Siemens SINUMERIK 840DE Programming Manual page 146

Programming Motion Commands
4.13 Involute interpolation (INVCW, INVCCW)
Note
For more information about machine data and supplementary conditions that are relevant to
involute interpolation, please see References: /FB1/, A2 section "Settings for involute
interpolation".
Example of counterclockwise involute and back as clockwise involute
Counterclockwise involute according to programming method 1 from start to end point and
back again (clockwise involute)
N10 G1 X10 Y0 F5000
N15 G17
N20 INVCCW X32.77 Y32.77 CR=5 I-10 J0
N30 INVCW X10 Y0 CR=5 I-32.77 J-32.77
...
4-40
;Approach start position
;Select X/Y plane
;E. counterclockwise, end point,
;radius, center point relative to
;start point
;Start point is end point from N20
;End point is start point from N20,
;radius, center point relative to new
;start point is equal to previous
;center point
Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
Fundamentals