Siemens SINUMERIK 840DE Programming Manual page 192

Path Action
5.3 Continuous-path mode (G64, G641, G642, G643, G644)
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.
References: /FB1/Description of Functions, B1, Continuous-Path Mode.
Note
The overload factor can be set in the machine data 32310. The extent of smoothing of the
contour transitions depends on the feedrate and the overload factor. With G641 you can
specify the desired rounding area explicitly.
Rounding cannot and should not replace the functions for defined smoothing: RND, RNDM,
ASPLINE, BSPLINE, CSPLINE.
Continuous-path mode with programmable transition rounding, G641
With G641, the control inserts transition elements at contour transitions. With ADIS=... or
ADISPOS=... you can specify the extent, to which the corners are rounded. The effect of
G641 is similar to RNDM, however it is not restricted to the axes of the working plane.
Example: N10 G641 ADIS=0.5 G1 X... Y...
The rounding block must begin 0.5 mm before the programmed end of block at the earliest
and must be finished 0.5 mm after the end of the block. This setting remains modal.
G641 also operates with Look Ahead speed control. Corner rounding blocks with a high
degree of curvature are approached at reduced velocity.
5-10
Programming Manual, 10.2004 Edition, 6FC5 298-7AB00-0BP1
Fundamentals