Siemens SINUMERIK 840D sl Function Manual page 172

Detailed description
2.3 Continuous -path mode
Note
Rounding cannot and should not replace the functions for defined smoothing: RND, RNDM,
ASPLINE, BSPLINE, CSPLINE.
If a rounding movement initiated by G641, G642, G643, G644 is interrupted, the corner point
of the original contour will be used for subsequent repositioning, rather than the interruption
point.
Rounding is initiated by shortening discontinuously adjoining blocks and inserting one or two
intermediate blocks at this point. The original block boundary is removed and can no longer
be used for synchronization conditions (e.g., auxiliary function output parallel to motion, stop
at end of block).
With rounding, all synchronization conditions are best referred to the end of the shortened
first block and not to the end of the intermediate rounding block. The following block is thus
not started and with a stop at end of block, the contour of the following block can still be
changed.
Rounding is only performed if the block transition is to be traveled with finite velocity. The
maximum path speed is influenced by the curvature. The maximum acceleration values of
the axes are not exceeded. A block without traverse information for the path axes requires
velocity "zero" and therefore no rounding.
Rounding is also used if the traversal of the block transition requires a velocity that lies below
the permissible velocity at the end of the block according to G64 (see overload factor). This
means that very small knees in the contour (e.g., 0.5 degrees) can be overtraveled directly.
No intermediate rounding blocks
An intermediate rounding block is not inserted in the following situations:
1
2
20
The axis stops between the two blocks. This occurs when ...
1 The auxiliary function output is programmed before the movement in the following block.
2 The following block does not contain a path movement.
3 An axis, which was previously a positioning axis traverses as a path axis for the first time
in the following block.
4 An axis, which was previously a path axis traverses as a positioning axis for the first time
in the following block.
5 The previous block moves geometry axes and the following block does not.
6 The following block moves geometry axes and the previous block does not.
7 Prior to thread cutting: The following block uses G33 as a preparatory function and the
previous block does not.
8 A change is made between BRISK and SOFT.
9 Axes involved in the transformation are not completely assigned to the path motion (e.g.,
for oscillation, positioning axes)
The rounding block would slow down part program execution. This occurs when ...
1 A rounding block is inserted between very short blocks. Since each block requires at
least one interpolation cycle, the added intermediate block would double the machining
time.
Basic logic functions: Continuouspath Mode, Exact Stop, LookAhead (B1)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0