Top-down Design Method for Static Stiffness of Vertical Coordinate Boring Machine Tools

The entire machine static stiffness is one of the critical metrics for assessing the machining performance of CNC machine tools, reflecting the machine's structural capability to resist relative elastic deformation between the tool and the workpiece under steady-state cutting forces. Adequate static stiffness is the fundamental starting point and target for the design of CNC machine tools. Currently, domestic static stiffness design predominantly relies on finite element modeling and simulation analysis to compute the three-dimensional static stiffness at the machine's terminal. On this basis, this paper took the precision vertical coordinate boring machine as the research object. Based on this, a static stiffness model of machine tool was established using multibody theory, a characterization method for the static stiffness coefficients of structural components was proposed, and the relationship between the entire machine static stiffness and the static stiffness of individual structural components was clarified. With the entire machine static stiffness required by users as the target, structural component static stiffness contribution analysis was conducted using experimental design methods, thereby achieving entire machine static stiffness matching and obtaining the static stiffness values of each component. By constructing a neural network model, a mapping relationship between structural component static stiffness and its dimensions was established, completing the design of vertical coordinate boring machine tool structural component dimensions. Finally, the accuracy of the theoretical results was verified through static stiffness experiments, forming a systematic forward design method for the entire machine static stiffness of machine tool. The proposed design method can guide the top-down design of machine tool static stiffness and has a certain practical value.