HEIDENHAIN TNC 426, User Manual

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138 6 Programming: Programming Contours
6.3 Cont
our Appr
oac
h
and Depar
tur
e
Departure on a circular path with tangential
connection: DEP CT
The tool moves on a circular arc from the last contour point P
E
to the
end point P
N
. The arc is tangentially connected to the last contour
element.
U
Program the last contour element with the end point P
E
and radius
compensation.
U Initiate the dialog with the APPR/DEP key and DEP CT soft key:
U
Center angle CCA of the arc
U
Radius R of the circular arc
n
If the tool should depart the workpiece in the
direction of the radius compensation (i.e. to the
right with RR or to the left with RL): Enter R as a
positive value.
n
If the tool should depart the workpiece on the
direction
opposite to the radius compensation:
Enter R as a negative value.
Example NC blocks
Departing on a circular arc
tangentially connecting the contour
and a straight line: DEP LCT
The tool moves on a circular arc from the last contour point P
S
to an
auxiliary point P
H
. It then moves on a straight line to the end point P
N
.
The arc is tangentially connected both to the last contour element and
to the line from P
H
to P
N
. Once these lines are known, the radius R
then suffices to completely define the tool path.
U Program the last contour element with the end point P
E
and radius
compensation.
U Initiate the dialog with the APPR/DEP key and DEP LCT soft key:
U Enter the coordinates of the end point P
N
.
U Radius R of the circular arc. Enter R as a positive value.
Example NC blocks
X
Y
20
P
N
R0
P
E
RR
R8
180°
RR
23 L Y+20 RR F100 Last contour element: P
E
with radius compensation
24 DEP CT CCA 180 R+8 F100 Center angle=180°,
arc radius=8 mm
25 L Z+100 FMAX M2 Retract in Z, return to block 1, end program
X
Y
20
P
N
R0
P
E
RR
RR
12
10
R8
P
H
R0
23 L Y+20 RR F100
Last contour element: P
E
with radius compensation
24 DEP LCT X+10 Y+12 R+8 F100 Coordinates P
N
, arc radius=8 mm
25 L Z+100 FMAX M2
Retract in Z, return to block 1, end program