Siemens SINUMERIK 840D sl Function Manual page 1838

Detailed Description
2.3 Tool cutting edge
2.3.10 Tools with a relevant tool point direction
Up to SW 4.x
The change from G40 to G41/G42 or vice versa is treated as a tool change for tools with
relevant tool point direction. This causes a preprocessor stop when a transformation (e.g.,
TRANSMIT) is active, and may lead to deviations from the intended part contour.
SW 5 and higher
The following changes have been made:
1. The change from G40 to G41/G42 or vice versa is no longer treated as a tool change.
Therefore, a preprocessor stop no longer occurs with TRANSMIT.
2. The straight line between the tool edge center points at the block start and block end is
used to calculate intersection points with the approach and retraction block. The
difference between the tool edge reference point and the tool edge center point is
superimposed on this movement.
For approach and/or retraction with KONT, the movement is superimposed in the linear
subblock of the approach or retraction movement. Therefore, the geometric conditions for
tools with or without relevant tool point direction are identical. Deviations from previous
behavior occur only in relatively rare cases where the approach or retraction block does
not intersect with an adjacent motion block:
Figure 2-14 Retraction behavior for tool with relevant tool point direction
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Basic logic functions: Tool Offset (W1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0