Siemens SINUMERIK 840Di sl - Approach and Retraction (G140 to G143, G147, G148, G247, G248, G347, G348, G340, G341); Smooth Approach and Retraction

Tool offsets
8.11 Smooth approach and retraction
Fundamentals
Programming Manual, 11/2006, 6FC5398-1BP10-2BA0
367
Note
Superfluous non-cutting tool paths can result from liftoff movements at acute contour angles.
A parameter can be used in the machine data to define automatic switchover to transition
circle in such cases.
8.11 Smooth approach and retraction
8.11.1 Approach and retraction (G140 to G143, G147, G148, G247, G248, G347, G348,
G340, G341)
Function
The soft approach and retraction function (SAR) is used to achieve a tangential approach to
the start point of a contour, regardless of the position of the start point.
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The function is mainly used in conjunction with the tool radius offset, but is not mandatory.
The approach and retraction motion consists of a maximum of 4 sub-movements:
• Start point of the movement P
0
• Intermediate points P
1
, P
2
und P
3
• End point P
4
Points P
0
, P
3
und P
4
are always defined. Intermediate points P
1
and P
2
can be omitted,
according to the parameters defined and the geometrical conditions.