Experimental Investigation on Magnetic-Field-Assisted Ultraprecision Diamond Cutting of Ti–6Al–4V Microgrooves and Microstructures

Abstract Ultraprecision machining of titanium alloy (Ti–6Al–4V) remains challenging due to its low thermal conductivity, pronounced elastic recovery, and tool–workpiece adhesion, all of which degrade surface integrity and accelerate tool wear. This study systematically investigates the effect of a weak magnetic field (~ 0.015 T) on the single-point diamond turning and microgroove machining of Ti–6Al–4V flat surfaces, microgroove arrays, and microstructures. Four machining conditions were designed to decouple the magnetic field effect: no field (nM–nM), field applied only during microgroove cutting (nM–M), field applied only during finish turning (M–nM), and field applied throughout (M–M). Theoretical analyses and experiments have demonstrated that the rotation of the conductive titanium alloy within a magnetic field induces eddy currents, generating Lorentz damping, which suppresses vibrations in Y / Z directions, enhances cutting stability, and improves surface finish. The results showed that magnetic-field assistance significantly reduces both the principal cutting forces and noise levels, and that performance under M–nM conditions surpasses that under nM–M conditions, suggesting that the finish-cutting process exerts a stronger influence on the quality of microgroove machining. Microstructures machined under M–M conditions exhibit exceptional dimensional accuracy and uniformity, with groove depths approaching a nominal value of 4 μm (reaching ~ 3.98 μm under the M–M conditions) and minimal burrs or microcracks forming at boundaries. The findings enhance the understanding of the magnetic field-assisted ultraprecision cutting of titanium alloys, enabling the manufacturing of high-quality micro/nanostructures for applications in aerospace, biomedicine, and optical components.