SL-400 BMC Lathe

[ceilingwalker]

Good day all. I have a Mori Seiki Lathe, SL-400 BMC. This machine has been used for the past 5+ months without way lube. The lube alarm was never addressed until a work order came in. I replaced the pump, cleaned metering valves (all of them) and set the lube timer to oil the heck out of the ways. I'm an electronics tech and not a mechanic (yet). We have about .007" backlash in X-axis and all of my attempts to adjust parameter 1851 have had no effect. I have a few questions, please:

1. Do I have to turn off control between changes to backlash for them to take affect?

2. When I jog X back-and-forth and look at the ball-screw I can see the ball bearings moving nicely in one direction, however, when the ball-screw reverses direction those same ball bearings don't move at all. Does this mean that I have lost my pre-load?

3. If I have lost the pre-load, how can I fix it?

Thank you much for the advice you guys have provided me since i've joined, I really appreciate it.

[underthetire]

1st, remember it the off cycle of the pump that actually oils the ways. The system pressurizes the manifolds pushing the plungers to fill them up, then when the pressure releases they meter .16CC of oil to each line. I never clean the dester ( manifold) units, not saying it can't be done, it's just usually the seals swell up inside and don't work correctly. .007 backlash is way too much, period. No need to cycle power with adding backlash comp, but it will be a huge number to comp for .007. If the machine has not had oil in a while, the gibs need to come out and be checked as well. You need to also check ballscrew end play to figure out how much backlash is in the screw, and how much is in the ball nut. If you try to re- preload the screw with bad balls in it, the screw will just fail at this point.

[ceilingwalker]

You need to also check ballscrew end play to figure out how much backlash is in the screw, and how much is in the ball nut. If you try to re- preload the screw with bad balls in it, the screw will just fail at this point.[/QUOTE]

How do I do it? Also, how does one re-preload bearings? Thank you

[underthetire]

See if this helps. As far as re-preloading, you would first have to take the screw out, replace all the balls, then grind the shim until you get proper pre-load. I would just buy a new one or send it to a re-builder. I've done one in the past thats still running today, but it's a lot of work if it doesn't last.

[underthetire]

Oh, and once you pull the X axis motor your going to have to re-zero the X axis, using the zero point set mode in the custom screen.