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FANUC Series 16
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/18
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-TA/TB
Specifications of High-Precision Contour
Control forComplex Lathe
2001.02.14 A.Fukumoto
02 2001.10.04
Description of Cs axis and rotary axis are added.
2.17.4 Feedrate determination based on an allowable acceleration during circular
interpolation
When a block specifies circular feed per minute and bit 3 (CIR) of parameter No. 8475 is set
to 1, the feedrate of the tool is automatically determined so that the acceleration along each
axis does not exceed an allowable acceleration.
The allowable acceleration is determined from the maximum cutting feedrate (set in parameter
No. 1432, No. 1430, or No. 1422) and the time needed to reach the maximum cutting feedrate
(set in parameter No. 8470).
During circular interpolation, the tool is controlled so that it always moves along the path at
the specified feedrate. At this time, the feedrate is clamped so that a synthetic acceleration of
two axes of circular interpolation should not exceed the small of permissible accelerations of
each axis.
2.17.5 Feedrate determination based on cutting load
This function can be used when bit 4 (ZAG) of parameter No. 8451 is set to 1.
Fig. 2.17.5 (a) When the tool is moving up along the Z–axis
θ
Fig. 2.17.5 (b) When the tool is moving down along the Z–axis
Cutting the workpiece with the end of the cutter (Fig. 2.17.5 (b)) incurs a greater resistance
than when cutting the workpiece with the side of the cutter (Fig. 2.17.5 (a)). Therefore, for
(Fig. 2.17.5 (b)), the tool must be decelerated. To calculate the required degree of feedrate
deceleration, the automatic feedrate control function uses the angle of downward movement
of the tool along the Z–axis.
When the tool is moving down along the Z–axis, the angle (θ) of downward movement
formed by the XY plane and cutter path is as shown in the Fig. 2.17.5 (b). The angle of
downward movement is divided into four areas, with an override value for each area specified
in a parameter, as follows:
Area 2: Parameter No. 8456
Area 3: Parameter No. 8457
Area 4: Parameter No. 8458