Compensation On Path - Siemens sinumerik 840D sl Function Manual

If a block is shortened (inside corner), then the interpolation range of the surface normal
vector is reduced accordingly, i.e. the end value of the surface normal vector is not reached
as it would be with other interpolation quantities such as, for example, the position of an
additional synchronized axis.
In addition to the usual methods of programming orientation, it is also possible to refer the
tool orientation to the surface normal vector and path tangent vector using the addresses
LEAD (lead or camber angle) and TILT (side angle). The lead angle is the angle between
the tool orientation and the surface normal vector. The side angle is the angle between the
path tangent and the projection of the tool vector into the surface to be machined.
Specification of the angle relative to the surface normal is merely an additional option for
programming tool orientation at the block end. It does not imply that the lead and side angles
reach their programmed values before the path end point is reached.
The final tool orientation is calculated from the path tangent, surface normal vector, lead
angle and side angle at the block end. This orientation is always implemented by the end of
the block, particularly in cases where the block is shortened (at an inside corner). If the
omitted path section is not a straight line in a plane, the lead and side angles generally
deviate from their programmed values at the path end point. This is because the orientation
has changed relative to the surface normal vector or path tangent vector when the absolute
orientation of the tool is the same as at the original path end point.
2.2.3

Compensation on path

Tool longitudinal axis parallel to surface normal
A special case must be examined with respect to face milling operations, i.e. that the
machining point on the tool surface moves around. This may be the case on a torus cutter
whenever surface normal vector n
exact right angles to the surface) since it is not a single point on the tool that corresponds to
this direction, but the entire circular surface on the tool end face. The contact point is not,
therefore, defined with this type of orientation. A path point in which tool longitudinal axis and
surface normal are parallel is therefore referred to below as a singular point or a singularity.
The above case is also meaningful in practical terms, e.g. in cases where a convex surface,
which may have a vertical surface normal (e.g. hemisphere), must be machined with a
perpendicular tool (e.g. face milling with constant orientation). The machining point on the
contour remains fixed, but the machine must be moved to bring the machining point from
one side of the tool to the other.
The problem described is only a borderline case (lead angle β = 0 and side angle y = 0). If
the lead angle β = 0 and the side angle y has a low value, then the tool must be moved very
rapidly (in borderline case in steps) to keep the machining point resulting from the milling
conditions close to the arc-line forming the end face, see the following Figure.
Special functions: 3D Tool Radius Compensation (W5)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0
and tool vector w become collinear (i.e. the tool is at
F
Detailed description
2.2 Face milling
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