HEIDENHAIN iTNC 530 User Manual page 234

Programming a helix
Always enter the same algebraic sign for the direction of
rotation and the incremental total angle G91 H. The tool
may otherwise move in a wrong path and damage the
contour.
For the total angle G91 H you can enter a value of
-99 999.9999° to +99 999.9999°.
U Polar coordinates angle: Enter the total angle of
12
tool traverse along the helix in incremental
dimensions. After entering the angle, specify the
tool axis with an axis selection key.
U Coordinate: Enter the coordinate for the height of the
helix in incremental dimensions.
U Enter the radius compensation according to the table
above.
Example NC blocks: Thread M6 x 1 mm with 4 revolutions
N120 I+40 J+25 *
N130 G01 Z+0 F100 M3 *
N140 G11 G41 R+3 H+270 *
N150 G12 G91 H-1440 Z+5 *
234 Programming: Programming Contours