Rockwell Automation 8520 9/Series CNC Lathe User Manual
Page 596
Compounding Turning Routines
Chapter 24
24-32
Prevent this invalid cycle profile error by keeping the right portion of the
following equation less than the radius of any arcs in your cycle profile.
R
²
p
(I+U)
2
+ (K+W)
2
+
(tool radius)
The same basic equation can apply to other contours. If the length of a
block in the contour is less than the right portion of the above equation,
you can get an “INVALID CYCLE PROFILE” error depending on your
part contour. For contours with pockets, the width of the pocket must be at
least twice the value of the right hand portion of the above equation. In
general this error is a result of removing metal too far from the original
part profile (I, K, U, or W too large) and reducing this distance typically
resolves the error condition.
The workpiece contour blocks can be at any location within the same
program containing the G75 block (even after an end of program block).
They can not be resident in a subprogram or macro that is called by the
program containing the G75 block. Contour blocks can be either circular
or linear blocks. Any F-, S-, or T-words that are programmed in this set of
contour blocks are ignored when they are executed as workpiece contour
blocks in the G75 mode.
In Example 24.7, the workpiece contour blocks are blocks N11 - N14.
Example 24.7
Typical G75 Block Followed By Blocks Defining Final Contour
N005 G75P11Q14I2.W2.D3.F10.S210;
.
.
.
N010 M30.;
N011 X24.;
N012 X55.Z40.;
N013 X65.Z35.;
N014 X70.Z5.;
The control generates multiple passes each offset from the other by an
amount equal to the total material to be removed (I+K/2) divided by the
number of passes (D) minus 1. The tool paths repeat until (D) tool paths
have been made across the part. Each tool path is shifted sequentially by
the distance obtained in this division to generate roughing paths. If a
finishing allowance (U, W) was programmed in the block, it is left uncut.
After the completion of the roughing routine, the cutting tool returns to the
routines starting point.