to evaluate software as we refine our manufacturing processes. These initial results are highly encouraging and we look forward to further performance gains through the ability to realize in hardware the designs we envision on our workstations."