Additive Repair Process Developed for USAF Aircraft Engine Parts

The US Air Force has awarded Optomec a $1.5 million contract to develop a Metal Additive Manufacturing system and process that enables the repair of oversized titanium components used in aircraft engines. 

The initial target, called Integrally Bladed Rotors (IBRs, or ‘blisks’), are complex, single-piece compressor rotors made of light-weight titanium alloy that are routinely worn or damaged in normal use and can cost more than $500,000 each to replace with a newly made part.

The implementation of an Additive Repair process for these parts is projected to result in greater than 80% in cost savings, which could save the Air Force tens of millions of dollars per year in maintenance costs as well shorten the supply chain for these critical components, used on aircraft such as the F22 Raptor and F35 Lightning II. 

The contract deliverables include the commissioning of a large format 5-axis LENS/DED metal printer with a work envelope of 1500 x 1500 x 1000 mm (5 x 5 x 3 ft), capable of handling IBR/Blisks up to 46” in diameter. The system will be equipped with a proprietary gas purification system that maintains an oxygen and moisture free environment (<10ppm), which is necessary to ensure superior metallurgical and mechanical properties when depositing titanium, especially for flight critical componentry. Additionally, the project will investigate the efficacy of various process monitoring techniques that track key variables as a validation and quality assurance measure.

The project will also employ the capabilities above to develop and demonstrate viable repairs for large blisks, including restoration of both representative wear and foreign object damage across critical areas of the individual blades. In a final step, Optomec will repair various sections of a large scale blisk for evaluation in a spin pit test as an initial step on the path to qualification.

Optomec’s Additive Manufacturing (AM) repair processes are currently used in high volume production for other turbine engine parts worldwide, having repaired more than 10 million components over the last 20 years. This project will scale-up Optomec’s solution for use on larger parts, with diameters greater than 1m. In addition, Optomec will integrate its oxygen-free processing solution for titanium alloys–a key capability for defect-free, high-strength titanium processing.

“As OEMs lightweight and simplify their commercial and military aircraft engine designs, the industry is faced with larger, more complex titanium parts to maintain on the MRO side,” said Jamie Hanson, Optomec’s VP of Business Development. “Optomec is best positioned to deliver production solutions to this growing need, based on its proprietary machine, software and process capabilities, combined with its existing position as the market leader delivering machines for production repair of individual turbine blades. There’s no question that this project with the Air Force will benefit the broader aerospace market significantly over the next ten years.”

Optomec’s LENS Metal Additive Manufacturing machines use a process called Directed Energy Deposition (DED) to build 3D metal parts by depositing powdered metal into a precisely controlled pool of melted metal. Fiberoptic lasers supply the thermal power while advanced motion control systems manipulate the deposition system and part to produce the required geometries. 

Optomec leads the DED market with more than 250 machines in use, including approximately 100 industrial printers used for production repair of turbomachinery used in aircraft and energy applications.