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Fanuc 6T model B operations Guru help needed.

davidwenrich

Plastic
Joined
Oct 27, 2015
Hello everyone! I've recently purchased a Nakamura TMC2 (1981) 2 axis CNC lathe. It is equipped with Fanuc 6T Model B controller. I am having difficulty getting this machine up and ready for cycle start. Since acquisition, I have fixed the hydro-chuck drawtube malfunction (stuck), Successfully went from "not ready" display with no hydraulics at all (bad connections, dirty contactors) (lack of use) to a machine that powers up with no alarms (no NC alarm, no machine alarm) I can jog the spindle, I can open/close the chuck, I can index the turret, and I can run the spindle from the operators sub-panel. I CANNOT get the machine to zero-return!!! (home) I can't jog either axis. both spindle drives have the PRDY LED illuminated, both drives have correct voltages according to my understanding in the maintenance manuals. I have all documentation that cam with machine when purchased new. I have gone through several checks with parameter tables and DGN table, but they appear to be inaccurate for my machine. (known input allegedly found in parameter 0036 according to the manual, is actually changing state in parameter 0034 in the NC) several other discrepancies. What I don't know is, is my problem operator (self) error? or machine error? For instance, I was not aware that turret must be indexed, and chuck must be cycled, BEFORE the spindle will be started (MDI) Also I have not tried any programs, other than a simple spindle start line, because I assume nothing will execute due to no zero return. Any input for anyone familiar with 6T model B controls is appreciated. (Yes I read The manuals)
 

DouglasJRizzo

Titanium
Joined
Jun 7, 2011
Location
Ramsey, NJ.
When you say it won't zero return, what exactly, happens?
Does it move at all?
My experience with older machines is that if the turret or axis has been resting against a trip dog for a long period, then sometimes the trip dog will stick and the machine won't home properly.
 

angelw

Diamond
Joined
Sep 10, 2010
Location
Victoria Australia
I CANNOT get the machine to zero-return!!! (home) I can't jog either axis.
When you say you can't get the axes to Jog, are you referring to all movement of the Axes, in that no movement is possible via any manual mode, including Hand-wheel?

When in Hand-wheel Mode, does the position display change as you attempt to move either axes, but the physical position of the axes remains stationary? If so, its likely the the Machine Lock switch on the control panel is turned on. Ensure that its in the Off position and try the movement test again.

Regards,

Bill
 

davidwenrich

Plastic
Joined
Oct 27, 2015
When you say it won't zero return, what exactly, happens?
Does it move at all?
My experience with older machines is that if the turret or axis has been resting against a trip dog for a long period, then sometimes the trip dog will stick and the machine won't home properly.
No movement. Display will change (Absolute and Inc) Machine Pos. stays 0,0 Limit switches all seem to change state. (parameter screen) I can power up, and in this order successfully perform start up operations as follows:
1)Power on
2) Index turret (any tool I desire will function as intended)
3)unclamp, then clamp chuck, (Chuck closed indicator LED turns green)
4) Turn on main spindle to warm up (from jog panel)
5) Zero return is what will not function, and I believe it is next step, to ready machine for MDI.
No movement... no sound, no alarms, jog wheel and buttons both change the onscreen position. No program or command from MDI works.
 

davidwenrich

Plastic
Joined
Oct 27, 2015
When you say you can't get the axes to Jog, are you referring to all movement of the Axes, in that no movement is possible via any manual mode, including Hand-wheel?

When in Hand-wheel Mode, does the position display change as you attempt to move either axes, but the physical position of the axes remains stationary? If so, its likely the the Machine Lock switch on the control panel is turned on. Ensure that its in the Off position and try the movement test again.

