Siemens SINUMERIK 840D sl Programming Manual page 335

Smoothing of tangential block transitions with G645
With G645, the smoothing movement is defined so that the acceleration of all axes involved
remains smooth (no jumps) and the parameterized maximum deviations from the original
contour (MD33120 $MA_PATH_TRANS_POS_TOL) are not exceeded.
In the case of angular non-tangential block transitions, the smoothing behavior is the same as
with G642.
No intermediate rounding blocks
An intermediate rounding block is not inserted in the following cases:
• The axis stops between the two blocks.
This occurs when:
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• The rounding block would slow down the part program execution.
This occurs:
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Fundamentals
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
11.2 Continuous-path mode (G64, G641, G642, G643, G644, G645, ADIS, ADISPOS)
The following block contains an auxiliary function output before the movement.
The following block does not contain a path movement.
An axis is traversed for the first time as a path axis for the following block when it was
previously a positioning axis.
An axis is traversed for the first time as a positioning axis for the following block when it
was previously a path axis.
The previous block traverses geometry axes and the following block does not.
The following block traverses geometry axes and the previous block does not.
Before tapping, the following block uses G33 as preparatory function and the previous
block does not.
A change is made between BRISK and SOFT.
Axes involved in the transformation are not completely assigned to the path motion
(e.g. for oscillation, positioning axes).
Between two very short blocks.
Since each block requires at least one interpolation cycle, the added intermediate block
would double the machining time.
If a block transition G64 (continuous-path mode without smoothing) can be traversed
without a reduction in velocity.
Corner rounding would increase the machining time. This means that the value of the
permitted overload factor (MD32310 $MA_MAX_ACCEL_OVL_FACTOR) affects
whether a block transition is rounded or not. The overload factor is only taken into
account for corner rounding with G641/G642. The overload factor has no effect in the
case of smoothing with G643 (this behavior can also be set for G641 and G642 by
setting MD20490 $MC_IGNORE_OVL_FACTOR_FOR_ADIS to TRUE).
Path action
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