Monitoring Of Path Curvature; Commissioning; Parameter Assignment - Siemens SINUMERIK 840D sl Function Manual

W5: 3D tool radius compensation

3.2 Commissioning

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.
Remedy: Create new/different NC program, e.g. with a smaller tolerance.
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 242)"), 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).
3.1.3.7

Monitoring of path curvature

The path curvature is only monitored for circumferential milling. As a rule, it is therefore not
detected for CUT3DF* functions when an attempt is made to process a concave surface which
is so intensively curved that machining is not possible with the tool being used. 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. Apart from these special
cases, it is the responsibility of the user to only use tools that make it possible to process every
part of the contour without contour violation. It could be helpful to use the CUT3DFD function
for this, where the differential tool is only minimally different from the original tool.
3.2 Commissioning
3.2.1

Parameter assignment

Minimal angle between path tangent and tool orientation
For the 3D-TRC, the angle between the path tangent and the tool orientation cannot
undershoot a specific limit angle.
This angle is defined in the machine data:
MD21080 $MC_CUTCOM_PARALLEL_ORI_LIMIT
252
is not affected by the reduction of a block. This means that in
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Function Manual, 06/2019, A5E47435126B AA
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