Small hole drilling of Ti–6Al–4V using ultrasonic-assisted plasma electric oxidation grinding

Abstract Ti–6Al–4V is considered to be the most important and useful alloy in the aerospace industry and many other fields. The growing demand for high productivity in machining requires a novel technique for drilling this material efficiently. In this article, a novel grinding technique for drilling with a combination of ultrasonic-assisted grinding and plasma electrolytic oxidation is proposed. The technique was hence named ultrasonic-assisted plasma oxidation grinding (UPOG). A thin oxidized layer was formed on the surface of the workpiece in the grinding zone by plasma. This could enable a reduction of the expensive grinding wheel, which could lead to environmental friendly machining. The oxidized layer would be much softer than the original material. To reveal its fundamental performance in the drilling of Ti–6Al–4V, experiments were conducted to investigate the effect of ultrasonic vibration on grinding forces and tool wear in the presence of plasma oxidation. To investigate the material removal process for UPOG, nanoindentation and nanoscratch tests were also conducted with plasma oxidation samples.