Study of laser precision ablating texture patterns on large-scale freeform surface

Texture patterns are fabricated on the surface of freeform parts in order to improve the performance, and to meet special functional requirements. Due to its low processing efficiency and poor processing accuracy and quality, the conventional mechanical processing cannot fully meet the requirements of the texture pattern processing on parts surface. A novel laser cross-scale micro-3D processing technology, named laser ablation by projective galvanometer scanning (LPAGS), which can fabricate texture patterns on freeform surface with high efficiency and precision has been developed in this paper. The new method is based on the combination of multi-axis machine tool and 3D galvanometer scanning laser processing head. An equal arc length projection was adopted to establish reasonable and undistorted processing model on freeform surface. By reasonable division plan, freeform surface was divided into sub-areas, sub-layers and sub-blocks. Patterns on each sub-area were converted into 2D scanning processing path by reverse projection. By systematically studying the effect of the variation of surface curvature on the focused laser spot shape, energy distribution in laser spot, the criterions of surface partition which satisfy the processing dimensional accuracy and quality were given. The experimental results demonstrate the effectiveness of this method in fabricating texture patterns on large-scale freeform surface.