A ball screw works in a similar way to a conventional lead screw, but the significant advantage of using a ball screw is that it uses ball bearings running in the helical channel to transmit the load. In high precision applications it is often necessary to translate the rotary motion from a motor to linear motion for the payload. One way of achieving this is by using a ball screw.
Ball bearings within a ball screw roll along the track in a similar way to ball bearings in a standard rotary ball race, therefore eliminating the sliding friction associated with lead screws. The ball bearings are continually recirculated through the ball nut, distributing the load and picking up lubrication along the way. Due to the use of rolling ball bearings within a ball screw, the internal friction is very low, meaning ball screws can offer a high level of efficiency and positional accuracy even at high torque and force loadings.
Ball screws can be quite complicated and high-precision devices, meaning they can sometimes be slightly more costly compared to a typical lead screw. This is due to the complex machining and assembly techniques required to manufacture them. However, if your application requires a ball screw, the greater performance generally outweighs the cost.