Offset-tool-servo diamond end flycutting multi-layer hierarchical microstructures

Abstract

Microstructural functional surfaces inspired by nature have been widely applied in the fields of optics, aerospace, electronics and communication. There function not only originates from a single layer of surface microstructures, but also depends largely on the combined effect of hierarchical structures. Hierarchical microstructures are generally overlapped by two or more layers to generate a functional complementary and combined surface. Fast/slow tool servo technology is usually employed to fabricate micro/nanostructures. However, it is challenging to fabricate multi-layer hierarchical microstructures with sharp edges using only a commercial three-axis ultra-precision lathe. In the present study, a novel ultra-precision offset-tool-servo end flycutting (OTSEF) system was developed. Considering the geometry and installation pose of the diamond tool, a tool path based on the OTSEF system was planned, and different hierarchical microstructures could be fabricated using a compensated linear tool trajectory. Furthermore, a mathematical modeling for tool path generation for complex multi-layer hierarchical microstructures, overlapping micro-lens units with secondary pyramid structures, was established. After determining and compensating for the misalignment between the center of the diamond tool and workpiece, hierarchical microstructures with high precision and quality were successfully fabricated. The theoretical and experimental results demonstrate that the OTSEF system has unique advantages in the fabrication of multi-layer hierarchical microstructures. The present research not only provides a deep insight into tool path modeling but also a machining method for multi-layer hierarchical microstructures.