[huggybaird]

First time poster here that wanted to share a problem to help others. I've contacted tormach support and hopefully they solve it. I'll post the resolution once I get it. Or, feel free to comment if you've ever seen this before.

Details of problem:
Any X+ or X- axis milling sounds terrible. As soon as the machine switches to the Y- or Y+ movement the sound goes away. video here

https://www.youtube.com/watch?v=_Jzf4R2tSIg

The video is a block of 6061 aluminum being milled by a 1/2 4 flute HSS end mill. It's at 3600 RPM, 30 IPM, .3 DOC, .1 stepover.

The video is just an example, this problem remains across the following tests:
1. tried a 3/8 or 1/4 end mill
2. lowered/raised RPM
3. lowered/raised IPM
4. changed stock to 1018 steel
5. choked up tool in collet for less stickout
6. 2 vs 4 flute, HSS vs carbide

none of the above make any difference. the only way i can get X to not sequel is to do something ridiculously slow like a .03 DOC on a 3/8 end mill.

[jwatte]

Sounds like something loose is causing backlash/chatter when going that direction.
Possibly the gibs or the ballnut. But could be anything. (Could be workholding, even :-)

[huggybaird]

Thanks jwatte. I am a bit of a noob, but I suspect you are right. Just not sure how to isolate what is loose

Hopefully tormach support gives some suggestions. I'll post any info I get here to help the next guy

[R.DesJardin]

Speeds and feeds and cutter, that is just the Tormach harmonic death squeal. Looks like you are cutting a radius at each end, more cutter engagement which can cause the vibration howl. Lots of ways to eliminate that, less DOC, less WOC, dont't limb cut, more rpm with one of the previous in aluminum, smaller cutter, I'd use a 1/4" rougher, leaving .01" on the sides and finish with a 1/4", finishing with conventional cutting direction can help too. Just judging from how big pocket looks. Seems I read the corner radius needs to be 3 times cutter radius to reduce corner vibration. What holder are you using, it looks really long.

[jwatte]

In my experience, to reduce chatter, you want to reduce the RPM and/or increase the feed rate. Less load on the cutter just gives it more chance to vibrate, rather than being held by cutting forces. (There is of course the death limit where you take a bigger bite than the cutter or chip clearing can deal with, and you clog and break. Don't go that far!)

[huggybaird]

Hi all,

As an update, Jenny from tormach support did respond within 48 hours and it is the holiday season. Unfortunately, it did not work for me, but I wanted to share the solution because I expect it will work for others.

After reflecting on this, I think I let the noise run too long and the spindle may have worn due to the chatter. A wiser person would have fixed the issue immediately with the solution below. I'm going to try replacing the spindle and will report back. But for most people i expect this will be helpful:

"
regarding your squawking X axis - and I was able to take a look at your video. I think we may have an idea of what may be going on, and I am emailing you with something to try out. We had a similar issue with one of our shop mills, and this seemed to take care of the issue.

It may not be chatter coming from the axial motion, but from the spindle bearing preload loosening itself up.

You will need a spanner wrench that fits on the spindle preload nut.

You may need to move the spindle pulleys to get to it. There are 3 set screws on the spindle preload nut. Back these setscrews out, smack the preload nut down with a deadblow. Then tighten down the nut with a spanner 20-30 ft lbs., and tighten up the set screws again, this may alleviate the chatter. I placed a photo below, pointing out the notches for the spanner.


I realize that this sounds kind of odd – but we are finding that the loosening of the preload on the spindle causes squawking – just like you exhibited in your video. And oddly enough, it always seems to manifest in the X axis. We are doing more work on this, but give it a shot and let me know if this helps!
"

image attached

[huggybaird]

********SOLUTION*******
********PROBLEM SOLVED**********

I wanted to share the solution in hopes it benefits other PCNC 1100 users that have excessive X axis chatter/vibration.

