
4.INTERPOLATION FUNCTIONS PROGRAMMING B-63784EN/01
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- Maximum cutting feedrate along each axis
With the conventional specification, the specified feedrate F during
NURBS interpolation is clamped to the minimum value of the
maximum cutting feedrate (parameter No. 1422) of each axis as
indicated by the expression below.
))(),(),(),(),(Min(
maxmaxmaxmaxmax
BFAFZFYFXFF ≤
So, when the maximum cutting feedrate of a rotation axis F
max
is small,
the specified feedrate F during NURBS interpolation may be clamped
to F
max
of the rotation axis, resulting in an increase in machining time.
This function changes the method of clamping the specified feedrate F
as described below.
The specified feedrate F is clamped so that the component of F along
each axis does not exceed the maximum cutting feedrate (parameter No.
1422) of each corresponding axis (Fig. 4.17.1(a)).
1 segment
F(0)
F(1)
F(t)
F
F
F
Fig. 4.17.1(a)
An example of NURBS interpolation using the five axes X, Y, Z, A,
and B is explained below.
Here, the feedrate F is represented by vector F(t) (where t changes from
0 to 1 in one segment). Let F
x
(t), F
y
(t), F
z
(t), F
a
(t), and F
b
(t) be the
components of the individual axes. Then, the following expression is
given:
))(),(),(),(),(()( tFtFtFtFtFtF
bazyx
= (t = 0 to 1 in one segment)
Then,
)(tFF =
At this time, F is clamped so that the following states are satisfied at all
times in the segment:
)()(
)()(
)()(
)()(
)()(
max
max
max
max
max
BFtF
AFtF
ZFtF
YFtF
XFtF
b
a
z
y
x
≤
≤
≤
≤
≤
In other words, the conditions below must be satisfied when the
clamped feedrate F is multiplied by the proportion of each axis
component (such as
)(
)(
tF
tF
x
):