
3.INTERPOLATION FUNCTION NC FUNCTIONS B-63322EN/03
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3.5 HELICAL INTERPOLATION (G02,G03)
Helical interpolation which moved helically is enabled by specifying
up to two other axes which move synchronously with the circular
interpolation by circular commands.
The basic command method involves simply adding a move command
for one or two axes, other than circular interpolation axes, to a circular
interpolation command (see II-3.4).
As the feedrate, either a feedrate tangent to an arc or a tangential
feedrate determined by also considering movement along the linear
axes can be specified. The feedrate to be specified can be selected by
setting bit 2 (HTG) of parameter No. 1401. If HTG is set to 0, a feedrate
along an arc is specified by an F command. Therefore, the feedrate on
a linear axis is as follows:
arccircularofLength
axislinearofLength
F ×
Determine the feedrate so that the linear axis feedrate does not exceed
any of the limit values
Fig.3.5 (a) Feedrate When Parameter HTG = 0
When bit 2 (HTG) of parameter No. 1401 is set to 1, the speed
command specifies the feedrate along the actual tool path, including
movement along the linear axis.
In this case, the feedrate along the arc on the plane is:
22
)()( axislinearofLengtharccircularofLength
arccircularofLength
F
+
×
The feedrate along the linear axis is:
22
)()( axislinearofLengtharccircularofLength
axislinearofLength
F
+
×
Z
Y
X
The feedrate along the circumference of two
circular interpolated axes is the specified feedrate.
Tool path