Monitoring Of Path Curvature; Selection/Deselection Of 3D Trc - Siemens SINUMERIK 840D sl Function Manual

A variable tool orientation in a block that is shortened owing to an inside corner is also treated
in the same way as described in Subsection "Behavior at inside corners" for 3D milling, i.e.
the entire change in orientation is executed in the shortened block. Consequently, the
functional relationship between path tangent, surface normal and tool orientation also changes.
This results in new, previously nonexistent singularities or impermissible side angles (at points
which are virtually singular) occurring in the shortened block. If this type of situation is detected
during processing of an inside corner, the machining operation is aborted with an alarm. No
block division takes place at the singular points since the compensatory motions this would
involve frequently cause contour violations and the change in machining side on the tool is not
generally intended or even foreseen by the user. The alarm is also output during examination
of an inside corner if the singularity occurs in the second of the two blocks without the transition
to the next block being considered. The system does not therefore detect that a block of this
type will form an inside corner in conjunction with the following block and that the singularity
would be eliminated again by the second block reduction.
The surface normal vector n
contrast to the tool orientation, the change in orientation that may need to be executed for this
vector will not be imaged onto the reduced traversing interval. This is necessary because a
surface other than that programmed would be machined. Unlike the tool orientation, no
problems arise as the result of an abrupt change in the surface normal vector at a block
transition since it does not reflect any axis motions.
Analogously to 3D circumferential milling, (see Section "Behavior at inside corners
(Page 780)"), the two traversing blocks that form an inside corner must contain contact points.
There is no evaluation of several traversing blocks (i.e. no bottleneck detection), CDON/CDOF
are not evaluated. If no contact point can be found, the machining operation is aborted with
an alarm (risk of collision).
23.3.7

Monitoring of path curvature

The path curvature is not monitored, i.e. the system does not usually detect any attempt to
machine a concave surface that is curved to such a degree that the tool currently in use is not
capable of performing the machining operation. A possible exception are blocks that are split
owing to a singularity. The transition between the two partial blocks created after the split is
then treated like an inside corner. Except for such special cases, the user is responsible for
ensuring that only tools that can machine along the entire contour without violating it are used.
23.4

Selection/deselection of 3D TRC

The following commands are used to select/deselect 3D tool radius compensation for
circumferential milling or face milling:
● CUT3DC (circumferential milling)
● CUT3DFS (face milling)
● CUT3DFF (face milling)
● CUT3DF (face milling)
Special functions
Function Manual, 01/2015, 6FC5397-2BP40-5BA2
W5: 3D tool radius compensation - 840D sl only
is not affected by the reduction of a block. This means that in
F
23.4 Selection/deselection of 3D TRC
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