# FANUC Series 16/18/160/180-Model C Machining Center Operators Manual PROGRAMMING
B–62764EN/01
5. FEED FUNCTIONS
99
When acceleration/deceleration before interpolation is effective, the
relationship between the feedrate and time is as described below.
When the feedrate difference between blocks A and B along each axis is
larger than the value specified in parameter No. 1780, the feedrate is
decelerated to the corner feedrate calculated from the feedrate difference
along each axis.
Let the feedrate be F. Compare the feedrate difference along each axis
(Vc[X], Vc[Y], ...) with the value specified in parameter No. 1780, Vmax.
When the difference exceeds Vmax, calculate R as shown below.
R=
Vmax
V
c
Fc=F*
Rmax
1
N1
N2
N1 G01 G91 X80. Y20. F3000 ;
N2 X20. Y80. ;
Rmax=
Vmax
VcNX(Y)O
F*
Rmax
1
Find the maximum value for R among the calculated values for the axes.
Let it be Rmax. Then, the corner feedrate can be obtained as follows:
(Example)
From the figure, it can be seen that the feedrate differences along the X–
and Y–axes (Vc[X] and Vc[Y]) exceed Vmax. Calculate Rmax to get
Fc. When the feedrate is decelerated to Fc at the corner, the feedrate
difference along each axis do not exceed Vmax.
When this movement is specified, the feedrate along each axis is as
shown in the next figure.
D Acceleration /
deceleration before
interpolation 