Why does the machine make a whinning sound and the Z load is always changing between 50 percent and 80 percent with the machine just sitting?

Is the rpm steady, or is it accelerating/decelerating? Anything running hot?

Why does the machine make a whinning sound and the Z load is always changing between 50 percent and 80 percent with the machine just sitting?

It sounds like your Z servo is oscillating. I had a situation like this on a Super MiniMill a few years ago.

The whining would go away if you jogged the axis but as soon as you stopped it would gradually start again.

It was possible to make the whine change its tone by pulling or pushing on the axis and if I took a rubber hammer and gave it a bang the whine would go away.

It was a new machine under warranty and the technician came in and played with the parameters and everything settled down and has been fine since.

If yours is an old machine that has just started doing this it is possible you are faced with your servo amp going toes up.

However, if it is an old machine with the high pressure nitrogen counterbalance maybe the pressure has dropped changing the static load on the servo and you may fix it by taking the pressure up to what it should be.

Its been like that from new rpm seems fine everything works good are vf-5 is only at 6 percent and doesnt make that annoying noise but it isnt a high speed machine. Just wondering why I guess.

The machine is 3 years old

The machine is 3 years old

Okay that means it does not have a counterbalance. The weight of the head is just carried on the Z axis servo. The Z load should be somewhere around 50 or 60% and it should be constant and there should not be any whine. Did you try pushing it up.

Get some blocks of wood, put one on the table and use another piece like a pry bar to push up the on the spindle nose. All you want to do is put a couple of hundred pounds force upward to carry some of the weight.

If it is the servo oscillating as soon as you take away some of the weight it is carrying the noise will change. You will also see the Z load change, it will go down as you lift the head.

My old TM-1 didn't have a counterbalancer and the load on the z was always on the high side just sitting there.

My Okuma is the same way, no counterbalance, high load in z just sitting. I usually hit the e-stop when I'm not going to use the machine for a little while.

I've never had the whining from either machine though. I'd definitly have the tech check it out.

There is a parameter for the z-axis .. low pass 1x,2x,4x,8x...... I believe 2x is set to 1 .. change 2x to 0 and 1x to 1 see if it makes a difference .... if the last does not fix it do the same for the 4x and 8x .. cannot have both at 1

ok I will try it

Ok so it ended up being parameter #29 i changed dfilterx8 to 0 and dfilterx4 to 1 and the humming noise is gone and the load meter stays on 60.