The speed at which the screw begins to encounter bending vibration is called the critical speed. The calculation of the critical speed takes into account the diameter and length of the screw and the type of end bearing supporting the screw. In this calculation, the length is defined as the unsupported length of the screw. If the ball nut is not preloaded, the unsupported length is the distance between the end bearings. If the ball nut is preloaded, the unsupported length is the distance between the ball nut and the small rigid bearing support. From the equation, you can see that the critical speed is inversely square to the length that is not supported. In short, by halving the unsupported length, Ball screw pair The critical speed of the system is increased by four. Therefore, the critical length of the support method is not efficient. But how to reduce the unsupported length of ball screw without sacrificing stroke length? Long distance travel and high speed: you can have both ball screw support to solve this length speed dilemma. These floating supports (usually used in groups 2, 4 or 6) are located on one side of the ball nut and connected in such a way as to allow them to extend equally spaced on one side of the ball nut, if the nut moves in the opposite direction, proportionally reducing the unsupported length. In the direction of the ball nut travel, the support member is stacked at the end of the screw to provide small interference to the travel. According to the critical speed equation, adding a group of ball screw supports (one support on both sides of the ball nut) will make the critical speed of the screw increase by four! Cutting, wiring, and other operations in metal manufacturing and woodworking are common applications for ball screw support because they require high thrust and good positioning accuracy, while moving at high speeds for long distances.