How to set up center of rotation on Horizontal Mill

[tsaladyga]

Hi guys,
I am in need of some help this morning. We have several okuma horizontal MA600-HB machines and the old programmer didn't know how to program from center of rotation. So his programs are done with a lot of formulas to figure out Z at different rotations. I would like to start programming from center of rotation so that I don't have to figure that stuff out.
Does anyone know of a way to set up the machine so I can set my fixture offsets from center of Rotation?
Thank you,
Todd Saladyga

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[skywalker4]

find how far it is from the spindle to the center of your pallet(should be on the machine or the book. and measure you tools overall length minus the gap that exists between the holder and spindle face when the tool is in the spindle. use that for you tlo.

[deadlykitten]

hi something seems out of place : such good equipments without programming skills / if i may, what happened ?

ma600-hb = [ vmc + 4th axis + turn_cut_option ] + 90* rotation
... or
ma600-hb = live tools lathe + indexing chuck

kindly

[skywalker4]

deadly kitten is the okuma man. kindly

[deadlykitten]

hello again, let's try to make things work : share a photo with your fixture, describe the existing approach, and what you don't like about it, and how you wish to change it pls be specific just a bit


i am sorry, i can't understand exactly what you wish for :
... do you rotate the 4th axis, and you wish to reposition? to much math involved ?
... all programs have Z0 in the center of the 4th axis, or Z origin is relative to table center ?
... tombstones ? complex fixture ?

kindly



ps : hi skywalker

[tsaladyga]

find how far it is from the spindle to the center of your pallet(should be on the machine or the book. and measure you tools overall length minus the gap that exists between the holder and spindle face when the tool is in the spindle. use that for you tlo.

I was able to figure it out guys. I found center of table like Skywalker4 suggested, created offset H10 for center of rotation and called the other offsets from that point.
So basically we are running two parts per tombstone and this is how I was able to achieve it.

OSET1
(**** FIXTURE ZERO ****)
(*******SETS CENTER OF ROTATION*****)
VZOFX[10]=0.0
VZOFY[10]=0.0
VZOFZ[10]=-12.509
VZOFB[10]=0
RTS



OSET2
VC110=1(SETS ACTIVE PALLET)
(*******PART ZERO**********)
(*** B0 COORDINATES *** )
VZOFX[20]=VZOFX[10]+7.000
VZOFY[20]=VZOFY[10]+14.57
VZOFZ[20]=VZOFZ[10]+5.26
VZOFB[20]=0

VZOFX[30]=VZOFX[10]-7.000
VZOFY[30]=VZOFY[10]+14.57
VZOFZ[30]=VZOFZ[10]+5.26
VZOFB[20]=0
RTS

OSET3
VC110=1(SETS ACTIVE PALLET)
(*** B180 COORDINATES *** )
VZOFX[40]=VZOFX[10]-7.000
VZOFY[40]=VZOFY[10]+14.57
VZOFZ[40]=VZOFZ[10]-4.19
VZOFB[40]=180

VZOFX[50]=VZOFX[10]+7.000
VZOFY[50]=VZOFY[10]+14.57
VZOFZ[50]=VZOFZ[10]-4.19
VZOFB[50]=180
RTS

[deadlykitten]

hello tsaladyga, there are different ways to put the origin

using a system variable is ok, especially if you declare the origin without being near the cnc

instead of :

OSET2
VC110=1(SETS ACTIVE PALLET)
(*******PART ZERO**********)
(*** B0 COORDINATES *** )
VZOFX[20]=VZOFX[10]+7.000
VZOFY[20]=VZOFY[10]+14.57
VZOFZ[20]=VZOFZ[10]+5.26
VZOFB[20]=0

VZOFX[30]=VZOFX[10]-7.000
VZOFY[30]=VZOFY[10]+14.57
VZOFZ[30]=VZOFZ[10]+5.26
VZOFB[20]=0
RTS

you may use this shorter code:

 
    NOEX VC110 = 1
 
    G15 H10
 
    G11 X+7 Y+14.57 Z+5.26 ( coordinate system conversion )
    // cutting with actual corections
    G10
 
    G11 X-7 Y+14.57 Z+5.26 ( coordinate system conversion )
    // cutting with actual corections
    G10
 

however, even so, it is too much code; also this is possible :

O****
  
    NOEX VC110 = 1 ( active pallet )

    NOEX VZOFX [ 30 ] = +7 VZOFY [ 20 ] = +14.57 VZOFZ [ 20 ] = +5.26 VZOFB [ 20 ] = 0
    NOEX VZOFX [ 30 ] = -7 VZOFY [ 30 ] = +14.57 VZOFZ [ 30 ] = +5.26 VZOFB [ 30 ] = 0
 
RTS

this last sample requires a determined cnc, thus the origin at the middle of the table is no longer declared inside G15H10, but as the origin of the abso-encoders

and the code can be futher enhanced, so to reduce future edit time :

O****
  
    NOEX VC110 = 1 ( active pallet )

    NOEX VZOFX [ 20 ] = +7 VZOFY [ 20 ] = +14.57 VZOFZ [ 20 ] = +5.26 VZOFB [ 20 ] = 0
    CALL OCOPY LV01 = 20 LV02 = 30
    NOEX VZOFX [ 30 ] = - VZOFX [ 30 ]
 
RTS

OCOPY ( copy work coordinate system; LV01 : source , LV02 : target )
 
    NOEX VZOFX [ LV02 ] = VZOFX [ LV01 ]
    NOEX VZOFY [ LV02 ] = VZOFY [ LV01 ]
    NOEX VZOFZ [ LV02 ] = VZOFZ [ LV01 ]
    NOEX VZOFB [ LV02 ] = VZOFB [ LV01 ]
 
RTS

kindly

[deadlykitten]

code from this post is equivalent with code from post #6

requirements : ocopy soubroutine + shifting the abso-encoder origins ( grid shifting )

* if you have allready some soubroutine, just add 1 more
* shifting the encoder origin comes with some advantages :
... origins will no longer be floating, but relative to an absolute position ( real palpable position )
... tool offsets and fixture coordinates may be declared by using measuring instruments ( calipers, indicators, etc ) with a precision < 0.1
... alows checking how much the cnc components have moved overtime ( a heavy table may tilt, maybe will move down, towards the foundation )
... alows declaring the origins without being near the cnc
... sync the machine with the cam and with the external tool measuring unit
*etc

kindly

 
    NOEX VC110 = 1 ( active pallet )
 
    NOEX VZOFX [ 20 ] = +7 VZOFY [ 20 ] = +14.57 VZOFZ [ 20 ] = +5.26 VZOFB [ 20 ] =   0
    CALL OCOPY LV01 = 20 LV02 = 30
    NOEX VZOFX [ 30 ] = - VZOFX [ 30 ]
 
    NOEX VZOFX [ 40 ] = -7 VZOFY [ 40 ] = +14.57 VZOFZ [ 40 ] = -4.19 VZOFB [ 40 ] = 180
    CALL OCOPY LV01 = 40 LV02 = 50
    NOEX VZOFX [ 50 ] = - VZOFX [ 50 ]