
3. α SERIES PARAMETER ADJUSTMENT B-65150E/04
− 80 −
When the feedrate at an arc is reduced using the arc radius based
feedrate clamp function, figure precision improves. However, a longer
machining time is required as a side effect. Fig. 3.4.3 (m) shows a
tangent feedrate and processing time when the arc radius based feedrate
clamp function is not used with the adjustment program used in (5) and
later. Fig. 3.4.3 (m) indicates that the tangent feedrate remains to be
F4000. On the other hand, when feedrate reduction to F3000 at R5 mm
is specified with the arc radius based feedrate clamp function, the
tangent feedrate is reduced to F3000 at corners as shown in Fig. 3.4.3
(n), but the machining time has increased by 200 msec.
Fig. 3.4.3 (m) When the arc radius based feedrate
clamp function is not used
Fig. 3.4.3 (n) When the arc radius based feedrate clamp
function is used
[Guideline for adjustment value setting]
Empirically, the values below are adequate. For the parameter
numbers, refer to the parameter manual of each CNC.
High-rigidity small machines: F4000 for R5 (889 mm/sec
2
)
Medium-size or small machining centers with a relatively high
rigidity: F3000 for R5 (500 mm/sec
2
)
Large machines: F2500 for R5 (347 mm/sec
2
)
Large machines with a very high rigidity:
F2000 for R5 (222 mm/sec
2
)
[Actual adjustment]
Fig. 3.4.3 (o) shows the results of setting R5 mm and F3000 with
the arc radius based feedrate clamp function for Fig. 3.4.3 (k). Fig.
3.4.3 (o) indicates that the figure errors at the entries and exits of
the arc areas have been reduced.
Tangent
feedrate
X-axis
position
1900 msec
2100 msec
Tangent
feedrate
Acceleration of
acceleration/
deceleration before
interpolation
Feedrate reduction to
F3000