12. FUNCTIONS TO SIMPLIFY
PROGRAMMING
B–63172EN/01
NC FUNCTION
76
When the spindle motor is controlled in rigid mode as if it were a servo
motor, a tapping cycle can be sped up.
G84
G84 X_ Z_ R_ P_ F_ ;
X_ : Hole position data
Z_ : The distance from point R to the bottom of the hole and the
position of the bottom of the hole
R_ : The distance from the initial level to point R level
P_ : Dwell time at the bottom of the hole and at point R when a
return is made
F_ : Cutting feedrate
P
Point Z
Spindle CW
Point R
Spindle CCWSpindle stop
Spindle stop
Initial level
Operation5
Operation4
Operation3
Operation1
Operation2
Operation6
Spindle
stop
P
After positioning along the X–axis, rapid traverse is performed to point
R.
Tapping is performed from point R to point Z. When tapping is
completed, a dwell is performed and the spindle is stopped. The spindle
is then rotated in the reverse direction, the tool is retracted to point R, then
the spindle is stopped. Rapid traverse to initial level is then performed.
While tapping is being performed, the feedrate override and spindle
override are assumed to be 100%.
Specify M29 S***** before a tapping command.
In feed–per–minute mode, the thread lead is obtained from the
expression, feedrate
× spindle speed. In feed–per–revolution mode, the
thread lead equals the feedrate speed.
If a tool length offset (G43, G44, or G49) is specified in the canned cycle,
the offset is applied at the time of positioning to point R.
12.2.1
Rigid Tapping (G84)
Format
Explanations
D Rigid mode
D Thread lead