Rockwell Automation 8520 9/Series CNC Lathe - Manual (Page 568)

Compounding Turning Routines
Chapter 24
24-4
Figure 24.2
Workpiece Finish Contour Case 1 and Case 2 (G73)
X
Start Point
Z
X
Start Point
Z
Case 1 Case 2
The G73 block is programmed with this format:
G73P__Q__U__W__I__K__D__R__F__S__T__;
Where : Is :
P__
the sequence number (N-word) of the first block in the set of contour blocks that
define the final contour.
Q__ the sequence number (N-word) of the last block in the set of contour blocks that
define the final contour.
U W determine the finishing allowance that is left on the part when the routine is
completed. This finish allowance is typically removed later in the program when a
G72 finishing routine block is executed. The actual value of the finish allowance is
equal to the average of the U and W parameters (U+W)/2. It is not necessary to
enter both of these parameters in the calling block. If only one is entered, the control
uses half of the entered parameter value as the finish amount. The finish allowance
is optional and does not need to be programmed. See Figure 24.3 to determine the
sign of U and W. U and W are always programmed as incremental values.
Important: This manual makes the assumption that U and W are assigned in
AMP as the incremental axis names that correspond to the X and Z axes
respectively.
Important: The value assigned to U is affected by radius/diameter mode
(G08/G09). W is not affected by radius diameter mode. If programming in diameter
mode the value of the finish allowance is really ((U/2)+W)/2.