6. Interpolation Functions
6.6 Helical Interpolation
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6.6 Helical Interpolation ; G17 to G19, G02, G03
Function and purpose
While circular interpolating with G02/G03 within the plane selected with the plane selection G code
(G17, G18, G19), the 3rd axis can be linearly interpolated.
Normally, the helical interpolation speed is designated with the tangent speed F' including the 3rd
axis interpolation element as shown in the lower drawing of Fig. 1. However, when designating the
arc plane element speed, the tangent speed F on the arc plane is commanded as shown in the
upper drawing of Fig. 1.
The NC automatically calculates the helical interpolation tangent speed F' so that the tangent
speed on the arc plane is F.
Y
Z
X
F’
F
Y
X
Start point
Start point
End point
End point
Fig. 1 Designation of helical interpolation speed
Command format
G17 G02 (G03) Xx
1
Yy
1
Zz
1
Ii
1
Jj
1
Pp
1
Ff
1
;
Helical interpolation command (Specify arc center)
G17 G02 (G03) Xx
2
Yy
2
Zz
2
Rr
2
Ff
2
;
Helical interpolation command (Specify radius (R))
G17(G18, G19)
: Plane selection (G17: XY plane, G18: ZX plane, G19: YZ plane)
G02(G03)
: Arc rotation direction
Xx
1
Yy
1
Xx
2
Yy
2
: Arc end point coordinate
Zz
1
Zz
2
: Linear axis end point coordinate
Ii
1
Jj
1
: Arc center coordinate
Pp
1
: Pitch No.
Ff
1
Ff
2
:
Feedrate
Rr
2
: Arc radius
The arc center coordinate and arc radius are commanded with an input setting input. Caution is
required for the helical interpolation command of an axis for which the input command value differs.
Command with a decimal point to avoid confusion.
Absolute or incremental values can be assigned for the arc end point coordinates and the end point
coordinates of the linear axis, but incremental values must be assigned for the arc center
coordinates.