Mitsubishi Electric MELDAS C6 Programming Manual page 171

13. Program Support Functions
(k) G74 (Reverse tapping cycle)
Program
G74 Xx
When r
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.
This function allows spindle acceleration/deceleration pattern to be approached to the
speed loop acceleration/deceleration pattern by dividing the spindle and drilling axis
acceleration/deceleration pattern into up to three stages during synchronous tap.
Refer to the item "d) G84 (Tapping cycle)" for details of multi-stages of the spindle
acceleration/deceleration pattern.
Yy Zz Rr Pp Ss
1 1 1 1 1
x ,y
1 1
(1)
(2)
(9)
(7) (8)
(3) (6)
G98
(4)(5)
mode
= 1, the synchronous tapping mode will be entered, and when r
2
163
,Ss Rr ,Ii ,Jj ;
1 2 2 1 1
(1) G0 Xx
(2) G0 Zr
(3) G1 Zz
r
(4) G4 Pp
1
(7)(8)
(5) M3 (Spindle forward rotation)
(6) G1 Z – z
(7) G4 Pp
(6)
(8) M4 (Spindle reverse rotation)
z
1
G98 mode G0Z − r
(9)
G99 mode No movement
G99
mode
13.1 Canned cycles
Yy
1 1
1
Ff
1 1
1
Ff
1 1
1
1
2
= 0, the