Enhancing machining efficiency and precision: Water-jet guided laser fabrication of diamond micro-milling tool

The diamond micro-milling tool is a crucial component in micro-milling technology, indispensable for the precise machining of miniaturized parts and structures. However, the manufacturing efficiency of diamond micro-milling tools is challenging due to its extreme mechanical property and micro-sized feature. In this study, Water-Jet Guided laser (WJGL) technology was explored to prepare single-crystal diamond micro-milling tool, aiming to achieve industrial-grade processing efficiency. Both energy-related parameters (laser power and scanning speed) and fluid-related parameters (water flow and shield gas) were investigated to identify the optimal conditions for superior machining quality and material removal rate (MRR). Through cutting through experiments, it was observed that medium laser energy density was most effective in enhancing surface morphology, while high energy led to excessive ablation and low energy resulted in insufficient material removal ability. Moreover, water flow and shield gas affected the kinetic energy of water jet, which reacted on the water stability and subsequent machining quality. MRR was measured and calculated via surface grooving experiments, with ablation ability being the dominant factor. The optimal parameter combination was P = 16 W, v = 6 mm/s, water pressure = 300 bar, and gas flow rate = 1.5 NL/min, achieving the surface roughness Sa/Sz = 149.9 nm/1.503 μ m and MRR of 22.976 × 10^-3 mm³/s. A single-crystal diamond micro-milling tool was finally well-prepared within 2 min, with higher machining precision and efficiency compared to conventional methods, highlighting the potential of WJGL for mass production of high-quality diamond micro-milling tools.