Problem- 98 VF2 Y axis GROWL noise

[LakesideMachine]

This moring was a new one....
The Y axis started making a horrible noise as it moved almost sounded like gravel in the ways!

We shut it down, stripped the covers and took a alook.

the screw moved nice and smooth and the ways looked normal and smooth.

firing it up again, the Y servo started making noise. i grabbed the screw and could feel it twitching back and forth as if it is fighting a loose encoder or somethijng. if I turned it one way the servo would growl worse.....the other way it went away.

Whats the cure for this? can this be as simple as something loose like the encoder plate?
if this is an easy fix....how do we go about it without tearing half the machine apart??


Thanks fellas!!!

[Haas__man]

I think your problem will be a faulty servo amp (Y axis drive board).
If you open the electrical cabinet.
Make sure power is turnd off.
Wait Approx 15 minutes(to make sure high voltage is discharged from vector drive)
To double check that voltage has gone, look at High voltage LED on vector drive.
The servo amps are at the left side of cabinet, and about half way up.
They are gold.
The left hand side one should be the x axis.
next one along is the y axis.
Swap the x and y servo amps.
If the servo amp is faulty then you should now have a noisy x axis.

Hope this helps.

[LakesideMachine]

DANG...thats exactly what it was.......


i have a spare amp for the A axis.....i'll see if i can swap that out to get me running again.

Thanks for the help!!!!!!

[Pondo]

Before you go and spend a bunch of $, try this:
There are 4 bit switches in the parameters for each axis that can be adjusted. They are Low pass 1X, low pass 2X, Dfilter X8, and Dfilter X4. Change them 1 at a time (either to a 0 or 1) and it may get rid of the growling. My mill had a similar issue in the Y and Z axis. Changing the parameters took care of it.
Can't hurt and it may save you $.
(Don't forget to change setting 7 to allow the parameter changes)
Parameter 1=X axis
Parameter 15=Y axis
Parameter 29=Z axis

Hope it helps.

[abhthree]

Good morning,

The X-axis on my VF2 started growling the other morning and the machine is alarming out with a Alarm #103 - X Servo Error Too Large.

We called the Haas repair and they suggested that we might have a bad servo amp. This was also the suggestion mentioned on a previous forum. I switched the servo amp(gold colored thing) with the 4th axis amp and the problem still remains.

The load monitor is very high on the axis even when it is stationary.

Any suggestions on what my problem is? Could it be bearings? Could it be a chip in the ballscrew? Do these ballscrews wear out? The machine is a '99 Haas VF2. We just replaced the spindle, so I know that sometime stuff needs to be replaced.

I called Haas and they "put us on the schedule". It sounds like their techs are super busy right now. I can order parts and put them in myself, however, I need help diagnosing the problem.

Thank you for your help,

Arnot Heller

[Al_The_Man]

As a general rule for that symptom, it can be either the servo cannot arrive in position due to large friction etc, or the loop gain parameter is high.
Al.

[double a-ron]

I had a similar problem on my mini mill. The y axis made allot of noise when sitting still and produced a terrible finish on parts. The Haas guy came out 3 times to fix the problem. The first two times he said it was the coupler which sounded wrong but what do I know. The third time he came out he pulled the servo out, put it on the table and powered it up. It just sat there shaking and vibrating. So he assumed the same thing your thinking, that it was the amplifier. After putting a new one in and powering up the servo it still shook and made noise. So now he's thinking it's the servo. Replaces the servo same problem. Now there's a new servo, and new amp in and the exact same problem is still there. He gets on the phone to Haas and explains the problem and after another hour or so the guy on the phone tells him to change the low pass filter settings in the parameters section. Sure enough that solved the problem. Interesting note, a few months latter when we got our hrt 160 rotary table, same problem, same solution.

[abhthree]

Pondo,

Used your parameters and it fixed my X-axis growl. Thanks a lot. It also reduced the servo load. It's cool, but a little weird. Can anyone explain why this works? What am I changing?

Arnot Heller

[abhthree]

That definitely worked. THanks a lot. I read the post by Pondo, maybe someone can merge these two posts. I would love to know why that works, I can't figure it out.

Thanks everyone,

Arnot

[JoBwan]

Originally Posted by abhthree That definitely worked. THanks a lot. I read the post by Pondo, maybe someone can merge these two posts. I would love to know why that works, I can't figure it out. Thanks everyone, Arnot

Thanks for sharing this information guys! Great to see help is always lurking around the corner!!!

[Al_The_Man]

I merged both threads.
The D filter is most likely part of the PID tuning loop which affects the gain.
Al.

[abhthree]

We ran for about an hour and now the problem is back. I don't have any of the twitching that it mentions earlier in this thread. It runs for a while and then the load on the axis goes way up. Could it be a mechanical issue? When I try to turn the ball screw it is tight.