Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 578)

Compounding Turning Routines
Chapter 24
24-14
7. A rough cut is made at feedrate F, into the workpiece parallel to the X
axis to the X coordinate of the last rough cut.
Steps 2 - 7 continue to repeat until the operation is aborted or the rough
contour shape is completed. The rough contour shape is completed when
the thickness of the remaining material to be removed from the contour is
equal to the sum of the finish allowance (U+W)/2 and the final pass
allowance (I+K)/2. If no final pass is to be cut, skip to step 9.
If a final pass is programmed in the G73 block (I or K values in the G73
block) it is not executed until all of the workpiece pockets have been
completely roughed out.
8. The final pass is made at the feedrate programmed in your contour
block including rapid moves (if no feedrate is programmed in the
contour blocks, the control uses the F-word in the G73 block). Only
the amount of material specified with the final pass allowance
(I+K)/2 is cut. This cut is made parallel to the exact contour of the
final workpiece, it is not a roughing pass. After this cut is complete,
the only remaining material on the workpiece contour is the finish
amount (if any) as programmed with U and W.
9. The control returns the cutting tool, at a rapid feedrate, to the start
point of the cycle.
Example 24.3
Case 2 G73 Roughing Routine
N010 G00X100.Z150.;
N011 G73P13Q20U.8W.8I.6K.6D10.R7.F100.;
N012 M30;
N013 X85.Z135.;
N014 X15.Z115.;
N015 Z82.;
N016 X45.Z72.;
N017 Z55.;
N018 X35.Z50.;
N019 Z22.;
N020 X80.Z7.;