Regards,

Bill
Machine Lock switch is off, tested change of state (24v) with multimeter.
No movement. Display will change (Absolute and Inc) Machine Pos. stays 0,0 Limit switches all seem to change state. (parameter screen) I can power up, and in this order successfully perform start up operations as follows:
1)Power on
2) Index turret (any tool I desire will function as intended)
3)unclamp, then clamp chuck, (Chuck closed indicator LED turns green)
4) Turn on main spindle to warm up (from jog panel)
5) Zero return is what will not function, and I believe it is next step, to ready machine for MDI.
No movement... no sound, no alarms, jog wheel and buttons both change the onscreen position. No program or command from MDI works.
 

angelw

Diamond
Joined
Sep 10, 2010
Location
Victoria Australia
No movement. Display will change (Absolute and Inc)
So what does that mean exactly? Are you saying that there is no actual movement of the axes, but that the numbers displayed in the Absolute and Incremental Display Screen are changing when you attempt to move the axes by either Jog or Hand-wheel? If so, Machine Lock is ON, notwithstanding that the your test of the switch is indicating that its OFF.

If you're testing right at the switch, that will test if the switch is operational, but its possible for the circuit to be shorted elsewhere so that Machine Lock is on irrespective of the switch position. You would have to look at the Inputs to the Control via Parameter/Diagnostics to confirm if Machine Lock is ON or NOT.

The other alternative for the Position Readout to change, but have no physical movement of the axes is that the power supply of the axes' drives are faulty.

Regards,

Bill
 
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davidwenrich

Plastic
Joined
Oct 27, 2015
So what does that mean exactly? Are you saying that there is no actual movement of the axes, but that the numbers displayed in the Absolute and Incremental Display Screen are changing when you attempt to move the axes by either Jog or Hand-wheel? If so, Machine Lock is ON, notwithstanding that the your test of the switch is indicating that its OFF.

If you're testing right at the switch, that will test if the switch is operational, but its possible for the circuit to be shorted elsewhere so that Machine Lock is on irrespective of the switch position. You would have to look at the Inputs to the Control via Parameter/Diagnostics to confirm if Machine Lock is ON or NOT.

The other alternative for the Position Readout to change, but have no physical movement of the axes is that the power supply of the axes' drives are faulty.

Regards,

Bill
 

davidwenrich

Plastic
Joined
Oct 27, 2015
dParameter 0100 Bit 1, and parameter 34, bit 1 (both) change state when switching machine lock on/off. When machine powered off, ballscrews can be turned by hand. (axis can be manipulated)
When machine powered on, turret indexed, spindle started/stopped, servo has control of screw (cannot move, can feel the brake of the servo holding (buzz, vibration when trying to force)
This tells me servo has power, and servo drive is waiting to be told what do, but has not been "told" what to do.
 

davidwenrich

Plastic
Joined
Oct 27, 2015
And yes on the position screen page that shows ABS/INC/Machine position, the ABS and INC move, but the machine does not.
 

atex57

Hot Rolled
Joined
Sep 6, 2006
Location
SW Wisconsin
On my 6T and 3T machines the first thing I do is jog the axis's away from the switches then do the homing.

What is the exact procedure you are using, switch by switch and button by button?
Some machines are very specific on order of use.

Ed.
 

davidwenrich

Plastic
Joined
Oct 27, 2015
No movement. Display will change (Absolute and Inc) Machine Pos. stays 0,0 Limit switches all seem to change state. (parameter screen) I can power up, and in this order successfully perform start up operations as follows:
1)Power on
2) Index turret (any tool I desire will function as intended)
3)unclamp, then clamp chuck, (Chuck closed indicator LED turns green)
4) Turn on main spindle to warm up (from jog panel)
5) Zero return is what will not function, and I believe it is next step, to ready machine for MDI.
No movement... no sound, no alarms, jog wheel and buttons both change the onscreen position. No program or command from MDI works.

Reply
 

atex57

Hot Rolled
Joined
Sep 6, 2006
Location
SW Wisconsin
No movement... no sound, no alarms, jog wheel and buttons both change the onscreen position. No program or command from MDI works.
Are you saying the jog wheel and buttons change the onscreen position but not moving the axis or is it moving as you turn the jog wheel?

Are you following the EXACT procedure to home the machine? Mine home the X and Z first then the spindle, gears, etc. Order counts.

Ed.
 

Vancbiker

Diamond
Joined
Jan 5, 2014
Location
Vancouver, WA. USA
I suspect the axis interlock signal is on, feedhold is active, or start lock signal is on. If I get a chance to look up the addresses tomorrow I’ll post them.

Another thought, does this machine have or did have a tool touch off device. If so, a broken wire to that or if disconnected will cause axes to not be able to move in any mode.
 
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