HEIDENHAIN CNC Pilot 4290 V7.1 - Manual (Page 244)

244
4.22 Thr
e
ad Cy
cles
Thread single path G33
G33 conducts a single thread cut. The direction of the single thread
path is as desired (longitudinal, tapered or transverse threads; internal
or external threads). You can make successive threads by
programming G33 several times in succession.
Position the tool in front of the thread by the run-in length B if the slide
must accelerate to the feed rate. And remember the run-out length P
before the end point of thread if the slide has to be decelerated.
Run-in length B: The slide requires a run-in distance at the start of
thread in order to accelerate to the programmed feed rate before
starting the actual thread.
Run-out length P: The slide needs an overtravel at the end of the
thread to decelerate again. Remember that the paraxial line P needs
overtravel even with an oblique thread run-out
If the thread is made with look-ahead, the CNC PILOT checks the run-
in and run-out length. If the paths are shorter than shown in the
following equation, the control issues a warning.
You can calculate the minimum run-in and run-out length with the
following equation.
Example: G33
. . .
N1 T5 G97 S1100 G95 F0.5 M3
N2 G0 X101.84 Z5
N3 G33 X120 Z-80 F1.5 [thread single path]
N4 G33 X140 Z-122.5 F1.5
N5 G0 X144
. . .
Parameters
X End point of thread (diameter)
Z End point of thread
F Feed per revolution (thread pitch)
B Run-in length (length of the acceleration path)—default :0
P Run-in length (length of the acceleration path)—default: 0
C Starting angle (thread start is defined with respect to
rotationally nonsymmetrical contour elements)—(default: 0)
Q Number of the spindle
H Reference direction for thread pitch (default: 0)
„ H=0: Feed rate on the Z axis for longitudinal and taper
threads up to a max. angle of +45°/–45° to the Z axis
„ H=1: Feed rate on the X axis for transverse and taper
threads up to a max. angle of +45°/–45° to the X axis
„ H=3: Contouring feed rate
E Variable pitch (default: 0)
„ E=0: Constant pitch
„ E>0: Increases the pitch per revolution by E
„ E<0: Decreases the pitch per revolution by E
Smooth threading switched off
Run-in length: B = 0.75 * (F*S)² / a + 0.15
Run-out length: P = 0.75 * (F*S)² / e + 0.15
Smooth threading switched on