HEIDENHAIN TNC 640 (34059x-01) - Manual (Page 419)

HEIDENHAIN TNC 640 419
13.2 Basis F
unctions (Sof
tw
ar
e Option 50)
Feed rate
With turning, feed rates or 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
Z
X
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.
...