HEIDENHAIN TNC 320 (77185x-01) ISO programming - Manual (Page 370)

Programming: Multiple Axis Machining
12.3 Miscellaneous functions for rotary axes
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TNC 320 | User's Manual for DIN/ISO Programming | 3/2014
12.3 Miscellaneous functions for rotary
axes
Feed rate in mm/min on rotary axes A, B, C:
M116 (software option 1)
Standard behavior
The TNC interprets the programmed feed rate of a rotary axis in
degrees/min (in mm programs and also in inch programs). The feed
rate therefore depends on the distance from the tool center to the
center of axis rotation.
The larger this distance becomes, the greater the contouring feed
rate.
Feed rate in mm/min on rotary axes with M116
The machine geometry must be specified by the
machine tool builder in the description of kinematics.
M116 works only on rotary tables. M116 cannot be
used with swivel heads. If your machine is equipped
with a table/head combination, the TNC ignores the
swivel-head rotary axes.
M116 is also effective in an active tilted working
plane and in combination with M128 if you used the
M138 function to select rotary axes, see "Selecting
tilting axes: M138", page 373. Then
M116 affects
only those rotary axes that were not selected with
M138.
The TNC interprets the programmed feed rate of a rotary axis in
degrees/min (or 1/10 inch/min). In this case, the TNC calculates the
feed for the block at the start of each block. With a rotary axis, the
feed rate is not changed during execution of the block even if the
tool moves toward the center of the rotary axis.
Effect
M116 is effective in the working plane. To reset M116, enter M117.
M116 is also canceled at the end of the program.
M116 becomes effective at the start of block.