Siemens SINUMERIK 840D sl Function Manual page 1865

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).
Figure 2-30
Basic logic functions: Tool Offset (W1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Example of automatic switchover to transition circle
Detailed Description
2.4 Tool radius compensation 2D (TRC)
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