Scroll Support Dual-drive Linear Feed System Dynamic Performance Analysis And Testing

With the development requiring high speed, high precision and good stability of CNC machine tools, application of feed systems equipped with double ball screws is gradually increasing due to its good vibration resistance, high rigidity and rapid system responsiveness. By taking typical double-screw-drive linear feed system as study example, its dynamic characteristic was studied from the perspective of theoretical modeling, finite element analysis, optimization and experimental verification, the advantage of the dynamic characteristic was revealed and the best installation combination of screws and guide rails was proposed. The research results were applied to design horizontal machining center’s linear feed system, by conducting modal test on the model machine, the feasibility of the design results and the validity of the finite element analysis were verified.Firstly, by taking single-screw-drive feed system and double-screw-drive feed system as the study object, two-degree-of-freedom vibration models were established, and further calculated natural frequencies. It proved that the frequency of double-screw-drive feed system were25%-30%higher than the single-screw-drive feed system, even though the diameter of double ball screws was15mm smaller, which verified that double-screw-drive feed system had better ability of improving rigidity and restraining vibration.Secondly, the finite element analysis models of the two systems were also established, vibration modes, natural frequencies and amplitude-frequency curve were obtained by means of modal analysis and harmonic analysis, and the advantage of double-screw-drive feed system was demonstrated from the perspective of finite element analysis.Again, finite element analysis models of simple double-screw-drive feed system were established. Considering the influence of ball screws’ span and guide rails’ span, modal analysis were carried out, the best installation combination of screws and guide rails was proposed based on the analysis results and the vibration models.Finally, the analysis and optimization results were applied to design horizontal machining center’s linear feed system. By conducting modal test on the model machine and comparing the experimental result and analysis result, the relative errors of corresponding vibration frequencies were controlled within8%-18%, which verified the feasibility of the design and the validity of the finite element analysis.