HEIDENHAIN TNC 426 CB, Technical Manual

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6 – 364 HEIDENHAIN Technical Manual TNC 426, TNC 430
Inside corners
On inside corners, having probed the last point (1), the touch probe continues
to oscillate in the same scanning direction, but changes direction because it
cannot get clear. It then moves down the resultant straight line until it either
gets clear or reaches one of the limits TRAVEL (2) or PP.INT (3).
The touch probe moves in the reverse scanning direction to get clear again. If
the programmed probe point interval PP.INT (4) is too small for the probe to
clear, it travels in negative direction by up to the value of MP6240 (max. stylus
deflection). As soon as the touch probe is clear it returns to the contour (5) in
the reverse travel direction. The new scanning direction is defined by the
probed points (1) and (5).
If, after it backs off by the travel defined in MP6240, the touch probe is not
clear of the surface (6), it will retract in the positive direction of the probe axis
(e.g. Z+). If the stylus is still deflected after it reaches the clearance height
(See "Scanning cycles” on page 6 – 361), “Range” cycle), the scanning
sequence is aborted and an error message is displayed.
Optimizing the
scanning sequence Preparation:
7 7 7 7 Set up a flat workpiece with vertical side and smooth top in the machining
plane (e.g. XY plane).
7 7 7 7 Select the MANUAL or ELECTRONIC HANDWHEEL mode of operation.
7 7 7 7 Probe the surface with the surface = “datum” function and enter +0 mm for
the datum plane.
7 7 7 7 For the following machine parameters select the default setting:
• MP6210 = 5 [1/s] Oscillations in normal direction
• MP6230 = 30 [mm/min] Feed rate in normal direction
• MP6240 = 5 [mm] Maximum deflection of the stylus
7 7 7 7 Enter an NC program with the scanning cycles “range” and “meander,” and
specify the scanning direction X and the point spacing 1 mm.
2
3
1
4
5
6
PP.INT
TRA
VEL
Contour
Max. st
ylus
deflection MP6240
PP.INT