Tool texturing for micro-turning applications - an approach using mechanical micro indentation

Cutting tool texturing is considered beneficial during the machining process because it could act as lubricant reservoirs to supply extra lubricant and help to entrap the wear debris, which results in the reduction of friction and tool wear. However, due to the exorbitant cost associated with laser-based tool texturing and difficulty in generating precise texture geometry in micro-inserts using alternate methods, the application of tool texturing in micromachining has not gained much popularity. This paper proposes a methodology utilizing mechanical micro indentations for generating microtextures on the flank face of the micro-turning inserts. Square pyramid-shaped micro indentations are made on the flank face of coated tungsten carbide inserts using Vickers microhardness tester. The proposed method eliminates the issue of coating delamination observed in other tool texturing approaches. Micro-turning experiments under Minimum Quantity Lubrication (MQL) conditions are performed on Ti-6Al-4V alloy, and the machining performances are analyzed to evaluate the effectiveness of the proposed methodology. Mechanical micro indentation textured inserts showed a reduction of 21% in cutting forces, 6% in surface roughness, 7% in cutting temperature and 19% in tool flank wear compared to non-textured inserts. The proposed method is observed to be promising, and the process improvement is found to be comparable with alternate approaches of tool texturing reported in the literature.