
7.FEEDRATE CONTROL/ACCELERATION AND DECELERATION CONTROL B-63943EN-1/02
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- Speed control with the acceleration on each axis
When consecutive small lines are used to form a curve, as in the
example shown in the figure below, the feedrate differences on each
axis at the individual corners are not very large. Thus, deceleration
with the feedrate differences is not effective. Consecutive small
feedrate differences, however, cause a large acceleration on each axis,
as a whole.
In such a case, deceleration can be performed to reduce the impact on
the machine and the machining error caused by too large an
acceleration. The deceleration feedrate is determined to be the
feedrate that does not cause the acceleration on each axis to exceed the
permissible acceleration set for parameter No. 1737.
The deceleration feedrate is determined for each corner. The actual
feedrate is the smaller of the deceleration feedrate determined at the
start point of the block and that determined at the end point.
Depending on the specified figure, a very low deceleration feedrate
may be calculated. In such a case, the lower feedrate limit can be set
in parameter No. 1738 to prevent the feedrate from being decreased
too much.
In the following example, the acceleration (gradient of the broken line
in the feedrate graph) at too large at corners N2 to N4 and N6 to N8
and, therefore, deceleration is performed.