X axis servo gain? issue?

Hey guys,

Another little issue with my big girl (ST30 ATC M/C - T3 controller). There seems to be some sort of gain issue with the x axis servo... i'm guessing :P

here's how the issue presents - this is a finished taper cut, note the lines on it:


When i pulled the X axis encoder/belt cover off, i noticed it was shuddering, I assume trying to land itself in the correct position, you can also feel the shuddering when jogging the x axis.

[video]https://photos.google.com/photo/AF1QipMmsV1Ww7yp4ReiPP0btgCleirgp_AOSVouY9nj[/video]

I'm sure it could also be a mechanical issue, but seems to me like it's trying to drive too far or not far enough and constantly trying to correct if that makes sense? I may be miles off because i don't really know f all about servos

Cheers,
Trav

so it was annoying me enough that i thought i would have a bit more of a dig mechanically (i know mechanical stuff more than electrical stuff).

First things first - undo the 3 screws holding the encoder on and lift it straight off... WAIT A MINUTE!?! the grub screws in the flex coupling from the ball screw to the encoder weren't even done up. Encoder back on, grub screws done up and tada - good surface finish on my taper.



i'm glad it was something so simple!

good observation skills