Siemens SINUMERIK 840Di Function Manual page 1726

Detailed Description
2.4 Tool: Tool radius compensation 2D (TRC)
Fig. 2-18
Note
The figure shows that a straight line bordering on the contour quadrant, e.g., to X20 Y-20,
would be violated with KONTC on retraction/approach to X0, Y0.
2.4.4 Smooth approach and retraction
Meaning
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.
2-46
Differences between KONTT and KONTC
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Tool Compensation (W1)