HEIDENHAIN TNC 320 (340 55x-03) - Manual (Page 147)

HEIDENHAIN TNC 320 147
6.3 Cont
our Appr
oac
h
and Depar
tur
e
Approaching on a circular arc with tangential
connection from a straight line to the contour:
APPR LCT
The tool moves on a straight line from the starting point P
S
to an
auxiliary point P
H
. It then moves to the first contour point P
A
on a
circular arc. The feed rate programmed in the APPR block is effective
for the entire path that the TNC traversed in the approach block (path
P
S
to P
A
).
If you have programmed the coordinates of all three principal axes X,
Y and Z in the approach block, the TNC moves the tool from the
position defined before the APPR block simultaneously in all three
axes to the auxiliary point P
H
and then, only in the working plane, from
P
H
to P
A
.
The arc is connected tangentially both to the line P
S
–P
H
as well as to
the first contour element. Once these lines are known, the radius then
suffices to completely define the tool path.
 Use any path function to approach the starting point P
S
.
 Initiate the dialog with the APPR/DEP key and APPR LCT soft key:
 Coordinates of the first contour point P
A
 Radius R of the circular arc. Enter R as a positive value.
 Radius compensation RR/RL for machining
Example NC blocks
X
Y
10
20
P
A
RR
P
S
R0 P
H
RR
RR
40 10
R10
35
20
7 L X+40 Y+10 RO FMAX M3 Approach P
S
without radius compensation
8 APPR LCT X+10 Y+20 Z-10 R10 RR F100 P
A
with radius comp. RR, radius R=10
9 L X+20 Y+35 End point of the first contour element
10 L ... Next contour element