
B-63783EN-1/01 6.INTERPOLATION FUNCTION
- 559 -
6.4 THREADING
6.4.1 Threading
Overview
A thread can be cut by moving a tool in synchronization with the rotating
spindle.
The spindle speed is sequentially read from the position coder mounted
on the spindle and is converted into a feedrate of cutting feed per minute,
according to which the tool is moved.
Fig. 6.4 (a) Thread Forms
Generally, threading consists of a range of processes from roughing to
finishing, with a single path being repeatedly followed to form a single
thread.
Each threading sequence starts after a one-rotation signal is detected
from the position coder mounted on the spindle. Therefore, threading
can be repeated with the same cutting start point on the circumference of
the workpiece and the same tool path. The spindle speed must be kept
constant from roughing through finishing. Any variation in the spindle
speed may result in a slight deviation of the thread.
Signal
Threading in progress signal THRD<F001#6>
[Classification] Output signal
[Function] Notifies that threading is in progress.
[Output condition] The signal is held to 1 when:
- The CNC is in threading mode.
- A threading cycle for turning is in progress.
The signal is held to 0 when the CNC is not in threading mode and when
a threading cycle is not in progress.
L
Straight thread
L
L
Tapered thread
Stoke thread
L : Lead