Removing Backlash And Increase Efficiency With Ball Screw

One of the most important parts of a machine is the ball screw. Usually many hesitant to use this particular type of screw because of the cost of replacing the ball screw when it fails. But now you could fix it by using ball screw repair that will cost less and be done faster than replacing the ball screw. Ball screws that are used in many industrial types of machinery nowadays have a long history threadless ball screw. For many centuries, the primary mechanism used to convert rotary motion to linear motion is the traditional lead screw that consists of a nut and threaded shaft. It is used because of the reliability and inexpensiveness to manufacture. However, in the late 19th century an engineer wants to reduce friction and place ball bearings in the nut threads. The result is over 90% efficiency with no backlash.

Many still rely on the lead screw in their system because it is one of the most basic linear-motion devices because of their reliability and low cost. Current advances in the latest machining also make lead screw highly precise and offer below 1-micron lead error. It is also the reason you could find a lead screw in many linear drives like aerospace controls, machine tools, a host of an industrial appliance and precision stages. But the lead screw has a limit. High frictional forces are generated by the sliding between threads of the nut and shaft. This condition makes the lead screw hard to reach 50% efficiency due to the friction that generates heat that limits the rotational speed. Not only that, but the play between the threads also produces a backlash.

But these limitations are crucial for many others, especially in high-load CNC machining. The backlash hinders servo control precision and the low-efficiency demands larger drive motors. The efforts of pre-loading to get rid of backlash will create bigger friction and greatly decrease efficiency until lower than 30%. The backlash is erased and efficiency rises to 90% when ball bearings are placed within the nut assembly and maintain contact by pre-loading. Those ball bearings additional is what makes a ball screw.

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