Siemens SINUMERIK 828D Function Manual page 1481

W1: Tool offset
18.5 Tool radius compensation 2D (TRC)
Figure 18-25 Overshoot with DISC depending on contour angle
G451 (intersection)
If G function G451 is active, the position (intersection) resulting from the path lines (straight line, circle or helix
only) located at a distance of the tool radius to the programmed contour (center-point path of the tool), is
approached. Spines and polynomials are never extended.
Very pointed outside corners
Where outside corners are very pointed, G451 can result in excessive idle paths. Therefore, the system switches
automatically from G451 (intersection) to G450 (transition circle, with DISC where appropriate) when outside
corners are very pointed.
The threshold angle (contour angle) for this automatic switchover (intersection point → transition circle) can be
specified in the machine data:
MD20210 $MC_CUTCOM_CORNER_LIMIT (Max. angle for compensation blocks with tool radius
compensation).
Basic Functions
1481
Function Manual, 09/2011, 6FC5397-0BP40-2BA0