HEIDENHAIN TNC 640 (34059x-01) ISO programming User Manual
Page 347

HEIDENHAIN TNC 640
347
1
1
.4 Miscellaneous F
unctions f
o
r Rotary Ax
es
M128 with 3-D tool compensation
If you carry out a 3-D tool compensation with active M128 and active 
radius compensation G41/G42, the TNC will automatically position the 
rotary axes for certain machine geometrical configurations (Peripheral 
milling. 
Effect
M128
becomes effective at the start of block, M129 at the end of block.
M128
is also effective in the manual operating modes and remains
active even after a change of mode. The feed rate for the 
compensation movement will be effective until you program a new 
feed rate or until you cancel M128 with M129.
Enter M129 to cancel M128. The TNC also cancels M128 if you select a 
new program in a program run operating mode.
Example NC blocks
Feed rate of 1000 mm/min for compensation movements:
Inclined machining with noncontrolled rotary axes
If you have noncontrolled rotary axes (counting axes) on your machine, 
then in combination with M128 you can also perform inclined 
machining operations with these axes.
Proceed as follows:
1
Manually traverse the rotary axes to the desired positions. M128 
must not be active!
2
Activate M128: The TNC reads the actual values of all rotary axes 
present, calculates from this the new position of the tool center 
point, and updates the position display
3
The TNC performs the necessary compensating movement in the 
next positioning block
4
Carry out the machining operation
5
At the end of program, reset M128 with M129, and return the 
rotary axes to the initial positions
N50 G01 G41 X+0 Y+38.5 IB-15 F125 M128 F1000 *
As long as M128 is active, the TNC monitors the actual 
positions of the noncontrolled rotary axes. If the actual 
position deviates from the nominal position by a value 
greater than that defined by the machine manufacturer, 
the TNC outputs an error message and interrupts program 
run.
