Siemens Sinumerik 840D sl Programming Manual page 259

Further information
Approach/retraction with NORM
1. Approach:
If NORM is activated, the tool will move directly to the compensated start position along a
straight line (irrespective of the preset approach angle programmed for the travel
movement) and is positioned perpendicular to the path tangent at the starting point.
2. Retraction:
The tool is perpendicular to the last compensated path end point and then moves
(irrespective of the preset approach angle programmed for the travel movement) directly
in a straight line to the next uncompensated position, e.g. to the tool change point.
Modifying approach/retract angles introduces a collision risk:
Fundamentals
Programming Manual, 01/2015, 6FC5398-1BP40-5BA2
11.2 Approaching and leaving contour (NORM, KONT, KONTC, KONTT)
Tool radius compensation
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