Loud at 12K RPM - 05 VF3ss

[ccjung]

Hey Guys

I've been loving my 05 VF3SS and have become way more productive since moving from my little Tormach to this Haas.

I have been able to hammer away a months work in little over a week and am loving the machine. One thing we have noticed though, is that at 12000 RPM its pretty loud.

Recently, ive heard a more distinctive rattling like sound when running at top speed. I've eliminated workpiece stability as a factor, since it makes the noise at no load.

I'm also not sure if its just a normal sound, or harmonics. Any advice would be appreciated.

Chris

[Geof]

If you twist the spindle back and forth quickly by hand to you hear any clunking or rattling? One source of a high speed rattle is a loose pulley for the encoder drive. Also if your drive belt has lost a tooth or two it can make a lot of noise.

You might be faced with taking the cover off and running it open to see if you can locate the source.

[ccjung]

I'll have a looksee in a second when we are done with this cycle.

One thing i have noticed is that i will never see an actual speed of 12000, always 11996 or so.

Dont know if it makes any difference, but im assuming if a belt has lost a tooth or two the rotary encoder would be off, causing the motor to want to speed up/down?

[Matt@RFR]

Originally Posted by ccjung One thing i have noticed is that i will never see an actual speed of 12000, always 11996 or so.

My '07 VF-2ss has been exactly like that from day 1. So far it hasn't impacted anything, not even rigid tapping down to 2-56.

Are you warming up your spindle before running it at high RPM? Have you had any crashes lately?

[Geof]

Originally Posted by ccjung .....Dont know if it makes any difference, but im assuming if a belt has lost a tooth or two the rotary encoder would be off, causing the motor to want to speed up/down?

A few lost teeth do not make any difference, there are more than twenty teeth engaged on the pulley all the time so you you have to strip a lot off in a crash to get drive problems. (But then you have lots of other problems.)

I wouldn'y worry about the speed deing 11996, that is accurate to 4 parts in 12,000.

[ccjung]

I run the spindle warm up every morning before cutting and run the spindle at S1000 for 10 minutes as I prepare to call it quits for the day. My machine is set to Auto Off at 20 minutes so the spindle fan can stay on for at least that long after a long day.

I dont think its impacting anything. If i had to best explain the sound, it sounds like a rattling fan at high speed. Not sure if its not even just flourescent lamp fixture above the machine thats rattling. I'm not a machinist, but as an engineer, the ear is a pretty good tool.

I havent had any major crashes. Just one where a 4-40 tap got programmed incorrectly and a small 3/16 EM snap.

The other thing i have installed on this system is the auxiliary coolant filter. It adds a slight lag to on/off functions of the coolant, and may be a snag in the coolant for the spindle?

And as every owner has, i have the chip accumulation issue on my drainplate.

[Geof]

Originally Posted by ccjung .... Not sure if its not even just flourescent lamp fixture above the machine thats rattling...

I had one similar to that. It only occurred when the machine was taking a heavy cut in one direction, drove me crazy until I tracked it down.

[Pondo]

At 12K an off balance toolholder will make a ton of noise. We had a guy that would put in set screw holders and run them at 10-12K. Made a ton of noise and I'm sure it was bad for the machine.
I personally run set screw holders no faster than 5K, collet holders up to 12K, and above 12K I run shrink fit holders. Good collet holders should be OK to 15-20K, but no need when there are lots of shrink fit holders in our shop.
I'm not saying that's the problem for you, but if you notice it's a different sound with different holders it might be.

[Matt@RFR]

Originally Posted by Pondo I personally run set screw holders no faster than 5K

What brand? I run Mari Tool endmill holders at 12k all the time and they have never made any wierd noises, nor can you feel anything through the sheetmetal or on the spindle.

[ntcnc]

Anything over 10k needs to be balanced tool holders no matter what style.

[ccjung]

I run er16 collet style holders. they are g2.5 balanced. in my reading I see that the vibration sensor can be turned on. anyone know how?

[Pondo]

Originally Posted by Matt@RFR What brand? I run Mari Tool endmill holders at 12k all the time and they have never made any wierd noises, nor can you feel anything through the sheetmetal or on the spindle.

I've had them vibrate pretty bad at 7500 RPM even. All different brands - Command to Haas to Fitz-Rite. They are inherently unbalanced. The tool has a flat ground in it that varies, the setscrew varies it's radial distance depending on the flat, and the slip fit of the holder to the tool means that it is always a couple tenths off center to begin with. Check it with an indicator.
It gets worse as the tool dia gets bigger as well.
If it works for your application, then that's great. I'm just trying to make people aware that it may be an issue, and in my experience it may go overlooked. I'd suggest next time that job is running, try a collet holder instead of a set screw holder once and see if there is a difference in the sound. Maybe it doesn't sound weird because it's become a "normal" sound. By the time it starts shaking the machine it is really vibrating a ton.