[brianbonedoc]

Anybody have any ideas why I am getting such bad squealing in the x direction? I think my gibs are fine as I've had this prob for a while and have snugged em all up. Btw- it's a novakon pulsar stepper.


This cut is w a new 3/8" 4fl carbide EM in 1018 steel. DOC=0.22 WOC=.0375(10%) and rpm= 2300 (about 250 sfm). This is dialed way back from hsmadvisor just to get a cut that doesn't scare the heck out of me.

[Jim Dawson]

Spindle bearings maybe? I had that problem with mine and a rebuilt spindle fixed the problem.

[brianbonedoc]

Jim - good thought. But wouldn't that cause the problem in all directions? My Y moves sound great, when it turns to X moves - all hell breaks loose!
Was thinking axis thrust bearings?

[Jim Dawson]

That is exactly the same symptoms mine had, pretty much only in the X axis. I wild guess is that it takes some time to build the resonance and the Y cuts are normally much shorter.

Thrust bearings could be the culprit, maybe try snugging them up a bit?

[brianbonedoc]

Thanks Jim - I will have a go at em. I have messed with them before to no avail. Will post back prob tomorrow w/ results.

Thanks!

[brianbonedoc]

Jim - does this give a clue? I have these swirl marks on my pocketing op.

[Jim Dawson]

That looks like a dull cutter. I would say not enough coolant, but I saw your video and you're pouring the coolant to it, so that's not a problem.

Those marks are normally caused by a chip getting stuck under the end mill, many times caused by a chip in the point if the cutter. Look at the cutter with a magnifier and inspect the tips.

[brianbonedoc]

It was a brand new cutter, I actually broke 2 of the 3/8" ones during this part. Not happy. I think this machine has gremlins. . .

I will check the thrust bearings tomorrow if I have time.

Thanks for your tips!

[Jim Dawson]

Maybe just adjusting the feeds and speed on the fly would be helpful, if that's possible on your machine. You can feel and hear when the machine and cutter are happy.

[brianbonedoc]

So I took the x axis side apart and found that the angular contact bearings were installed (by me) in the same direction- rather than opposite as they're supposed to be. Then I tightened down the preload and this really removed the play that was there. Before I could rotate the ball screw about a 1/16th of a turn before it engaged and moved the table. Now there's no play.

I did a quick adaptive test cut w a .25 2 for endmill at 5200rpm and 10% woc at 45ipm and it sounded so smooth. It's still a little too early to tell, but so far results are promising.

[Jim Dawson]

So I took the x axis side apart and found that the angular contact bearings were installed (by me) in the same direction- rather than opposite as they're supposed to be.
.

OOPS! Happy to hear it's working now. That was an inexpensive fix. :cheers:

[upnorth]

I'll be watching this thread. My mill a torus pro stepper has being doing this since it was new when cutting steel. I does it in both x and y. Varying the cut only changes the pitch of the squeal for me but its always there. I have had the mill in storage since January and will be getting back to it in a week or so. I'm really looking forward to finding a solution. The one thing it does well in steel is a boring type tool path. Went through the steel like it was butter. When profiling it squeals like crazy.

[popspipes]

Jim - does this give a clue? I have these swirl marks on my pocketing op.

I have these swirl marks when cutting steel, I think its bits of steel sticking to the cutter cutting lip, using some oil on the finish cut helps. Coolant is good for cooling but in the lube department it is lacking.

[upnorth]

So I took the x axis side apart and found that the angular contact bearings were installed (by me) in the same direction- rather than opposite as they're supposed to be. Then I tightened down the preload and this really removed the play that was there. Before I could rotate the ball screw about a 1/16th of a turn before it engaged and moved the table. Now there's no play.

I did a quick adaptive test cut w a .25 2 for endmill at 5200rpm and 10% woc at 45ipm and it sounded so smooth. It's still a little too early to tell, but so far results are promising.

Any update on this? Is the squeal still gone. I'm going to be activating the mill again soon and I really need to eliminate the squealing problem I have.

[brianbonedoc]

Yeah - it definitely helped but believe it or not now it squeals when transiting from x to y moves like when I'm doing adaptive toolpath as soon as it turns the corner into a y move either y+ or y- it squeaks. Maybe gonna try to tighten up the y axis preload.

[SCzEngrgGroup]

Mine periodically develops a squealing noise due to lack of lubrication on the ballscrew free end bushings, or between the bushing block and the knob. A couple of times a year I remove the bushing blocks, grease them up, and put it back together.

Regards,
Ray L.

[brianbonedoc]

Thx Ray. Mine is definitely coming from the cutting tool. Dreading trying to tighten up the y axis preload. . .