Five-Axis Continuous Sweep Scanning for Curvature Variable Surfaces

Curvature variable surfaces have an extensive application in a multitude of products, such as aeroblades. The aeroblade is an essential part of the aviation industry. The rapid inspection of complex aeroblade is crucial to aviation engine production and maintenance. As an emerging inspection technique, five-axis sweep scanning could achieve higher inspection efficiency compared to the traditional point-by-point probing and line scanning inspection. However, for surfaces with significant curvature variation, such as the blade cross section, the existing five-axis sweep scanning methods require the surface to be separated into patches and conduct inspection on each patch. This type of work pattern necessitates a transition move between each patch, which increases the inspection time and decreases the overall inspection efficiency. In this article, a probe-surface force model is proposed to facilitate the selection of stylus orientations, and an iterative algorithm is introduced to determine the optimal stylus orientations. The guiding curve and the probe head trajectory are synchronized using the dual nonuniform rational basis spline (NURBS) method, which settles the path generation failure at the high curvature region. The proposed method can generate a continuous five-axis sweep scanning path for a blade cross section without transition moves, which drastically boosts the inspection efficiency. Blade cross section inspection experiments are conducted using the proposed method, the patch-wise inspection method, and the line scanning inspection method. The experimental results show that the proposed method maintains the same level of inspection accuracy as both the patch-wise method and the line scanning method. Moreover, the proposed method has achieved a reduction in inspection time of 70.71% over the patch-wise method and 84.98% over the line scanning method, thereby validating its effectiveness.