HEIDENHAIN TNC 620 User Manual page 463

Definition of a normalized vector
A normalized vector is a mathematical quantity with a value of 1
and any direction. The TNC requires up to two normalized vectors
for LN blocks, one to determine the direction of the surface-normal
vector, and another (optional) to determine the tool orientation
direction. The direction of a surface-normal vector is determined by
the components NX, NY and NZ. With an end mill and radius cutter,
this direction is perpendicular from the workpiece surface to be
machined to the tool datum PT, and goes through PT' or PT in the
case of a toroid cutter (see figure). The direction of tool orientation
is determined by the components TX, TY and TZ.
The coordinates for the X, Y, Z positions and the
surface-normal components NX, NY, NZ, as well as
TX, TY, TZ must be in the same sequence in the NC
block.
Always indicate all of the coordinates and all of the
surface-normal vectors in an LN block, even if the
values have not changed from the previous block.
TX, TY and TZ must always be defined with
numerical values. You cannot use Q parameters.
Calculate the normal vectors as exactly as possible
and output them with a sufficient number of decimal
places, in order to avoid interruptions in the feed rate
during machining.
3-D compensation with surface-normal vectors is
only effective for coordinates in the main axes X, Y, Z.
If you insert a tool with an oversize (positive delta
value), the TNC outputs an error message. You can
suppress the error message with the M function
M107.
Further Information:
vector, page 463
The TNC will not display an error message if an
entered tool oversize would cause damage to the
contour.
Machine parameter toolRefPoint (no. 201302)
defines whether the CAD system has calculated the
tool length from the center of sphere PT or the south
pole of sphere PSP (see figure).
HEIDENHAIN | TNC 620 | Conversational Programming User's Manual | 10/2015
Three-dimensional tool compensation
Definition of a normalized
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