Suddenly, the Z axis is noisy

[Vern Smith]

TM-1P built January 2006. It's a grease machine and has been greased regularly. The Z axis makes a wine or groaning noise that can only be heard during rapid moves, like tool changes. It is much more noticeable from the back of the machine and it does it not matter where the spindle is positioned. Any move from any position in rapid generates the sound. It's not one of those terminal sounding noises but started yesterday out of the blue, no discernible build up. I let the machine cool down over night and found the noise to be exactly the same today, no difference in the sound level.


It does not sound like sheet metal, not tinny at all. To me it sounds like a hydraulic pump or actuator. The local HFO is a 5 hour round trip away so I try to fix things my self if possible. No big time pressures but can't ignore it. I know several of the fellows on this forum are machine technicians and hope this is a recognizable condition.

I did pump a couple squirts of grease into the two grease fittings on spindle cover but it made no difference. I would appreciate any pointers or similar experiences.

Vern

[HuFlungDung]

Vern,
I had an old lathe that made a clacking sound whenever the spindle was commanded to stop. I put a couple of shots of grease in a grease fitting there, and lo and behold, it also made no difference. So that's fairly similar, huh?

Is yours one of those without a counterweight? What is the Z axis servo motor load look like? Not that I'd know what it should be, but someone else may recognise if the % load seems abnormal.

[Geof]

This may be something that you just live with.

I have a VF0 dating from 2000 and the X axis started groaning around mid 2005 or 2006, I cannot remember which. I had the local Haas tech in to listen to it without getting any good suggestions. We checked the backlash and as far as we could tell it was fine. We checked the oil feed and it was fine; I even rigged a system to pump oil into the ballnut manually until it was leaking out the ends and it made no difference to the noise. So we kept on using the machine figuring why not so long as parts come out within tolerance; which they did.

Eventually the noise got so loud it was scary so I went into the Parameters and halved the rapid speed on the X axis to make it a bit quieter; this was about 18 months ago.

It still groans and has not got any louder, parts still come out within tolerance and when we checked the backlash about a year ago we still couldn't find anything. It interpolates holes that are round to better than 0.0005".


The moral of my tale is that you could spend money getting a new ballscrew and nut installed or you can just live with it if the machine still puts out good work.

[Vern Smith]

We are having the usual summer afternoon SW Florida thunder and lightening at the moment so I have the plug pulled on the mill. I'll do some checks this evening along the suggestions you fellows have made. I did not notice any problems with the machines Z accuracy yesterday but I'll do some specific checks for Z repeatability and look at some spindle load numbers. The problem is I don't have a base line for what they should be. You can bet I will in the future

Vern

[HuFlungDung]

It is possible for servo motors to make noise if there is some small amount of error in the PID filter settings. I'd suggest perhaps phoning Haas tech support and ask them if there is some sort of a small range of adjustments that you could try, and they should be able to give you the numbers that go with the necessary settings.

Now why your motor/amp would suddenly be acting up could be due to aging components. I suppose you could try swapping an amp to see if the problem moves to a different axis.

[Vern Smith]

I ran the checks previously discussed, the Z positioning seems fine with several checks. The X & Y axis show 68 to70% load when sent home with G28, the Z axis shows 50% ( up ). I have a friend with a TM-1P and I'll see what kind of figures he gets. I'll call Haas tomorrow and see if they have any suggestions. Maybe they can listen to it over the phone

[Vern Smith]

I talked to a service tech at Haas a few minutes ago and he said it was more then likely the bearing pack right under the motor. His recommendation was not to bother with it until it got so noisy that I couldn't stand it or until the quality of the finish deteriorated. I guess all I can do is keep an eye on things.

He sounded like this was not an uncommon problem, as a matter of fact I had not finished my rehearsed description before he made the diagnosis. Of course, I've known some mechanics in my day who could diagnose over the phone and the results were not always so good

His confidence was reassuring however.

Vern