Re: [CAD_CAM_EDM_DRO] Bent Nook ballscrews ?????

Kim Lux wrote:

>A substantial amount of force would have to be greater than the pushing
>capacity of the motor so that there was never a force that would
>displace the nuts against each other. If the spring is weaker than the
>pushing force of the motor, then it will displace the backlash under a
>heavy cut.
>
>As soon as the nuts are adjusted for the maximum force the motor is
>capable of moving, there isn't any force left to move the cutter.
>
>

No, you're confusing drag with linear thrust. If the system is designed to
apply 1000 Lbs of linear thrust, you want somewhat over 1000 Lbs
of preload force between the two ballnuts. On a good ground screw,
1000 Lbs of preload will cause a very mild drag, maybe 10 Oz-In
when new, and decreasing as the screw and nuts wear in a little.
You don't have to adjust the nuts until they bind up. That could be
5000 - 10,000 Lbs of preload, and will quickly destroy the balls.

Jon