Ballscrew backlash

[njlwilliamson]

Hi,

I've just done a bit of maintainace of my Novamill and I checked the backlash on all three axis. X and Z were fine, 0.01mm ish, but the Y axis was way out. I measured the backlash as 0.05mm!
I checked the belts and pulleys. The ballscrew rotates with the stepper but the ballnut doesn't move untill I turn the ballscrew pulley five degrees or so. My guess is the problem is with the ballnut/screw. Does anyone know if there is a way to adjust the preload in the nut or is the nut and screw on the way out?

Cheers.

[flyingmike]

Morning! Have you tried measuring it with the nut at different points along the screw incase there is any localised wear? and also check for movement in the bearings as the entire leadscrew could be moving.

I`m not sure if the ballscrew nut is preloaded, I suspect it may not be, in which case 0.05mm is not that bad.

[angel-tech]

it could be a bit of play in the bearings.

[njlwilliamson]

Hi. There was a bit of play, axial, of the screw. I snugged up the star nut on the end of the ballscrew and now the backlash is down to 0.02mm. Thanks for the tips guys!