214 Programming: Programming Contours
6.3 Contour Approach and Departure
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.
U Use any path function to approach the starting point P
S
U Initiate the dialog with the APPR/DEP key and APPR LCT soft key:
U Coordinates of the first contour point P
A
U Radius R of the circular arc. Enter R as a positive value
U Radius compensation RR/RL for machining
Example NC blocks
7 L X+10 Y+10 R0 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
10L...
Next contour element