3DAI Foils Costly Engine Inspection

  • Published
  • By Hayward Burnett
  • Materials and Manufacturing
WRIGHT-PATTERSON AIR FORCE BASE, Ohio) --  Seeking a more expedient approach to engine airfoil inspection, an Integrated Project Team established an alternate methodology expected to cut substantial time (and consequently, cost) over current techniques, which are too slow for full-rate/surge production or efficient maintenance operations. The IPT--which included Air Force Research Laboratory Manufacturing Technology engineers; Army Aviation and Missile Research, Development, and Engineering Center experts; airfoil casting suppliers; sensor suppliers; and three original equipment manufacturers--developed a Three-Dimensional Airfoil Inspection capability in order to demonstrate the type of high-speed data collection and analysis of complex airfoil geometry needed for achieving significant cycle-time savings.

Engines have hundreds of airfoils. Composed of cast alloys and various organic and ceramic matrix composites, each airfoil takes an average of 1 hr to inspect using current, Coordinate Measuring Machine methods. Conversely, the 3DAI system expedites the inspection process by scanning the airfoil and creating an associated point cloud. The point cloud, which is developed from the inspection data, undergoes comparison to the CAD file of the part. Error maps representing the differences between the CAD dimension and the point cloud are then compared and used to identify part locations shown to be outside of tolerance bands. The overall aim of the 3DAI implementation is to accelerate--by means of a 90% reduction in airfoil inspection time--the rate at which weapons systems are fielded. Meeting this goal translates to decreasing the airfoil inspection period from 1 hr per airfoil to <6 min per airfoil. Thus far, the 3DAI system has achieved 2 to 4 min inspection times.

The cost avoidance projected for this reduction amounts to $26 million--a figure encompassing 1,500 afterburning turbine (fighter) engines rated for 29,000 lbs of thrust. Additional advantages afforded by the technology include reduced airflow variation (which could also enable decreases to total cooling flow), increased engine efficiency, lower fuel consumption, and potentially longer component service life due to better control of cooling at critical locations.

The 3DAI system progressed from a conceptual drawing to a working prototype in 17 months (April 2008 to September 2009). Ultimately, this positive outcome supports ManTech's Advanced Manufacturing Propulsion Initiative, which seeks to transform the Air Force propulsion supplier base in order to assure industrial capability and capacity in meeting production demands and to accelerate the transition of advanced technology. Among the 3DAI technology's potential implementation platforms are the T700, F135, and F136 engines.