Siemens SINUMERIK 840D sl Function Manual page 900

Detailed description
2.4 Frames
Rotations
Depending on the machining task, it is necessary to take into account not only a zero offset
(whether as frame or as tool length) when using a rotary toolholder or table, but also a
rotation. However, the activation of an orientational toolholder never leads directly to a
rotation of the coordinate system.
If only the tool can be rotated, a frame can be defined for it using TOFRAME or TOROT.
With rotary tables (kinematics types P and M), activation with TCARR similarly does not lead
to an immediate rotation of the coordinate system, i.e., even though the zero point of the
coordinate system is offset relative to the machine, while remaining fixed relative to the zero
point of the workpiece, the orientation remains unchanged in space.
If the coordinate system needs to be fixed relative to the workpiece, i.e., not only offset
relative to the original position but also rotated according to the rotation of the table, then
PAROT can be used to activate such a rotation in a similar manner to the situation with a
rotary tool.
With PAROT, the translations, scalings and mirroring in the active frame are retained, but the
rotation component is rotated by the rotation component of an orientational toolholder
corresponding to the table.
Up to and including SW P6.1, the rotation activated by PAROT is calculated in the
programmable frame ($P_PFRAME), thus changing its rotation component.
With SW P6.2 and higher, the entire programmable frame remains unchanged, including its
rotation component.
The rotation component, which describes the rotation of the tool table, is then entered into
system frame $PARTFR, if bit 2 of machine data
MD28082 $MC_MM_SYSTEM_FRAME_MASK
is set.
Alternatively, the basic frame described in machine data
MD20184 $MC_TOCARR_BASE_FRAME_NUMBER
can also be used.
As with the note made in the description of the table offset, the second alternative here is not
recommended for use with new systems.
The rotation component of the part frame can be deleted with PAROTOF , independently of
whether this frame is found in a basic or a system frame.
The translation component is deleted when a toolholder, which does not produce an offset, is
activated or a possibly active orientational toolholder is deselected with TCARR=0.
PAROT or TOROT take into account the overall orientation change in cases where the table or
the tool are oriented with two rotary axes. With mixed kinematics only the corresponding
component caused by a rotary axis is considered. It is thus possible, for example, when
using TOROT, to rotate a workpiece such that an oblique plane lies parallel to the XY plane
fixed in space, whereby rotation of the tool must be taken into account in machining where
any holes to be drilled, for example, are not perpendicular to this plane.
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Basic logic functions: Axes, coordinate systems, frames (K2)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0