Siemens SINUMERIK 840DE sl Function Manual page 183

Requirement
For generic 7-axis transformation there must be at least 6 or 7 axes.
Function
Another 7th axis is required in connection with the generic 6-axis transformation which rotates
the workpiece. This 7th Axis is considered only along with transformation type 24 (generic 6-
axis transformation having 3 rotary axes that move the tool ).
The position of the 7th axis is specified according to a strategy of the CAD system and settled
with the Cartesian position (X, Y, Z) by the generic transformation in such a way that the axes
always approach the TCP position programmed with reference to the workpiece, independently
of the position of the 7th axis. If ORIWKS is active, the end orientation programmed with
reference to the workpiece is also rotated by the 7th axis. This way it is possible to program the
orientation in relation to the workpiece.
The transformation uses the 7th axis as the observed input variable.
To configure the 7th axis, the channel machine data of the 5-/6-axis transformation is extended
by one field containing the 3 components of the direction vector of the 7th axis and an axis
offset.
This gives the following advantages:
● The contour and the orientation at the workpiece can be programmed in relation to the
workpiece.
● The programmed feed is maintained in the contour, even if the 7th axis also moves.
● All the contour-related control functions can be used.
● The displayed WCS position corresponds to the programmed position.
● The transformation is configured as in generic 6-axis transformation. One can switch
between a 6-axis and a 7-axis transformation smoothly.
● In case of large radius circular interpolation, the release of singularities incorporating the 7th
axis.
Notations
Dedicated machine data exist for each general transformation and for each orientation
transformation that are differentiated by the suffixes _1, _2 etc. (e.g. $MC_TRAFO_TYPE_1,
$MC_TRAFO_TYPE_2 etc.). In the following, only the names for the first transformation are
specified, i.e. those with the suffix _1. If a transformation other than the first is parameterized,
the correspondingly modified names must be used.
Transformations
Function Manual, 06/2019, A5E47435470B AA
F2: Multi-axis transformations
3.7 Generic 5-axis transformation and variants
183