OPERATION BY Symbolic FAPT
3. EXECUTION OF
Reversing screws can be machined by selectively specifying either
“on the next element” or “on the last element”. If the rotating direction
of the blank is the same and the cutting direction is reversed in the
previous figure, screws are threaded reversely.
When chamfering was made by , the length of thread
can be calculated from the intersection of linear element
(d)Lead length, pitch, and number of thread
The lead is defined as the Z–axis direction length when a screw
returns to the original angle after turning once.
In case of a one–thread screw, the pitch coincides with the lead.
In case of a three–thread screw, 1/3 of lead corresponds to the pitch.
The lead of a taper screw is also calculated in the Z–axis direction.
(e) Depth of thread
Together with the prompt on the depth of thread DT, the following
soft keys are displayed on the screen:
ESCAPE BACK OUTER INNER SQUARE CURSOR CURSOR NEXT
PAGE THREAD THREAD THREAD " # PAGE
If one of the soft keys is pressed, the depth of thread DT is
automatically calculated. The calculation is defined as follows:
Pitch = LD (lead)/NT (number of threads)
OUTER THREAD: Pitch Constant (system parameter
No.174), initial value 0.7578
INNER THREAD: Pitch Constant (system parameter
No.125), initial value 0.6495
SQUARE THREAD: Pitch/(2 NT (number of threads))
If the value obtained by automatic calculation is unsatisfactory,
modify the data manually. For a trapezoidal thread, enter the data
manually. After the depth of thread (DT) has been automatically
calculated and specified, the cursor is repositioned to the first