[brooklynmetal]

I have had the head stock drop down a few times after I power down the machine.
If I turn off the Mach 3 contoller program, power down Windows
then shut down the machine, the head slides down until it hits the bed or the vise.
This screws up my Z location, therefore when I power back up I need to reset the Z home and re set my work offset.
Do I need to shut off the controller software?
Has anyone else had this problem? Any imput would be helpful.
Best, Dave

[TT350]

You gota titen up the gib on the Z

[redrider9112002]

I have the same problem, but its when I first power up the machine. However I resolve this by sending Z axis home, and then it stays. I'll cheek my gib. maybe thats it. Andrew

[TT350]

I think the weight of the head needs to be offset in some manner so the gibb doesn’t have to be so tight.

[rsmachine]

You have to adjust the Z axis gibb. There are instructions for this in the back of your users manual for the machine. It is a very simple process, but needs to be done after you have had the machine for a while. The issue is, once the machine "settles in" from use, it needs to be adjusted.

Sean

[TT350]

Ya I"ve read it.

[Khalid]

Install counterweight, if u still get problems..

[philbur]

Have I missed something here. When you turn of your machine/computer don't you lose the Z home/reference anyway. If you just shut off the machine you should not rely on the head maintaining position anyway. A few steps movement and you are screw. I think it's not good practice.

I think when you shut down and restart you should re-reference the home positions and the workpiece anyway.

Regards
Phil

I have had the head stock drop down a few times after I power down the machine.
If I turn off the Mach 3 contoller program, power down Windows
then shut down the machine, the head slides down until it hits the bed or the vise.
This screws up my Z location, therefore when I power back up I need to reset the Z home and re set my work offset.
Do I need to shut off the controller software?
Has anyone else had this problem? Any imput would be helpful.
Best, Dave

[brooklynmetal]

Phil,
I understand what you are saying, I'm used to manual milling with a two axis DRO (X,Y)
on a Bridgeport 2J and am getting aquainted with the CNC reality.
I think TT350 and Sean's referance to the Z gib adjustment makes sense.
It was unsettling to have the head slide down and not be able to stop it.
I will consult the manual on this issue.
Pleased to say I'm starting to get good results in the type of parts I'm making.
Thanks for the response.
Best,. Dave

[.xXACEXx.]

im sorry if this is off topic a lil' but ,i worked in a shop one time that had a milling machine that would drop the head whenever the power went off..i think that machine had to have a axis screw brake adjusted..i cant remember it was about 4 years ago...and i have the worst memory of all man kind...still the problem was really bad.one time a guy was simply indicating a hole on a part with a $200.00 interapid indicator when the power flickered...the head was on its way down slowly till it stopped ..with his indicator between the spindle and the part...needless to say the indicator was ...not god for anything any more... the machine also had that problem when you hit the emergency stop..so..you had better have a REALLY good reason to hit the stop button..you would sit there while the machine was throwing sparks.thinking to your self."i know i need to stop it,but i cant make my self do it...."cause it would most likely kill your part and tooling ...well thats my 2 cents

[rsmachine]

I had the same problem with my Tormach about a year ago, it sounds like they all do it. I just adjusted the gibbs and the head hasn't come down since. No need for counterweights, just adjust the gibbs and everything will be fine.

[nagjames]

My Machine is about 3 weeks old and had the same problem. After adjusting the gibbs my Z head no longer starts sinking after
starting up or powering off.
One thing I don't quite understand is the document states that when the power is off try to pull down
the head manually with 40-80lbs force well my whole wieght (140lbs) was not enough to pull the head down (while the power was off)
. But the head was still sinking down. So I adjusted the gibbs anyways at small increments like half turns and I stopped adjusting it when
it was not sinking anymore after startup.
Here is a video showing the sinking problem. After startup and shutdown.
http://nagycnc.com/temp/z_axis.wmv

Thanks,
James
http://nagycnc.com

[TT350]

My head fell for the first time the other day, it was
or first cool snap of the year about 50deg.

When it fell it didn’t obsolete like yours it just started
down in a smooth steady fall.

[300sniper]

are the heads still falling on the machines with the z axis brake?

[307startup]

I kinda thought that's what Greg said the Z-axis brakes were installed for, on the new machines...

[TT350]

I'm going to counter the weight of the head on mine.
I think titing the gibb to control this puts to much stress
and wear on the Z ball screws and ways.

All the big commercial machines are done this way.

[hawkman]

Might this be an unintended consequence of the Turcite surfaced ways that no reasonable amount of tightening would solve (low friction normally being a good thing).

[Khalid]

Before installing counterweight i will give u a few suggestion:
1) Contact the OEM
2)Low th IPM of the Z-axis i.e. By Tuning the Z-axis motor through the software
3) Installed the counterweight in such a way that it always lesser then the weight of ur z-axis movable gantry.

[Khalid]

Sorry omit the second suggestion:-)

[philbur]

I think this is the only real reason to worry about the Z-axis fall. The solution to this would appear to be a brake. If tightenng the gib (according to the manual) doen't get it then I would contact the OEM regarding a retrofit brake, or design one yourself.

The plus side of a falling Z is you know the gib is not to tight, causing unecessary wear.

Phil

.... the machine also had that problem when you hit the emergency stop..so..you had better have a REALLY good reason to hit the stop button..you would sit there while the machine was throwing sparks.thinking to your self."i know i need to stop it,but i cant make my self do it...."cause it would most likely kill your part and tooling ...well thats my 2 cents