Siemens SINUMERIK 840D sl, Function Manual

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Detailed Description
2.4 Tool radius compensation 2D (TRC)
Basic logic functions: Tool Offset (W1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
91
2.4.13 G461/G462 Approach/retract strategy expansion
Function
In certain special geometrical situations, extended approach and retraction strategies,
compared with the previous implementation, are required in order to activate or deactivate
tool radius compensation (see figure below).
Note
The following example describes only the situation for deactivation of tool radius
compensation. The response for approach is virtually identical.
Example
G42 D1 T1
; Tool radius 20 mm
...
G1 X110 Y0
N10 X0
N20 Y10
N30 G40 X50 Y50
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Figure 2-39 Retraction behavior with
G460
The last block with active tool radius compensation (
N20
) is so short that an intersection no
longer exists between the offset curve and the preceding block (or a previous block) for the
current tool radius. An intersection between the offset curves of the following and preceding
blocks is therefore sought, i.e., between
N10
and
N30
in this example. The curve used for
the retraction block is not a real offset curve, but a straight line from the offset point at the
end of block
N20
to the programmed end point of
N30
. The intersection is approached if one
is found. The colored area in the figure is not machined, although the tool used would be
capable of this.