Siemens SINUMERIK 840Di Function Manual page 1618

Detailed Description
2.1 Path feedrate F
At the end of the acceleration ramp, the position coupling between the spindle actual value
(spindle setpoint with SPCON on master spindle) and the axis setpoint is established. At this
moment, the position of the axis in relation to the zero mark of the spindle (including zero
mark offsets) is as if the axis had accelerated abruptly at the start of the block when the
thread start position (zero mark plus SF) was crossed. Compensation is made for the
following error of the axis.
Minimum spindle speed
In order to ensure smooth rotation at low speeds, the spindle speed is not permitted to fall
below a minimum level.
This speed can be set in setting data:
SD43210 SPIND_MIN_VELO_G25 (minimum spindle speed)
and for each gear stage with machine data:
MD35140 GEAR_STEP_MIN_VELO_LIMIT
(minimum speed for gear stage change).1
The minimum spindle speed can be changed in the part program with G25.
NC STOP, single block
NC STOP and single block (even at the block boundary) are only active after completion of
thread chaining. All subsequent G33 blocks and the first subsequent non G33 block are
traversed like a single block.
Premature abortion without destruction
Thread cutting can be aborted without destruction before the end point is reached. This can
be done by activating a retraction motion.
Thread cutting with ROT frame
With ROT frame and G33,G34,G35, alarm 10607 "Thread with frame not executable" is
activated if the rotation causes a change in the thread length and thus the lead. Rotation
around the thread axis is permissible.
Alarm 10607 "Thread with frame not executable" can be suppressed by setting bit 12 in
machine data:
MD11410 SUPPRESS_ALARM_MASK
if the ROT instruction is used specifically in the application.
All other frames are accepted by the NC without alarm. Attention is drawn to the lead-
changing effect of SCALE.
2-10
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
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