Modifications During The Rotation Of Turning Tools - Siemens SINUMERIK 840D sl Function Manual

2.9.2.2

Modifications during the rotation of turning tools

Description of tool orientation
Unlike milling tools, turning tools are not rotation-symmetric. This means that normally 3
degrees of freedom or three rotary axes are required to describe the tool orientation. The
concrete kinematics therefore, is independent of the machine only to the extent the desired
orientation can be set. If necessary, the third degree of freedom can be substituted by a rotation
of the tool coordinate system.
Note
The division of the orientation into one component created by the tool carrier with orientation
capability and a second component achieved via a rotation of the coordinate system is the
responsibility of the application. The control does not provide any further functionality in this
regard.
If the tool is oriented using a kinematic transformation, the user can use function ORISOLH to
calculate the orientation. (see Chapter "Calculating orientations (ORISOLH) (Page 153)").
Angle between tool insert and machining plane
If a turning tool turns by an angle against the machining plane (i.e. around an axis in the
machining plane, typically a C axis) that is not a multiple of 180°, then the configuration of the
(circular) tool cutting edge in the machining plane becomes an ellipse. It is assumed that the
deviations from the circular form arising on account of such rotations is so insignificant that they
can be ignored (tilt angle < 5°). i.e. the control always ignores the tool orientation and assumes
a circular cutting edge.
This also means that with reference to the active plane, the control accepts only a rotation by
180° as a setting deviating from the initial position. This limitation is valid for the shape of cutting
edge only. The tool lengths are always considered correctly in random spatial rotations.
A rotation by 180° around an axis in the machining plane means that while using the tool at the
same position, the spindle rotation direction with reference to the use of the unturned tool must
be inverted.
A maximum value allowed for the angle between the tool insert and the machining plane can
be specified in setting data SD42998 $SC_CUTMOD_PLANE_TOL (see also Chapter
"Parameter assignment (Page 150)").
Cutting edge position, cutting direction, and tool angle
Cutting edge position and cut direction are also not modified like the cutting edge reference
point (see below) if the tool is rotated from the plane by ± 90° (with a tolerance of app. 1°)
because then the configuration of the cutting edge is not defined in the current plane.
If a transformation is active, the active complete frame is always included in the calculation of
the actual tool rotation relative to the workpiece. If a tool carrier with orientation capability is
active, the frame is only included in the calculation if bit 21 is set in machine data MD20360
$MC_TOOL_PARAMETER_DEF_MASK (Page 150). In this case, any table component of the
Tools
Function Manual, 06/2019, A5E47435126B AA
2.9 Modification of the offset data for rotatable tools
W1: Tool offset
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