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Feed rate, Tool call – HEIDENHAIN TNC 640 (34059x-04) ISO programming User Manual

Page 433

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Basis Functions (Software Option 50) 14.2

14

TNC 640 | User's Manual for DIN/ISO Programming | 3/2014

433

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.

...

Tool call

Just as in Milling mode, turning tools are called with the

TOOL

CALL function. You merely have to enter the tool number or tool
name in the

TOOL CALL block.

You can call and insert a turning tool both in Milling

mode and in Turning mode.

NC syntax

N40 FUNCTION MODE TURN

Turning mode selection

N50 T301

Tool call