Understanding the Machining Process of Hierarchical Micro/Nanograting Structures Used for Optical Variable Device

• A novel machining strategy for hierarchical micro/nanograting structures is developed via tool trajectory control, enabling fabrication of optical variable devices (OVDs). • A coupled Euler-Lagrange finite element model accurately simulates the machining process, revealing that increasing tool edge radius reduces nanograting height. • Array overlap machining with optimized coding schemes achieves high-quality OVDs, successfully coloring metal surfaces (e.g., aluminum alloys) with intricate logos. • The proposed method offers a practical, scalable approach for producing structural colors and anti-counterfeiting features, advancing precision manufacturing.