HEIDENHAIN TNC 640 (34059x-05) - Manual (Page 493)

Basic functions (Option 50) 14.2
14
TNC 640 | User's Manual
HEIDENHAIN Conversational Programming | 1/2015
493
Feed rate
With turning, feed rates are often specified in millimeters per
revolution. The TNC moves the tool according to a defined value for
each spindle revolution. The resulting contouring feed rate is thus
dependent on the speed of the turning spindle. With high speeds
the TNC increases the feed rate and with low speeds reduces
the feed rate. With uniform cutting depth you can machine with
constant cutting force to achieve a constant cut thickness.
The programmed feed rate on a TNC is by default always
interpreted in millimeters per minute (mm/min). If you wish to
define feed rate in millimeters per revolution (mm/rev.), you must
program
M136. The TNC then interprets all subsequent feed rate
specifications in mm/rev. until M136 is canceled.
M136 is effective modally at the beginning of the block and can be
canceled with
M137.
NC syntax
10 L X+102 Z+2 R0 FMAX
Movement at rapid traverse
...
15 L Z-10 F200
Movement at a feed rate of 200 mm/min
...
19 M136
Feed rate in millimeters per revolution
20 L X+154 F0.2
Movement at a feed rate of 0.2 mm/rev.
...