Siemens SINUMERIK 828D Function Manual page 1482

W1: Tool offset
18.5 Tool radius compensation 2D (TRC)
Figure 18-26 Example of automatic switchover to transition circle
Very flat outside corners
Where outside corners are very flat, the response with G450 (transition circle) and G451 (intersection) becomes
increasingly similar. In this case, it is no longer advisable to insert a transition circle. One reason why it is not
permitted to insert a transition circle at these outside corners with 5-axis machining is that this would impose
restrictions on speed in contouring mode (G64). Therefore, the system switches automatically from G450
(transition circle, with DISC where appropriate) to G451 (intersection) when outside corners are very flat.
The threshold angle (contour angle) for this automatic switchover (transition circle → intersection point) can be
specified in the machine data:
MD20230 $MC_CUTCOM_CURVE_INSERT_LIMIT (Max. angle for intersection calculation with tool radius
compensation).
Basic Functions
1482
Function Manual, 09/2011, 6FC5397-0BP40-2BA0