Spindle Override Change While Threading - Fagor CNC 8060 Installation Manual

2.5.12
2.
CNC 8060
CNC 8065
(R : 1709)
EF
·168·

Spindle override change while threading.

THREADOVR
Maximum variation allowed for the override while threading.
Parameter valid for spindles.
Parameter valid for analog drive, Sercos and simulated.
Possible values: from 0 to 100%.
Default value: 0 (The override cannot be changed).
Associated variable: (V.)[ch].MPA.THREADOVR.xn
If this parameter is set with a value other than ·0·, it is possible to change the spindle override
during electronic threading (G33) and in the threading canned cycles of the ·T· model (G86,
G87 and their equivalent of the cycle editor).
The parameter sets the maximum spindle override variation possible, both to increase it and
to reduce it. For example, if set to ·30·, the override may be varied between 80% and 130%.
The limits set by machine parameters MINOVR and MAXOVR can never be exceeded.
In order to avoid damaging the thread when varying the spindle override, you should use
a feed-forward value close to 100% on the axes involved in threading so the following error
is as small as possible. The CNC allows modifying the spindle override while threading if
it detects that the feed forward (parameter FFWTYPE) is not active in a gear of the axes
involved or if the active feed forward is lower than 90% Feed forward is defined with
parameter FFGAIN and may be modified from the PLC using variables.
Threading canned cycles of the ·T· model. Considerations related to changing the
override value.
• In threading cycles, it is possible to change the spindle speed during the threading
passes, except in those done all the way to the final depth of the thread (one or two final
passes) which are done at the override value active at the beginning of the pass.
• Even if the override is changed, the CNC respects the pitch and entry of the thread.
• It is recommended not to change the override on threads with flank infeed.
Electronic threading G33. Considerations related to changing the override value.
• If more than one G33 have been programmed for the same thread, all the threading
operations must start at the same speed; otherwise, the entry point (start) to the thread
will not be the same in all the threads. The CNC permits changing the spindle override
during the thread cutting pass.
• If more than one G33 have been programmed for a multi-start (multi-entry) thread, all
the threading operations must start at the same speed; otherwise, the angle between the
starts (entry points) to the thread will not be the same as the one programmed. The CNC
permits changing the spindle override during the thread cutting pass.
OVRFILTER
Time to make the override change effective.
Parameter valid for spindles.
Parameter valid for analog drive, Sercos and simulated.
Possible values: From 0 to 1000000 ms.
Default value: 0.
Associated variable: (V.)[ch].MPA.OVRFILTER.xn
The CNC takes this parameter into account only if THREADOVR other than 0 (zero).
This parameter acts as a filter to make the override change effective The override change
is applied progressively during the indicated period of time.
I n s ta ll a t io n ma n u a l.