2.8.25, 8 Automatic Threading Cycle (G 76) (Cent’d)
EXA.MPLE :
GOO X66. Z115. ;
G76 x56.2 Z30. K3.9 D2. F6. A60 ;
GOO . . .
-x
I
t
1
I
Single block operation
. Executing G70 through G76 at SINGLE BLOCK
switch ON brings the following results.
G70, G71, G72,
G 73, G 74, G 75
I
Program Stops at Every Block.
A
r—- —-~
Program stops
G 76
< ;tr:::; :Y.le
I
IS finished.
64.im~
56. 2 1)1.1
(a)
.2
30.
\
),.
,,.
1
60”
(b)
~
~390
/
a
Depth of cut for each cycle when
a (fixed amount) is O. 2 mm
1st cycle —1.700mm
2nd cycle — 2.528 mm
3rd cycle — 3.164 mm
4th cycle
— 3.700 mm
5th cycle
— 3.900 mm
Though D20(I (2.0 mm) is programmed, the
actual depth of cut becomes 1.7 mm by the
calculation of = D because of the dif–
ference between ~= D and (K - a) .
2. 8.25.9 Precautions
in Programming G 70 through G 76
Symmetrical pattern
The symmetrical four patterns can be command-
ed by each of G71 to G76.
Signs of U, W and I should be properly specifi-
ed in the finishing shape program for G71 to
G73.
(See Fig. 2.8.25.33)
Command position of (X, Z) or (U, W) with re-
spect to position A should be properly specifi-
ed for G74 to G76.
+x
~–, ~--,]–
u-, w-. 1–
LJ+,W’-.1-
L’–,w , I+
I
-z
Fig. 2.54 Four patierns of G 76
Prohibition of MD I mode
. Operation in MD I mode cannot be made while
multiple repetitive cycles ( G70 through G76)
are executed.
. Multiple repetitive cycles (G 70 through G 76)
cannot be written–in Through the operation in
MDI mode.
112
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