Rockwell Automation 8520 9/Series CNC Lathe User Manual

Page 570

Compounding Turning Routines

Chapter 24

24-6

Figure 24.3

Parameters for G73 Roughing Routine

Shape after roughing

and final pass

Workpiece finished

shape

Start Point

(U+W)/2

(I+K)/2

In Figure 24.3, the contour blocks for this routine must define all motions

that would cut the workpiece finished shape. The first block of the contour

blocks must be the tool path from the start point to the point where the

initial roughing pass begins (point A to B in Figure 24.3).

The contour blocks can be programmed with or without a feedrate, or with

a G00 (rapid) command The control uses the feedrate specified by the

F-word in the G73 block during all roughing portions of the routine.

During the final contour pass of the roughing cycle, the control executes

your feedrate programmed in your contour block (unless you do not use

one, then it uses the F-word in the G73 block). This final contour can even

contain rapid moves (G00).

Important: The blocks preceding the G73 roughing block must have

positioned the cutting tool to a location above the part (start point in the

above figure) from which it can safely move to begin the roughing passes.

If cutting a Case 1 contour, the first of the contour blocks must command

X axis motion only (no Z axis motion). If cutting a Case 2 contour, the

first of the contour blocks must command both an X and Z axis motion.