Scanner Gets First Fit, Right Fit for Aircraft Fixtures

May 26, 2011
NVision handheld device collects millions of data points for reverse-engineering parts
The HandHeld laser scanner is attached to a mechanical arm that moves about the object, freeing the user to capture data quickly, and with a high degree of resolution.

NVision’s HandHeld laser scanner is being used by Lockheed Martin engineers at its Missiles and Fire Control business to ensure that aircraft exterior and interior accessories are positioned to fit perfectly the first time. The scanner is a powerful portable device that is capable of capturing 3D geometry. It attaches to a mechanical arm that moves about the object, freeing the user to capture data rapidly and with a high degree of resolution.

NVision Inc. designs high-accuracy non-contact optical measurement systems and services for reverse engineering and inspection. It offers contract scanning services and systems to the aerospace, power generation, and oil/gas industries. Some notable customers include Alstom, Boeing, GE, Lockheed Martin, Lear, NASA, Porsche, Raytheon, Siemens, Toyota, and the U.S. Dept. of Defense.

NVision’s HandHeld scanner has helped Lockheed Martin engineers accurately measure millions of points by simply moving it over an aircraft’s surface, enabling perfect fits on first prototype iterations.

“The Handheld laser scanner is a perfect fit for this application because its ability to move freely around a part makes it possible to reverse engineer virtually any size or shape of part,” according to Steve Kersen, President of NVision. The scanner is attached to a mechanical arm that moves about the object, freeing the user to capture data rapidly, and with a high degree of resolution. An optional tripod provides complete portability in the field. Intuitive software allows full model editing, polygon reduction, and data output to all standard 3D packages.

“An important advantage of laser scanning is that it provides accurate measurements of parts ranging in scale from the entire exterior of a commercial helicopter down to very small components,” said Stephen Rocca, manager of Mechanical Laboratories at Lockheed Martin Missiles and Fire Control in Orlando, Fla. “Getting the fit correct the first time provides significant time and cost savings. Laser scanning also has improved the accuracy of the fluid dynamic models that we use to predict the effect of the accessories on flight performance, providing a safety advantage.”

In building aircraft accessories, it’s critical to determine the exact geometry of the aircraft that normally cannot be obtained from computer aided design (CAD) models because the exact configuration varies from aircraft to aircraft. For example, aircraft interiors are crowded with cables and hydraulic lines that often do not show up, or show up in a different position in the CAD model.

Previously, conventional measuring instruments were used to physically measure the aircraft. For example, technicians would measure the body exterior, rotor, skids, windows and doors of a commercial helicopter.

This process was very tedious because an individual measurement had to be taken for each point. There was never enough time to take enough points to fully define the geometry so technicians frequently had to take a best guess as to the exact surface contours. The result was that the prototype often had to be reworked to get it to fit the exterior. The inherent inaccuracies of manual measurement methods meant that three or four prototype iterations were typically required to obtain a good match to the aircraft.

After NVision demonstrated the ability to obtain high levels of accuracy in laser scanning, Lockheed Martin purchased an NVision Handheld scanner for a production site in Alabama, and later, a second scanner, for its Orlando manufacturing plant.