HEIDENHAIN TNC 410 - Manual (Page 101)

88 6 Programming: Programming Contours
6.5 P
ath Cont
ours — P
olar Coor
dinat
es
Circular path CTP with tangential connection
The tool moves on a circular path, starting tangentially from a
preceding contour element.
ú Polar coordinates radius PR: Distance from the arc
end point to the pole CC.
ú Polar coordinates angle PA: Angular position of the
arc end point.
Example NC blocks
12 CC X+40 Y+35
13 L X+0 Y+35 RL F250 M3
14 LP PR+25 PA+120
15 CTP PR+30 PA+30
16 L Y+0
The pole CC is not the center of the contour arc!
Helical interpolation
A helix is a combination of a circular movement in a main plane and
a linear movement perpendicular to this plane.
A helix is programmed only in polar coordinates.
Applications
■ Large-diameter internal and external threads
■ Lubrication grooves
Calculating the helix
To program a helix, you must enter the total angle through which
the tool is to move on the helix in incremental dimensions, and the
total height of the helix.
For calculating a helix that is to be cut in a upward direction, you
need the following data:
Thread revolutions n Thread revolutions + thread overrun at
the start and end of the thread
Total height h Thread pitch P x thread revolutions n
Incremental Thread revolutions x 360° + angle for
total angle IPA beginning of thread + angle for thread
overrun
Starting coordinate Z Thread pitch P x (thread revolutions +
thread overrun at the start of the thread)
X
Y
40
35
CC
30°
120°
R30 R25
Y
X
Z
CC