Shan Li, Seyed Hamed Hashemi Sohi
The static-dynamic behaviors of ultra-precision five-axis machine tools are the core factors to ensure sub-micron-level machining accuracy. This study establishes a detailed finite element model of an entire machine based on the ANSYS Workbench platform and conducts in-depth research on the static-dynamic characteristics of the entire machine of the ultra-precision five-axis machining center by using the finite element analysis(FEM) method and combining the principles of statics and dynamics. By constructing an accurate finite element model, the stress distribution, deformation, and modal vibration characteristics of the entire machine, especially the key parts, such as spindle box, crossbeam, column, and guide rails, under complex loads such as gravity and cutting force are simulated. The static analysis reveals a maximum deformation of 0.17 mm in the spindle box and the column, and the maximum stress is 58 MPa (at the Z-direction guide rail contact point), which is lower than the allowable stress of Q215 steel (195.5 MPa). The modal analysis extracts the first six natural frequencies (50.683 - 175.91 Hz), and the low-order vibration modes are mainly the Y/X-direction swing of the column, revealing the weak stiffness links. Based on the analysis results, a parametric optimization method was further adopted to optimize the structure of the weak components: the base, the column and the spindle box. This significantly enhanced the overall stiffness, reducing the maximum deformation to 0.039 mm and the maximum stress to 45MPa. The first six natural frequencies were all greatly increased (the first one reaching 85.548Hz). These findings provide valuable insights for machine tool structural enhancement and performance optimization.