Femtosecond laser micromachining of cutting tool materials is reported in this study. A femtosecond Ti:sapphire laser with a pulse width of 25 fs, a wavelength of 790 nm, and a repetition rate of 1 kHz was used to create grooves and hole patterns on various tool materials such as high speed steel (HSS), tungsten carbide (WC), silicon nitride (Si3N4), polycrystalline cubic boron nitride (PCBN), and diamond. Grooves were created on a sample of stainless steel (SS) also to make a comparison with these tool materials. The laser parameters that are varied are polarization of the laser beam and laser fluence. For a linearly polarized beam, ripple-like periodic structures were observed on HSS, WC, SS and diamond whereas there was no ripple formation on Si3N4 and PCBN. The ripple structure was found to be aligned perpendicular to the electric field vector of the laser beam. A dot-matrix type of structure was observed for a circularly polarized beam. Further experiments were conducted by creating hole patterns near the cutting edge of a tungsten carbide tool insert. The small holes were filled with two different solid lubricants and the insert was tested in machining of steel. A comparison to assess tool wear under the same conditions is made with that of a regular tool insert. Although no conclusion can be drawn from the SEM pictures over the impact of lubrication on tool life, the observations suggest potential ways of improving lubrication during material removal.
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