Abstract: An optimization idea is presented to improve the weak link which is identified after dynamic analysis of a machine tool. The weak link of a machine tool in different excitation frequencies can be identified by dynamic stiffness analyzing, the optimization is targeted and efficient by this method. Harmonic response analysis and modal analysis of a horizontal machining center are calculated by using ANSYS Workbench, which indicates that the column is the weakest component in x and z directions. Taking the column as optimization object, sensitivities of the nature frequency to the thickness of sidings are calculated. An optimization equation is built with the nature frequency as the goal, and the mass as the constraint condition. The equation is solved by using Matlab and optimization result of the column is obtained. Dynamic stiffness of the optimized machine tool is obtained through harmonic response analysis, which shows that under the condition that the mass does not increase, the biggest resonance peaks in x and z directions is reduced by about 6.5%, the vibration frequencies is increased by about 10%.

Key words: Dynamic stiffness, Horizontal machining center, Machine tool, Sensitivity analysis, Structure optimization, Weak link identification