13. Program Support Functions
13.1 Fixed Cycles
267
(k) G74 (Reverse tapping cycle)
Program
G74 Xx
1
Yy
1
Zz
1
Rr
1
Pp
1
Rr
2
(or S
1
,S
2
) ,Ii
1
,Jj
1
;
P : Dwell designation
(1) G0 Xx
1
Yy
1
(2) G0 Zr
1
(3) G1 Zz
1
Ff
1
(4) G4 Pp
1
(5) M3 (Spindle forward rotation)
(6) G1 Z – z
1
Ff
1
(7) G4 Pp
1
(8) M4 (Spindle reverse rotation)
G98
mode
G0Z
−
r
1
G99 mode No movement
G98 G99
mode mode
(4)(5)
r
1
z
1
(1)
x
1
,y
1
(7)(8)
(2)
(3)
(7) (8)
(9)
(6)
(6)
(9)
Operation
pattern
i1 j1
(1) Valid
-
(2) -
Invalid
(3) -
Invalid
(4) -
-
(5) -
-
(6) -
Invalid
(7) -
-
(8) -
-
(9) -
Valid
When r
2
= 1, the synchronous tapping mode will be entered, and when r
2
= 0, the
asynchronous tapping mode will be entered.
When G74 is executed, the override will be canceled and the override will automatically
be set to 100%. Dry run is valid when the control parameter "#1085 G00Drn" is set to "1"
and is valid for the positioning command. If the feed hold button is pressed during G74
execution, and the sequence is at (3) to (6), the movement will not stop immediately, and
instead will stop after (6). During the rapid traverse in sequence (1), (2) and (9), the
movement will stop immediately.
The operation stops at after the (1), (2) and (9) commands during single block operation.
During the G74 and G84 modal, the "Tapping" NC output signal will be output.
During the G74 synchronous tapping modal, the M3, M4, M5 and S code will not be
output.