Activating Intermediate Block Generation (Tlift) - Siemens SINUMERIK 840D sl Programming Manual

Work preparation
3.16 Axis couplings
<optimization>:
Note
Default values do not have to be programmed explicitly.
Note
1)
As the leading axes for tangential coupling, the geometry axes must be used that travel along the
programmed path in the machine coordinate system (MCS) with reference to the initial position of the
machine. For example, if swivel cycle CYCLE800 is used on a milling machine with a swivel head,
depending on how the cycle is configured, interpolation will be performed in the WCS, e.g. with the
geometry axes X and Y. The tangential coupling, however, must be defined with the geometry axes as
the leading axes, which travel along the programmed path in the MCS. For this purpose, the geometry
axes in the non-swiveled condition of the machine must be used as the leading axes.
Note
2)
The basic coordinate system (BCS) must not be rotated with respect to the MCS. For example, if the
BCS is rotated with the ROT command or with the swivel cycle CYCLE800, the tangential control is no
longer correct.
3.16.7.2

Activating intermediate block generation (TLIFT)

If the tangent change of the following axis at any position along the programmed path of the
leading axes exceeds the limit parameterized in machine data MD37400
$MA_EPS_TLIFT_TANG_STEP, further path planning will depend on the set behavior at
corners. Without use of the predefined procedure TLIFT(...), the path is traversed in
accordance with the rounding behavior programmed in connection with TANG(...) (Page 940)
and TANGON(...) (Page 943).
942
Optimization type
Data type: CHAR
Value:
"S":
"P":
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
Standard (default value)
The dynamic response of the rotary axis
has no effect on the leading axes If the dy‐
namic response of the rotary axis is greater
than required for tracking, this method is
sufficiently precise. If the dynamic re‐
sponse of the rotary axis is not great
enough to follow the change in the path
tangent, the orientation of the rotary axis
will deviate from the target orientation
along an undefined rounding clearance.
The dynamic response of the rotary axis is
considered in the path planning of the lead‐
ing axes.
For this purpose, on activation of the tan‐
gential coupling with TANGON(), two addi‐
tional parameters must be specified:
● Rounding clearance
● Angular tolerance
See Section "Activating the coupling (TAN‐
GON) (Page 943)"
Note
With kinematic transformations, we recom‐
mend using optimization method "P."
NC programming