Optimization of spindle system first natural frequency values using response surface methodology and analysis of variance

The object of this research is the dynamical performance of horizontal lathe spindle systems, which encounter challenges related to vibration and structural integrity during high-precision machining. In particular, the study aims to improve the system’s dynamic performance by raising its first natural frequency to minimize chatter and bolster its capacity to endure operational stresses. The process of optimization was done by utilizing Response Surface Methodology in conjunction with Analysis of Variance, two methodologies that are acknowledged for their efficiency in statistical analysis and experimental design. Modifications were made to the spindle design in two stages: first, the rear bearing location (located at the end of the spindle opposite the chuck) was optimized, and then the shaft geometry was adjusted to improve natural frequency and stress resistance while keeping the overall mass of the system the same. The optimized design achieved an increase in the first natural frequency (from 529.47 Hz to 852.52 Hz) and an enhancement in stress capacity (from 250 MPa to 48.98 MPa), as confirmed by ANSYS V19 simulations. By shifting up the value of the first natural frequency, chatter is less likely to occur. This leads to more stable performance and better machining accuracy under higher operational loads. These findings are important in precision machining applications, where vibration control and structural integrity are critical to performance. The paper concludes with a detailed comparison between the optimized and non-optimized models, along with an evaluation of the influence of bearing stiffness on system dynamics. The numerical improvements highlight the effectiveness of both Response Surface Methodology (RSM) and Analysis of Variance (ANOVA) in optimizing mechanical system performance