The modification mechanism of ionic and nonionic surfactants in ultraprecision machining of high plastic materials

Surfactants have brought about specific changes in the physicochemical properties of surface layers and chip morphologies in the machining of high plastic metals. This has been recognized as a vital strategy in improving the machinability of high plastic metals. To explore the modification mechanisms of surfactants in ultraprecision machining, microgrooving experiments were conducted on annealed copper. Anionic Sodium Dodecyl Sulfate (SDS⁻), cationic Tetradecyl Trimethyl Ammonium Bromide (TTAB⁺), and nonionic Octylphenol Polyoxyethylene Ether (OPE-10) were applied as surfactants in machining for the first time. The research focuses on the cutting forces, surface quality, and chip morphology under various applications of surfactants. The study demonstrates how ionic surfactants, SDS⁻ and TTAB⁺, enhance the machinability of metals by reducing cutting forces and improving surface quality, while nonionic surfactants OPE-10 are less effective. To explain the differences in the functions of surfactants, the modification mechanisms were studied from four perspectives: the adsorption mechanism of surfactants on the workpiece surface, the promotion of surface energy on microcrack propagation, the reduction of friction by the surface liquid film, and the influence of surfactants on the deformation zone. The results showed that surfactants with strong adsorption capabilities, good wettability, and a robust surface liquid film can yield beneficial effects on ultraprecision cutting. This research can provide insights into the applications of surfactants in precision machining of plastic metals.