Siemens SINUMERIK 840C User Manual
Page 406
12.93
6 NC Machine Data (NC MD), NC Setting Data (NC SD)
6.12.1 NC setting data (NC SD)
General setting data
Dry run feedrate
0
Default value
Lower input limit
Upper input limit
Units
0
0
1072 0000
9999 9999 (as from
SW 5)
1 000 units/min
Active on
–
If ”Dry run feedrate” is selected on the control, the tool path feedrate selected is the dry run
feedrate (mm/min (G94)) and not the programmed feedrate.
Dyn. smoothing time thread cutting
1
Default value
Lower input limit
Upper input limit
Units
0
0
5
2
n
-1 ×IPO cycle
Active on
–
Programming smoothing exponent via G92 T..
This function is used to protect the drive when cutting threads and to obtain a better speed
stability.
The feed ramp-up time until synchronization with the working spindle already running is
reached can be programmed using the command G92 T.. . The feed ramp-up time should be
matched to the running path available:
•
short run-in path, short ramp-up time, low T value
•
long run-in path, long ramp-up time, high T value
The programmed ramp-up time also acts as the smoothing time, i.e. the actual spindle speed
is averaged via this value an even feedrate is thus obtained.
The smoothing and feed ramp-up time depends on
•
the programmed value T..
•
the interpolation cycle which is set in NC MD 155; this machine data should only be
changed by a properly trained specialist.
The value T.. must be an integer. Possible values are 0...5. The following table shows which T
value must be programmed for a set interpolation cycle in order to obtain the required feed
ramp-up time:
Thread cutting with constant lead (G33)
Thread cutting with linear increasing lead (G34)
Thread cutting with linear decreasing lead (G35)
Program syntax:
N.. G33
N.. G34
N.. G35
The action of G functions G33, G34, G35 are modal.
The programmed feedrate F has no meaning but remains modal, i.e. the feedrate is derived
internally from the actual speed value of the leading spindle.
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Siemens AG 1992 All Rights Reserved 6FC5197- AA50
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SINUMERIK 840C (IA)