Solution:
Z-axis gib adjustment - DO NOT follow the tormach user's manual to adjust the Z axis gib. Tormach is changing the manual according to the support technician that helped me. They will publish a new manual later this year

To adjust the Z axis gib:
1. Remove the way cover
2. Lube the ways with a chipping brush (optional step) to ensure maximum lubricity
3. Tighten the gib
4. Run the machine for 10 minutes to wear in the gib/ways
5. Set a dial indicator as close to the table as possible and check for lost motion targeting < .0025 (.0016 on newer machines). Run it all the way up/down 10 times (not just once)
6. Repeat steps 3 through 5

Two months ago, I followed the tormach user manual and tightened the gib. But the manual leaves out step 4. Thanks to their technical support, I tried again with the steps above. I tightened the gib about 15 full rotations on the screw moving it 3/4 of an inch. Now, it sounds like a brand new mill.



Jenny from Tormach support is awesome and my hero. We tried several different things (spindle preload, drawbar/collet adjustment, etc). Each one she sent me pictures with arrows to walk me through the process. Even though I was out of warranty, she even sent me some complimentary parts. Highly recommend you ask for her if you ever open a ticket.

Hats off to Jenny from Tormach Support

[Steve Seebold]

First time poster here that wanted to share a problem to help others. I've contacted tormach support and hopefully they solve it. I'll post the resolution once I get it. Or, feel free to comment if you've ever seen this before.

Details of problem:
Any X+ or X- axis milling sounds terrible. As soon as the machine switches to the Y- or Y+ movement the sound goes away. video here

https://www.youtube.com/watch?v=_Jzf4R2tSIg

The video is a block of 6061 aluminum being milled by a 1/2 4 flute HSS end mill. It's at 3600 RPM, 30 IPM, .3 DOC, .1 stepover.

The video is just an example, this problem remains across the following tests:
1. tried a 3/8 or 1/4 end mill
2. lowered/raised RPM
3. lowered/raised IPM
4. changed stock to 1018 steel
5. choked up tool in collet for less stickout
6. 2 vs 4 flute, HSS vs carbide

none of the above make any difference. the only way i can get X to not sequel is to do something ridiculously slow like a .03 DOC on a 3/8 end mill.

That sounds to me like your high speed steel end mill is chattering. Maybe you have too much cutter sticking out of the spindle/holder.

[upnorth]

I find this to be interesting. This problem is not limited to a Tormach mill. I have a novakon mill that sounds exactly like your video. No matter what I tried with speeds and feeds it squeals like yours. The effect is particularly bad when cutting steel. It would trash a brand new end mill in an hour or so. Little chips missing from the end mill. Thanks for taking the time to post your solution. I'm going to give it a try when I take my mill out of winter storage.

[a_j_p]

So I realize this is a few years later... But ultimately this solved an issue for me so I figured I'd reply.

I have a 2 year old 1100M that would squeal when travelling in the X direction but ONLY with >= 1/2" tool and ONLY when taking a finishing pass (most often with a 1/2", 3 flute, higher helix tool and a deeper cut, i.e. >20mm DOC). I could take roughing passes at the same DOC (bigger stopover, lower RPM to better match the spindle power) and it would sound fine, but coming back to finish it up and it would squeal in the X direction.

In the past when this started happening (maybe every 6-8 months it would start), putting in a fresh Lyndex R8 collect and new Belleville washers seemed to resolve it. But recently this did not work for me. I went through all of the axes checking gibs, angular contact bearings, ballnuts and connecting bolts, but when finished the problem persisted (I did however find loose bolts on the Y axis angular contact bearing housing so it was still worth checking).

Finally I tried huggybairds suggestion from Tormach above regarding smacking the spindle preload nut with a deadblow and re-tightening. Voila sounds like a new machine.

It's not super easy to do this but it's really not too difficult either. You either have to pull the spindle out or remove the spindle motor. I opted to pull the motor and power drawbar and it took maybe 2 hours, including cleaning out all the random chips/grease that worked their way into the head.