Tool wear in disk milling grooving of titanium alloy

The work efficiency of grooving machining can be improved by the approach of disk milling. However, the problem of tool wear was serious because of big milling force and high milling temperature in manufacture process, by which the tool life and the machined surface quality were influenced. In this study, disk-milling grooving experiments of titanium alloy were designed and conducted. First, milling force and milling temperature were examined, which provided theory basis to tool wear. Then, the tool life, wear patterns, and its corresponding mechanisms were investigated in detail through scanning electron microscope observation, X-ray energy-dispersive spectrometer, and automatic tool analyzer. By analyzing experimental results, it was found that, for an example of five-stage compressor blisk of a certain type aircraft engine, disk cutter can only remove about 50 tunnels' volume after five times grinding before wear-out failure, the tool life still needs to be greatly enhanced. The damage morphologies were delamination, thermal fatigue crack, plastic deformation, and tipping. Wear mechanisms were the synergistic interaction among adhesion wear, oxidation wear, and diffusion wear. Thermal crack and tipping were easily found for the cutting edges around the keyway. The oxidation degree of major cutting edge was higher than minor cutting edge; rake face was severe compared to flank face. The element W easily diffused into the titanium alloy, the diffusion ability of Co and C were weaker than W, and the element Ti was dead in diffusion process.