HEIDENHAIN TNC 426 CB, Technical Manual

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6 – 206 HEIDENHAIN Technical Manual TNC 426, TNC 430
6.12.8 Tapping with Floating Tap Holder and Nominal Speed Output
For tapping with floating tap holder, the position control loop is open. M4030
is set during the tapping cycle. After the spindle is switched on with M03, this
is acknowledged with M4092. The nominal spindle speed must be reached
before infeed begins.
During switch-on, the spindle follows the ramp in MP3411.x. During switch-
off, it follows the ramp in MP3412.2:
7 7 7 7 In MP3412.2, enter a multiplier for MP3411 during tapping.
7 7 7 7 In MP3415.2, define the overshoot behavior of the spindle during tapping.
7 7 7 7 Acknowledge the output of the M functions. An NC stop cannot be
executed until a previous M function is acknowledged.
If the feed-rate and spindle ramps have differing gradients, the spindle follows
the slower ramp.
Example:
Speed s = 1000 [rpm] = 1.8 [V]
MP3411.x = 0.05 [V/ms]
In this example the spindle was braked 36 ms before reaching the hole depth.
Delay times permit an optimum adjustment of the floating tap holder. You can
delay the switch-off:
7 7 7 7 In MP7120.2 enter a spindle slow-down time.
The delay cannot last longer than 30 ms before reaching the hole depth.
Values above 30 ms are ignored. (See also diagram below.)
You can delay a subsequent spindle start with M04:
7 7 7 7 In MP7120.0 enter a dwell time. The ramp follows MP3412.2
You can delay restarting the infeed:
7 7 7 7 Change the programmed dwell time in the cycle.
The NC uses M05 to switch off the spindle. The switch-off ramp follows
MP3412.0. Then the spindle is switched back on with M03.
The feed rate override for tapping must be limited. Otherwise the floating tap
holder may be damaged:
7 7 7 7 Enter a limit in MP7110.x.
1.8 [V]
0.05 [V/ms]
------------------------------------ 36 ms =