y+ axis vibration

[jay R]

Help!! and not just with why I am running my cmm at 3 am on a saturday morning.

Anyhoo, my machine has taken to giving me a bit of a vibration when moving in the machines positive direction in the y axis. I have cleaned, recleaned, then cleaned one more time for good measure, my table and air bearings as best I can when just applying alcohol to the table and driving around, and scrubbing the table with lint free cloth.

The tech that came in to set our cmm up, said as a good way to check the bearings, put a little alcohol on the table and drive thru it. I did that and it left no streaks, like he said should be the case. However, on the x minus side of the tower(operator side), I see a lot more bubbles coming out around the puck then I do one the x pos side. Is this an indication of a blockage?

I have great air, with my own dedicated compressor and enough filtration to clean my air, two coallescing filters, two water traps, and the filter regulator that came on the machine.

The vibration is only when traveling in the y pos direction.

As always, thank you for your help, oh and don't try telling me you are all home for the weekend

Jay

[JamesMannes]

I don't have any experience in this myself, but my boss has related to me remedies that he has found for various maladies that can ail a CMM. One such illness is of the flavor you speak. Take off the cowling on the +x side of the machine that covers your Y axis motors and stuff. Somewhere in there should be a little white gear. Make sure that the gear is not chewed up in any area, and that it is fastened tightly.

All the help I can give you, sorry if it doesn't show you any reward.

[ag162]

Hello,
If you spray the alcohol on the table and drive the cmm forward, do it still have the vibe? Also, make sure that your air lines are not bent or kinked, as this can restrict air flow. If all else fails, you can increase the air by a cpl psi and still be ok.

A.Gore

[TRD_racing]

Jay, if your problem is not what James and AG said, well here goes. I have a Global Image 9-12-8. It is 3 years old. We are in the process of having all 3 axis’s rebuilt. All bearing, belts and pulleys. Reason for this was vibrations causing false hits and trouble taking manual hits and calibration. I was getting noises out of all 3 axes. My X-axis was the worst. I tried everything I know before we did any of this. I had every guard off the machine and still had problems. After we replaced all these items I don't even hear my X-axis. So we did the Y and are planning on doing the Z next week. My calibrations are great, the machine runs better, I am very please that machine is right again. The belt tension is really important on these machines. One of the other things the tech suggested was to change my acceleration speeds to 1500 from 2500. It slowed the machine a fraction but it very smooth now, no jerking. I run at 80% on most of my programs. Hope this helps.

[Jan d.]

What kind of machine do you run????

It varies dramatically from machine to machine. Sometimes there is some wear to the drive-train and all becomes "looser". This could be reolved in 2 ways: 1) rebuilt 2) adjust the gains.

My experience though is that very seldom the airbearings will cause these types of vibrations. It is likely in you drive train.


Jan.

[KBearden]

We recently had or B&S Xcel 15-30-10 re-hosed. Now with this service, all of the gears are replaced as well. Well get this. One of the three NEW gears produced a vibration like you are speaking of. The remedy was to put the old (6 year old) gear back in. The vibration went away. The tech was supposed to get back with me on the problem with that particular gear, but I haven't heard anything as of yet and I doubt I will.

[jay R]

Hi guys and thanks for the input. It looks like I have solved part of the problem. I removed the covers on the z, and found a small air leak. I fixed that hose by trimming it back a bit and reinstalling and about 95 percent of the vibration is gone now. I am guessing that the leak was sufficient enough to starve the air puck slightly. It also seems to have fixed another probelm that arose last week in which my z would suddenly plummet 2 inches towards the table. Talk about terrifying. My guess here is that again, the air leak was big enough to cause the z axis brake to partially engage, then suddenly release.

This is the third air leak/blown off hose in a month, am I about to have to rehose my machine? What is the ticket for that gonna be?

Just out of curiousity, what air pressure does everyone run at?

My machine is a B & S 7-10-7

As always thanks and its nice to be back on the right side of the sun again

Jay

[ag162]

Good Morning,
Yes, I would suggest replacing every airline on your cmm. This is something that you can do with a little patience and time. Take a sample of your trimmed off airline to maintenance and see if they have any like it. This is not a special item. If not, they need to order a box or a spool. You can take the trouble of measuring every line to give a length, or they can just order a cpl hundred ft. This will be a one time purchase then.

VP A.Gore