HEIDENHAIN TNC 640 (34059x-05) ISO programming - Manual (Page 457)

Basic functions (Option 50) 14.2
14
TNC 640 | User's ManualDIN/ISO Programming | 1/2015
457
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
%LT 200 G71 *
N40 G00 G40 G90 X+102 Z+2
Movement at rapid traverse
...
N30 G01 X+87 F200 *
Movement at a feed rate of 200 mm/min
N40 M136 * Feed rate in millimeters per revolution
N50 G01 X+154 F0.2 * Movement at a feed rate of 0.2 mm/rev.
...