Fanuc Series 15i/150i-MA (Programming) Operators Manual

D.NOMOGRAPHS APPENDIX B-63324EN/03
- 768 -
D.1 INCORRECT THREADED LENGTH
The leads of a thread are generally incorrect in δ
1
and δ
2
, as shown in
Fig. D.1 (a), due to automatic acceleration and deceleration.
Thus distance allowances must be made to the extent of ´
1
and ´
2
in
the program.
Explanations
- How to determine ´
2
)mm(V
1
T
2
=δ ¥¥¥¥¥¥¥ (1)
RL
60
1
V =
T
1
: Time constant of servo system (sec)
V : Cutting speed (mm/sec)
R : Spindle speed (min
-1
)
L : Thread feed (mm)
Time constant T
1
(sec) of the servo system:
Usually 0.033 s.
- How to determine ´
1
V
1
T
t
exp
1
T
1
Tt
1
+=δ ¥¥¥¥¥¥ (2)
=α
1T
t
exp
¥¥¥¥¥¥ (3)
T
1
: Time constant of servo system (sec)
V : Cutting speed (mm/sec)
Time constant T
1
(sec) of the servo system: Usually
0.033 s.
Fig. D.1(a) @Incorrect thread position
δ
1
δ
2

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