Machines With Hirth-Coupled Axes - HEIDENHAIN TNC 620 User Manual

MEASURE KINEMATICS (Cycle 451, DIN/ISO: G451, option) 18.4

Machines with Hirth-coupled axes

Danger of collision!
In order to be positioned, the axis must move out of
the Hirth grid. So remember to leave a large enough
safety clearance to prevent any risk of collision
between the touch probe and calibration sphere.
Also ensure that there is enough space to reach the
safety clearance (software limit switch).
Define a retraction height Q408 greater than 0 if
software option 2 (M128, FUNCTION TCPM) is not
available.
If necessary, the TNC rounds the calculated
measuring positions so that they fit into the Hirth grid
(depending on the start angle, end angle and number
of measuring points).
Depending on the machine configuration, the TNC
cannot position the rotary axes automatically. If this
is the case, you need a special M function from the
machine tool builder enabling the TNC to move the
rotary axes. The machine tool builder must have
entered the number of the M function in machine
parameter mStrobeRotAxPos for this purpose.
The measuring positions are calculated from the start angle, end
angle and number of measurements for the respective axis and
from the Hirth grid.
Example calculation of measuring positions for an A axis:
Start angle Q411 = –30
End angle Q412 = +90
Number of measuring points Q414 = 4
Hirth grid = 3°
Calculated stepping angle = ( Q412 – Q411 ) / ( Q414 – 1 )
Calculated stepping angle = = ( 90 – –30 ) / ( 4 – 1 ) = 120 / 3 = 40
Measuring position 1 = Q411 + 0 * stepping angle = -30° --> -30°
Measuring position 2 = Q411 + 1 * stepping angle = +10° --> 9°
Measuring position 3 = Q411 + 2 * stepping angle = +50° --> 51°
Measuring position 4 = Q411 + 3 * stepping angle = +90° --> 90°
TNC 620 | User's Manual Cycle Programming | 3/2014
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