Static/Dynamic Stiffness Analysis of Ball Screw Feed Systems with Different Support Configurations Considering Workpiece Mass and Placement Position

The static/dynamic stiffness of the ball screw feed system has an important influence on the machining accuracy and stability of the machine tool. To study the static/dynamic stiffness characteristics of the ball screw feed system under different support methods, a dynamic model of the ball screw feed system is established using the lumped parameter method. Then, the variation of the system’s static/dynamic stiffness is studied, and the influence of workpiece mass and placement position on the system’s static/dynamic stiffness is also concerned. The results show that as the stroke increases, the static/dynamic stiffness of the system with fixed supports at both ends first decreases and then increases, while that of the system with one end fixed and the other end floating always decreases. Comparing the two systems, the dynamic stiffness of the one with fixed supports at both ends is more sensitive to the workpiece’s mass and placement position. At the same time, as the workpiece mass increases, the natural frequency of the ball screw feed system decreases. The closer the workpiece is to the center of gravity of the worktable, the smaller its influence on the system’s natural frequency.