Optimization of laser surface texturing for improved tribological performance in engine valve trains

Abstract This study investigates the influence of laser surface texturing (LST) on tribological performance by optimizing texture geometry, orientation, and density under varying lubrication regimes. AISI 5115 steel surfaces were textured with triangle, ellipse, and circle patterns at 5–20% densities using a femtosecond fiber laser. Tribological tests (pin-on-disc) under dry, starved, and lubricated conditions (100–400 rpm) demonstrated that a 15% density ellipse texture (aspect ratio 0.1, 45° orientation) reduced the coefficient of friction (COF) by up to 72.22% and wear by 93.18%. Surface analysis (SEM, LSCM) confirmed improved load capacity and lubricant retention. Engine bench tests on textured tappet shims showed friction torque reductions of 7.35–11.56% (300–700 rpm) and temperature-dependent COF improvements (9.55–20.48%). The study provides a systematic approach for optimizing LST parameters to enhance wear resistance and friction performance in mechanical systems.