CNC Z32 - Programming Guide (LATHES)
G906: Facial threadings
For facial threadings:
G906 X.. Z.. NZ.. NX.. K.. E.. NS.. (J..) (NF..) (I..) (NG..) (NU..)
The meaning of the parameters becomes the following:
NX
“On air” coordinate of the first positioning along X
X
Coordinate of the threading final point along X
Z
Coordinate of the nominal external surface of the thread
NZ
Selects the direction of the machining
NZ=1
if the tool is oriented toward Z-
NZ=-1
if the tool is oriented toward Z+
NG
Percentage taper: positive if Z increases
J
Distance between tool and workpiece during the return path from a pass; if not programmed or
equal to zero, a default value of J=2 is assumed
K
Thread pitch, ALWAYS in millimeters
NS
Number of roughing passes
NF
Number of finishing passes
I
Number of starting worms
E
Thread
type
E =100
Metric screw 60° UNI 4535-64
E =300
Whitworth screw UNI 2709
E =500
Trapezoidal screw UNI 2902
E =700
Square section screw (depth 0.5*K/NF)
E =900
Generic screw (custom)
NU
Thread depth (in mm, used only on custom threadings)
All other parameters maintain the same meaning.
It is possible to execute plane and taper threadings, with positive or negative X.
The NG parameter is computed with the formula:
100
1
2
)
(
⋅
∆
⋅
⋅
−
=
X
Ziniziale
Zfinale
NG
Where:
Ziniziale
is the Z coordinate of thread start
Zfinale
is the Z coordinate of thread end
∆
X
is the length (always positive) of the X segment going from Ziniziale to Zfinale
Z
X
2
3
1
X
Z
J
98