EFFECT OF TEXTURED CUTTING INSERTS IN MICRO-TURNING OF TI-6AL-4V ALLOYS

Abstract

There is an increasing demand for higher machining quality and service life of the cutting tools used for the machining of high-strength alloys. Various studies revealed that textured cutting tools could improve the cutting performance by enhancing the tribological characteristics of the cutting regime. Advances in precision machining enabled the creation of micro/nano-textures on tool surfaces with excellent dimensional control. In this work, distinct micro designs, viz. horizontal line, vertical line and cross-hatch, are made, varying the pitch on the rake faces of coated carbide cutting inserts (CCMT060202LF KC5010). An in-house micro-turning machine was utilized to perform all the experiments in dry-cutting conditions. Micro-turning operations were performed using plain and textured inserts and varying the cutting parameters under dry conditions. The effectiveness of micro-scale textures at a contact interface was evaluated based on the cutting forces, tool flank wear and surface roughness. Compared to non-textured inserts, the machining using cross-hatch textured inserts with 100 µm pitch resulted in 50 % lower cutting forces, a 45 % improved surface finish and 37 % reduced tool flank wear. When machining with horizontal-line textured inserts with a 100 µm pitch, cutting forces are reduced by 46 %, the surface finish is enhanced by 34 % and the tool flank wear is lowered by 30 %. Similarly, when machining with vertical-line textured inserts with a 100 µm pitch, cutting forces are minimized by 38 %, the surface finish is improved by 20 % and the tool flank wear is lowered by 26 %. Additionally, a durability test was conducted for the inserts, and the results showed that the cross-hatch textured tool life improved by 80 %, the life of the horizontal-line textured tool increased by 50 % and the life of the vertical-line textured tool increased by 40 % compared to plain inserts. The heat dissipation and tool-chip friction during machining are thus significantly influenced by the texturing, namely by its design, dimensions and orientation.