Research on Friction Compensation and Dynamic Performance Improvement of the Feed System in CNC Gantry Milling Machines

Taking the GLU28×40 series CNC gantry milling machine as the research object, this study focuses on the typical problems of low-speed stick-slip and commutation consistency fluctuation of the feed axis, and conducts research on friction characteristic identification and compensation tuning of the feed system. On-site identification is carried out using ISO 230-2 laser interferometry and VDI 3441 statistical indicators. A friction compensation and parameter optimization path constrained by backlash convergence, non-deterioration of repeat positioning accuracy, and improved dimensional consistency of trial-cut parts is proposed, and a repeatable closed loop is formed via friction compensation and servo parameter tuning. After compensation and tuning, the flatness of trial-cut workpieces is improved from 0.021 4 mm to 0.001 3 mm, which verifies the contribution of nonlinear friction suppression to dynamic performance and machining stability.