Optimizing Incidence Angle and Range for Single-Shot Laser Scanning Point Clouds to Model Aerospace Fasteners

Abstract

In high-precision manufacturing environments, optical metrology technologies allow on-line checking and validation, offering live digital representations, with the broader potential to create digital manufacturing twins. An established typical aerospace application involves the alignment of assemblies where components need to be compared against design tolerances at key manufacturing stages. Accurate, precise and reliable measurement tools such as laser trackers are the popular choice for such processes in large-volume manufacturing settings. A critical aerospace challenge follows alignment, drilling and fastening operations enabling surface covers to be attached to underpinning structures, where the smallest manufacturing variations can cause excess drag impacting aerodynamic performance. Determining surface conformance of airstream facing surfaces challenges laser tracker systems which, whilst capable of localised surface scanning, require costly large volume robotics to productively measure large wing surfaces at high levels of local detail. This technology gap creates opportunity for the use of 3D imaging devices such as medium range laser scanners and detection strategies such as automated feature detection from point clouds. In this work, various laser scanner devices were used to detect fasteners of different sizes on a fastener sample plate from a single shot setup. This fastener sample plate is representative of a typical aerospace surface and is comprised of common aerospace materials. Highly precise measurements, in the range of 0.5 mm were achieved, and conclusions were drawn about optimal range and incidence angle for both aerodynamic and interior sides of an aerospace surface.