Siemens SINUMERIK 840D sl Function Manual page 1847

2.4.4 Smooth approach and retraction
2.4.4.1 Function
Significance
The SAR (Smooth Approach and Retraction) function is used to achieve a tangential
approach to the start point of a contour, regardless of the position of the start point.
The approach behavior can be varied and adapted to special needs using a range of
additional parameters.
The two functions, smooth approach and smooth retraction, are largely symmetrical. The
following section is, therefore, restricted to a detailed description of approach; special
reference is made to differences affecting retraction.
Sub-movements
There are maximum 4 sub-movements in case of soft retraction and approach with the
following positions:
• Start point of the movement P
• Intermediate points P
• End point P
Points P
according to the parameters defined and the geometrical conditions.
On retraction, the points are traversed in the reverse direction, i.e., starting at P
at P
Basic logic functions: Tool Offset (W1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
, P
1
4
, P and P are always defined. Intermediate points P
0 3 4
.
0
0
and P
2 3
Detailed Description
2.4 Tool radius compensation 2D (TRC)
and P can be omitted,
1 2
and ending
4
59