Siemens SINUMERIK 840D sl Programming Manual page 331

Further information
Continuous-path mode G64
In continuous-path mode, the tool travels across tangential contour transitions with as
constant a path velocity as possible (no deceleration at block boundaries). LookAhead
deceleration is applied before corners and blocks with exact stop.
Corners are also traversed at a constant velocity. In order to minimize the contour error, the
velocity is reduced according to an acceleration limit and an overload factor.
Note
The extent of smoothing of the contour transitions depends on the feedrate and the overload
factor. The overload factor can be set in MD32310 $MA_MAX_ACCEL_OVL_FACTOR.
Setting MD20490 $MC_IGNORE_OVL_FACTOR_FOR_ADIS means that block transitions
will always be rounded irrespective of the set overload factor.
The following points should be noted in order to prevent an undesired stop in path motion
(relief cutting):
• Auxiliary functions, which are enabled after the end of the movement or before the next
movement interrupt continuous-path mode (Exception: High-speed auxiliary functions).
• Positioning axes always traverse according to the exact stop principle, positioning window
fine (as for G601). If an NC block has to wait for positioning axes, continuous-path mode is
interrupted on the path axes.
However, intermediate blocks containing only comments, calculation blocks or subprogram
calls do not affect continuous-path mode.
Fundamentals
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
11.2 Continuous-path mode (G64, G641, G642, G643, G644, G645, ADIS, ADISPOS)
Path action
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