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Use Tailstock On Mazak QT Nexus 200 With No Thrust Applied To Work Piece

David_M

Hot Rolled
Joined
Sep 30, 2014
Location
Midway, GA, USA
It is a Japanese made QTN 200 model from the early 2000's. I did not get the EIA/ISO option.

I would like to machine some delicate Teflon parts that have a central 3mm hole. I plan to use a hardened and polished rod as a dead center in the hole's entrance. It's important that the tailstock not apply any thrust, though.

Is it possible to set the tailstock to work this way with code or with a changed parameter?


Edit: I wonder if I could use 'Set Home Position' to help out some way?

Thanks!

David_M
 
Last edited:
Under the MAINT page soft key options you should see one for TAIL or TAIL THRUST ( can't recall right now ) Once, in there, you will see 5 or six options for thrust pressure. Use the lightest one, on the left. All the set point function does is tell the machine to throw an hissy fit ( alarm ) if the center travels past that point by a certain amount.
 
Under the MAINT page soft key options you should see one for TAIL or TAIL THRUST ( can't recall right now ) Once, in there, you will see 5 or six options for thrust pressure. Use the lightest one, on the left. All the set point function does is tell the machine to throw an hissy fit ( alarm ) if the center travels past that point by a certain amount.

Hey Zahnrad,

The lowest is 1kn (225 pounds) :(. I'm working with Teflon that is .5" diameter and the thrust crushes it.

What I'm thinking about is to give the tailstock a new home position that is much closer to the chuck. Then use a 1/2" MT5 end mill holder in the tailstock with an ER11 straight shank collet chuck gripping a 3mm dowel pin (this slides freely in the end mill holder for room to change parts). After putting the Teflon part loosely in pie jaws, I would slide the collet chuck's dowel pin into the 3mm drilled hole of the part, then lock it in its new position in the end mill holder (if any of this makes sense).

Best regards,

David
 
I found a solution.

In a nutshell I changed R-97 (R-97 sets the value for the far left tailstock pressure selection) to a value of 1. That makes it give the confirm beep without the tailstock moving.

Using an MNP unit:

732 to set pressure to second value
742 move to second tail position. this is where it needs to be to support fragile part on the pin.
731 set tail pressure to the first selection
741 move tail to position 1 (position 1 is set 1" closer to chuck than position 2). tail won't move because of R-97 setting, but you get the conformation beep and program runs without error message.
732 set to second pressure value (if you use the arrow keys to move the tailstock manually it will move as expected)



Tailstock has to be sent to its home position before you can run this again.
MNP
M05
M09
M32
 
Nice. Good work!
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Just a follow up.

The job went well with changes:

Using an MNP unit:

M05 //Stop Spindle
M09 //Stop Coolant
732 //Set to a value other than 731
742 //Move to second tailstock position. This is where it needs to be to support fragile part on the pin.
731 //Set tailstock pressure to the first selection (This is the one that has been changed to 0 for parameter R-97)
741 //Move tailstock to position 1 (Position 1 is set .040" farther from the chuck than position 2 (A less negative number)). Tailstock won't move because of R-97 setting, but you get the conformation beep and program runs without error message.
732 //Set to a value other than 731 (If you use the arrow keys to move the tailstock manually, it will move as expected)
 
Hi,
We are trying to do the exact same thing on a QT250 Smooth G machine. We tried changing RB74 Bit3 to 1 with no effect. Basically we have a manual program to M741. However the machine alarms to 170 W axis thrust force alarm. RB31 Bit 1 has also been changed to 1. We cannot have any pressure as the part is thin Teflon.
 








 
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