Preload is the controlled axial force applied to a ball screw during CNC machine tool operation. It eliminates axial clearances and minimizes backlash, thereby enhancing the screw's stiffness, positioning precision, and servo responsiveness. So, how does adjusting preload influence ball screws in CNC systems?

Enhancing Axial Stiffness: Preload amplifies axial stiffness, enabling ball screws to better withstand deformation from cutting forces (e.g., from high-speed spindles) and reaction forces from linear guideways. This diminishes errors in servo motor tracking.

Thermal Considerations: Elevated preload levels can heighten friction, increasing nut temperature and inducing thermal elongation of the screw. Excessive preload escalates motor torque demands, reduces machining efficiency, and may truncate the lifespan of ball screws due to overheating.

Load Matching Strategies: Preload ought to correspond to the machining center's cutting load profile. Proper preload compensates for deflection caused by cutting forces and preserves precision. However, under high dynamic loads (e.g., turn-mill applications), excessive preload accelerates fatigue and flaking in ball screws.