A lead screw or ball screw is a mechanical component used in positioning actuators to convert rotary motion into precise linear displacement. It consists of a threaded shaft (screw) and a mating nut. In a lead screw, the nut slides directly against the thread surfaces, relying on sliding friction. In a ball screw, recirculating ball bearings are interposed between the screw and nut threads, reducing friction and improving efficiency. Both types enable precise positioning, force transmission, and motion control in automated systems such as CNC machines, robotics, and industrial automation.
The working principle involves applying rotational force to the screw shaft, causing the nut to travel along the helical thread. The lead (pitch) determines the linear distance traveled per revolution. Ball screws offer higher efficiency and lower wear due to rolling contact, while lead screws are simpler and often more cost-effective.
Typical specifications for these components include nominal diameter (16–80 mm), lead (5–40 mm), accuracy grades (C3–C7 per ISO 3408), dynamic load rating (5–120 kN), static load rating (10–250 kN), maximum travel speed (60–120 m/min), operating temperature (-20 to 80 °C), backlash (0.01–0.05 mm), screw length (500–6000 mm), shaft diameter (12–50 mm), lubrication type (grease or oil), and mounting type (e.g., fixed-supported, fixed-fixed). Materials commonly used include carbon steel, stainless steel, and alloy steel.
These values are reference ranges and must be verified with the manufacturer for specific models and applications. Standards such as ISO 3408 provide guidelines for dimensions and accuracy, but compliance must be confirmed by the supplier. Always consult the legal manufacturer or supplier to ensure the selected component meets your requirements.
Rotational force applied to the screw shaft causes the nut to travel along the screw's helical thread. In lead screws, the nut slides directly against the thread surfaces. In ball screws, ball bearings roll between the screw and nut threads, reducing friction and enabling higher efficiency and precision. The pitch of the thread determines the linear displacement per revolution.
