Non-Free Cutting Mechanism of Asymmetrical Nanogrooves Under Chip-Removal Interference in Amorphous Nickel Phosphorus

Asymmetrical nanogrooves are commonly employed as blazed gratings for precision measurement, optical communication, and optical sensing applications. Diamond cutting is a promising deterministic processing technology for nanogrooves with a triangular cross-section profile. Non-free cutting of nanogrooves makes it hard to suppress the cutting-caused deformation because of the low stiffness of nanogrooves. Focusing on the influence of non-free cutting on the deformation of asymmetrical nanogrooves, this paper systematically investigates the asymmetrical nanogroove cutting in amorphous nickel phosphorous material through mechanism revelation, simulation analysis, and experimental discussion. The materials removal mechanism by two side edges with different slopes in the non-free cutting is revealed according to the shear interference. According to the relative feed direction between tool and workpiece, two types of feed cases in the asymmetrical nanogrooves, named D1 and D2, respectively, are investigated by comparison in terms of deformation mechanism, nanogrooves topography, and nodal stress of tool edges. The extrusion by tool edges and the squeeze by the chip flow mainly influence the deformation of nanogrooves. In the D1 case, the horizontal component of squeeze by the chip flow towards the rear just-fabricated nanogroove, and the severely deformed nanogrooves are stacking together. On the contrary, in the D2 case, the flowing chip squeezes the front uncut materials, relieving the cutting-caused deformation, and asymmetrical nanogrooves have clear V-shaped cross-section profiles. It is proven that the D2 strategy is more suitable for asymmetrical nanogroove machining. The work in this paper will contribute to further understanding of non-free cutting and the processing technology of asymmetrical nanogrooves.