Rockwell Automation 8520 9/Series CNC Lathe User Manual

Page 595

Compound Turning Routines

Chapter 24

24-31

Figure 24.24

Pattern Repeating Routine Parameters

Cutting feed

Rapid feed

(start point)

Shape defined by

workpiece contour blocks

Finishing pass

(I+K)/2

(U+W)/2

Note: Tool paths not to scale.

In Figure 24.24, the contour blocks for this routine must define all motions

that would cut the workpiece finished shape and the tool path that connects

the start point of the routine to the first block of the workpiece finished

shape. The first block of the contour blocks must be the tool path from the

start point to the first block of the workpiece finished shape. It is assumed

that some other blocks have positioned the cutting tool to a position above

the part (start point in the above figure).

The arc and pocket in the example above get smaller and smaller as the

passes get farther away from the final contour. If you specify passes very

far from the final contour, the cutting tool can be too large to cut the

resulting arc or pocket. When this occurs the control generates the error

message “INVALID CYCLE PROFILE”. Resolve this problem by making

the distance from the final pass to the first pass smaller. This cycle was not

designed to remove large amounts of material. Its intended design is to

perform cleanup passes on castings or forgings. If you must remove large

amounts of material you should use one of the roughing/facing routines

discussed earlier in this chapter.