HEIDENHAIN TNC 620 User Manual page 245

Important positions for approach and departure
Starting point P
S
You program this position in the block before the APPR block.
P lies outside the contour and is approached without radius
S
compensation (G40).
Auxiliary point P
H
Some of the paths for approach and departure go through an
auxiliary point P that the TNC calculates from your input in the
H
APPR or DEP block. The TNC moves from the current position
to the auxiliary point P
have programmed G00 (positioning at rapid traverse) in the last
positioning block before the approach function, the TNC also
approaches the auxiliary point P
First contour point P and last contour point P
A
You program the first contour point P
last contour point P can be programmed with any path function.
E
If the APPR block also includes the Z coordinate, then the TNC
moves the tool simultaneously to the first contour point P
End point P
N
The position P lies outside of the contour and results from
N
your input in the DEP block. If the DEP block also includes the Z
coordinate, then the TNC moves the tool simultaneously to the
end point P .
N
Abbreviation
APPR
DEP
L
C
T
N
When moving from the actual position to the
auxiliary point P
the programmed contour will be damaged. Use the
test graphics to check.
With the APPR LT, APPR LN and APPR CT functions,
the TNC moves the tool from the actual position to
the auxiliary point P
that was last programmed. With the APPR LCT
function, the TNC moves to the auxiliary point P
the feed rate programmed with the APPR block. If no
feed rate is programmed before the approach block,
the TNC generates an error message.
HEIDENHAIN | TNC 620 | ISO Programming User's Manual | 9/2016
Approaching and departing a contour
at the feed rate last programmed. If you
H
at rapid traverse.
H
E
in the APPR block. The
A
Meaning
Approach
Departure
Line
Circle
Tangential (smooth connection)
Normal (perpendicular)
the TNC does not check whether
H
at the feed rate/rapid traverse
H
.
A
at
H
6.3
R0=G40; RL=G41; RR=G42
245
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