[exhaustgases]

When moving the MPG, in tenths it jumps back about.0005 when reversing direction. And about .002 in the .001 range. Its was real good till the guy on other shift crashed it. Any ideas why? Whats the quick fix?

[txcncman]

The quick fix is fire the guy that crashed the machine and use his salary to hire a machine mechanic to come fix the machine.

What do you mean "jumps back"? Does it "jump back" on all axis?

[exhaustgases]

The quick fix is fire the guy that crashed the machine and use his salary to hire a machine mechanic to come fix the machine.

What do you mean "jumps back"? Does it "jump back" on all axis?

There is no one in this business that has not crashed a cnc. That is that has any time running them. Everyone screws up its called being human. Fire the guy and hire one thats ten times worse, right? I'd rather this guy on the machine than some of the other screw balls that I have worked with in the past. Maybe some goof that likes to change everything I have done on a program or setup. Or leaves a crash for me, like Z-12.0 into the fixture etc. And then has to give me a rash when I come into run it. Been there done that. Besides where I am at there are no machinists to hire now, any good ones are working.

If you have a tenth or thou indicator on whatever on the pallet, you move the X mpg one thou in the plus direction, zero the indiactor, then click x minus one thou it jumps 2 thou, or if its on the tenths it jumps .0005.
Like it is over compensating, one tech said the screw lost its tension and shrank, thus tightening up. I can comp the backlash and make it do the right thing, but it does not want to zero when going past zero and comming back in the first direction.
Meaning you zero say going X plus, back up then come back to zero it will be off some, forget how much. But it didn't have any extra movement clicking back and forth on either .001 or .0001 resolution, meaning it moved the plus and minus just fine .0001 either way meaning no backlash.

[txcncman]

Well, I could see a combination of problems. If the ball screw nut was binding it could be creating a torsional spring action on the ball screw itself causing some problems. The other is gibs binding and causing a longitudinal spring action in the ball screw. Either way, now you are dealing with mechanicals of the machine and probably no way to work around it by changing any of the machine control settings.