Excessive noise only in x axis

[Toolguy67]

Hi guys,

I have Hardinge/bridgeport XV710 that is giving us alot of chatter when side milling........but only when cutting in the x axis. Doesn't matter if it's a rough or finish cut it still squawks to some degree. Not excessively long tools, good endmills, type of stock doesn't matter, and yes the speeds/feeds/sfm are appropriate. A .750 variable helix endmill taking a .01 cut .75 dp at 100,200, or 300 sfm with a .003-.005 chip load without issues........but it won't

If I machine a square block and program for 500 sfm with a .500 varimill .5 dp .03 rdp it will be fine cutting along the y but squawks/chatters very loud in x. I have tried solid holders, collets, stubby set ups.......same thing. I thought spindle bearing....but why only x axis. I also considered backlash, but it was checked within the last year.

Anyone care to enlighten me on what they have experienced ?

Thanx

 

[PaulT]

Most likely your x axis thrust bearings are shot.

To check them you need to measure the slop of the x axis ballscrew relative to the table.

Set up an indicator with the base on the table and the indicator on the end of the x lead screw.

Push back and forth hard on the table and see how much slop the indicator shows, anywhere close to 0.001" or more is likely bad thrust bearings.

If the thrust bearings are good now measure how much slop you have from the table relative to the spindle, ie move the indicator tip to the spindle surface. If you see slop there your ballscrew could be worn.

Also check for slop in the power transmission hardware from the x motor to the screw.

These are good checks to to on all you axises even when the machine is running well, write down the numbers and you'll have something to compare against when the machine starts acting up.

Good luck-

Paul T.
Valve and Chassis Spring Tester Home Page - Power Technology Valve and Chassis Spring Tools

 

[zero_divide]

Sound more like worn out linear ways.
If Backlash is good and no noise when running w/o load then your table must be moving around more than it should

 

[apoc_101]

yea I was thinking the same regarding ways... although thrust bearings could be a consideration if the machine was ever crashed the right (wrong) way.

 

[Toolguy67]

Thanx fellas. I will definately check this stuff out. Pretty sure on the backlash but I will check again along with thrust bearings.

 

[toolmaker96]

Is your machine a Box or linear way?
Is the part cutting a parallelogram? If so it is most likely worn linear ways, or trucks. If box way, loose y axis gibbs.

 

[Toolguy67]

Is your machine a Box or linear way?
Is the part cutting a parallelogram? If so it is most likely worn linear ways, or trucks. If box way, loose y axis gibbs.

Linear and it's cutting square....... The machine is a 2006 also

 

[Co2 mech]

Thrust bearings, screws, ways, gibs all good things to check. Add to the list reseating the encoder cables. We had a laser raising hell on the turns and reseated the cables and all was good.
Regards

 

[Toolguy67]

Did all the checks except the encoder. Have a little backlash in x and noticed whith a tenth indicator that when switching direcions in handwheel mode, set to tenths, it takes at least five "clicks" when switching directions, before th NEEDLE moves . Ballscrew is turning. But the push test only shows about .00015 with all the mucsle I have. This was in addition to the above tests.
Thrust bearing check looks good.
I checked z for play.....mag base on table and needle on z axis. pushing z axis front to back-good. Side to side just over a thou slop- not so good....
I did isolate the spindle from the z to eliminate loose bearings, spindle cartridge, etc.......... indicator on spindle, then on just z axis. Spindle seems fine.....same indicator travel both spots.

I also set my base on the table with the needle on the front side of the x way. When I moved y , i got .0005 movement which kinda makes me think table is cocking a bit and x ways or trucks mebbe a little worn but not sure.

Gonna do some cutting tests.....circle and squares

 

[PaulT]

Toolguy, it doesn't sound like your seeing enough slop anywhere (ie you're seeing 0.0005 or so) to cause the chatter amount you described, let us know what you find as you keep looking at the machine.

Perhaps the x encoder is flaking out, its not too hard you could swap it with the y encoder to see if the problem moves with the encoder.

Paul T.

 

[Toolguy67]

Toolguy, it doesn't sound like your seeing enough slop anywhere (ie you're seeing 0.0005 or so) to cause the chatter amount you described, let us know what you find as you keep looking at the machine.

Perhaps the x encoder is flaking out, its not too hard you could swap it with the y encoder to see if the problem moves with the encoder.

Paul T.

Thanx Paul, I will. Mebbe I can get mainteneace to switch encoders while I'm keeping other stuff running. See if I can make this whole TEAM concept work for me lol

 

[PaulT]

One other thing to check is any slop in the drive system from the servo motor shaft to the ball screw, ie couplers, pulley hubs, belts,etc.

 

[hesstool]

I thought spindle bearing....but why only x axis.

It's been about 18 months or so when the spindle bearings died on my XV 710 and chatter clearly became a problem before I had it rebuilt. However, the only noise was from the spindle and not from any of the axes.

So it doesn't make any noise while running the X and Y together? And is this a problem only when cutting or does it make noises while rapiding in X only?