
A-78640E
Sheet
Title
Draw
No.
04 Feb.08.’03 Part of (4) is added or modified. Addition of 2.16.5
03 Jul.02.’02 A. Fukumoto Part of (3) is added or modified. T.Endo
02 May.13.’02 A. Fukumoto Addition of Tool Radius control for 5-axis machining etc T.Endo
Ed. Date Design Description
Date Jan.25.’02 Desig. A.Fukumoto Apprv. T.Endo
FANUC Series 16i /18i -TB
Specifications of AI High-Precision Contour Control /
I Nano High-Precision Contour control
114/190
2.23.3 Deceleration Based on the Acceleration along Each Axis
As shown below, when a curve is formed by very short successive line segments,
there is no significant feedrate difference along each axis at each corner.
Consequently, the tool need not be decelerated to compensate for feedrate
differences. When taken as a whole, however, successive feedrate differences
generate a large acceleration along each axis.
In this case, the tool must be decelerated to minimize the stress and strain
imposed on the machine, as well as the machining error that may result from
such excessive acceleration.
The decelerating speed is a feedrate by which the acceleration of each axis of all
axes becomes below a permissible acceleration which is set by parameter
No.8470.
The deceleration speed is determined at each corner. The deceleration speed is
calculated respectively of the starting point and the end point of the block, and
the speed in the small becomes an actual feedrate.
• Example
In the example shown below, the tool is accelerated too quickly from N2 to N4
and from N6 to N8 (as indicated by the dashed–line inclinations in the feedrate
graphs) when automatic feedrate control is not used. So, the tool is decelerated.
X-axis
feedrate
N1
N2
Y
N3
N4
N6
N7
N8
Y- ax i s
feedrate
Tangen
feedrate
N1 N5 N9
N1 N5 N9
N9
N5
Fig. 2.23.3 (a) Example of feedrate determination based on acceleration