Enter the basic static load rating, average axial load, the average number of revolutions, and service factor into the calculator to determine the ball screw life.

Ball Screw Life Formula

The following equation is used to calculate the Ball Screw Life.

BSL = 10^6 / (60*N) * (C / (P*f) ) ^3

  • Where BSL is the ball screw life (hrs)
  • N is the average number of revolutions (rpm)
  • C is the basic static load rating (daN)
  • P is the average axial load (daN)
  • f is the service factor
    • typically 1.2-1.25 for normal operation

What is a Ball Screw Life?

Definition:

A ball screw life is defined as the total number of useful operational hours a ball screw will last at a given axial load and rotation rate.

How to Calculate Ball Screw Life?

Example Problem:

The following example outlines the steps and information needed to calculate the Ball Screw Life.

First, determine the average RPM. This ball screw will run at an average RPM of 60.

Next, determine the basic static load rating. This ball screw is rated for a static load of 100 daN.

Next, determine the average axial load. The average axial load is measured to be 60 daN.

Next, determine the service factor for the operating conditions. This is considered normal operating conditions so the service factor is 1.2.

Finally, calculate the ball screw life using the formula above:

BSL = 10^6 / (60*N) * (C / (P*f) ) ^3

BSL = 10^6 / (60*60) * (100 / (60*1.2) ) ^3

BSL = 744.21 hours