Is there a way to take play out of Z axis?

[aadrew10]

My mini mill makes a sound i can describe as clicking when the z axis starts and stops. I only hear it when I have it set to .1 or .01 increments. It almost seems like something needs to be tightened to remove a little bit of backlash.

Any ideas?

Thanks

- Andrew

[awesome83]

Does it make the same sound during a program? I wouldn't trust the sound the machine makes during handle jog, it can be very abrupt sounding.

Do you have backlash in your z axis?
You can set up an indicator on the head stock, and push up and down and see if returns to zero. Lost motion. max .0002"

Then with the same indicator set up run the z up 1", back down 0.9", then down 0.1" with a feed of 50 IPM, then M99 and see if the z repeats.
You can increase the 1" to 5" or something if you like and possibly run at a rapid, but make sure that you feed at least the last 0.1".

You can check your ballscrew bolts, also the mounts to the casting. If the bearing thrust pack is wornout you will also get backlash. also if the ballscrew is worn too. most likely the thrustpack.

The Z is hard to check for backlash since you have to hold the spindle head up. X and Y is much easier. Always check push/pull backlash with the servos on.

[mactec54]

aadrew10

They all make that noise, It's the bearings on the linear slides that make that sound,& the not smooth servo, it does not affect the machining, If you were to change them for better rails/bearings with a higher preload, then those noises would mostly go away

[aadrew10]

I apologize for the very very late reply. The sound happens during programs also. The mini mill at school is the same year, and does not make the sound I am hearing. The VF2 and TM1's do not make this sound either. If the ball screw had developed some play, is there a way to tighten it up? Are there instructions anywhere that detail how to check ballscrew bolts and casting mounts? The sound only happens when the Z axis is starting or stopping, not during constant motion.

[Wizzard of H]

There is another source of a sound like this.
That is the brake internal to the Z axis servo motor.
The coupling from motor shaft to brake is something like a spline.
It is not perfectly rigid.
If you can hear this come distinctly from the motor when jogging 0.1 steps, it is almost certainly the motor.
It does not cause any harm and there is little that can be done to make it go away.
It is how the motors are built.

[Donkey Hotey]

Are you sure this isn't a matter of acoustics? How low is the ceiling above your machine vs the ones at school? The ceiling above my VF-2 is much lower than the VF-5 at work. They are identical 2-speed, 10K spindles. I hear a lot more gearbox noise and other strange things on the VF-2. I'm pretty sure it's just the normal noises reflecting off the lower ceiling.

[Machineit]

I doubt that you have play in the ball screw, but even if you did you would never hear it. Even with the counter balance in place there is still considerable weight on that nut.

Maybe guarding?

Mike

[aadrew10]

I will get an audio or video clip up shortly.

[aadrew10]

Here is the video with clear audio of the sound I am hearing. What could it be?

YouTube - ‪HAAS‬‏

- Andrew

[Geof]

All my Minis sound like that when you jog the Z axis. According to my Haas tech it is what Wizzard of H says, the brake on the motor.

[aadrew10]

Cool. Thanks Geof. I feel better now.

- Andrew