Siemens SINUMERIK 840D sl Function Manual page 1881

G462
If no intersection is possible between the last TRC block and a preceding block, a straight
line is inserted, on retraction with G462 (initial setting), at the end point of the last block with
tool radius compensation (the block is extended by its end tangent).
Figure 2-41
The search for the intersection is then identical to the procedure for G461.
With G462, the corner generated by N10 and N20 in the sample program is not machined to
the full extent actually possible with the tool used. However, this behavior may be necessary
if the part contour (as distinct from the programmed contour), to the left of N20 in the
example, is not permitted to be violated even with y values greater than 10 mm.
If KONT is active (travel round contour at start or end point), behavior will differ according to
whether the end point is in front of or behind the contour.
End point in front of contour
If the end point is located in front of the contour, the retraction behavior is the same as for
NORM. This feature does not change, even if the last contour block with G451 is extended
with a straight line or a circle. Additional circumnavigation strategies to avoid a contour
violation in the vicinity of the contour end point are therefore not required.
Basic logic functions: Tool Offset (W1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Retraction behavior with G462
Detailed Description
2.4 Tool radius compensation 2D (TRC)
93