7 Programming: Miscellaneous functions
142
Feed rate at circular arcs: M109/M110/M111
Standard behavior
The TNC applies the programmed feed rate to the path of the tool
center.
Behavior at circular arcs with M109
The TNC adjusts the feed rate for circular arcs at inside and outside
contours such that the feed rate at the tool cutting edge remains
constant.
Behavior at circular arcs with M110
The TNC keeps the feed rate constant for circular arcs at inside
contours only. At outside contours, the feed rate is not adjusted.
M110 is also effective for the inside machining of circular
arcs using contour cycles.
Effect
M109 and M110 become effective at the start of the block.
To cancel M109 or M110, enter M111.
Calculating the radius-compensated path in
advance (LOOK AHEAD): M120
Standard behavior
If the tool radius is larger than the contour step that is to be
machined with radius compensation, the TNC interrupts program
run and generates an error message. Although you can use M97 to
inhibit the error message (see “Machining small contour steps:
M97”), this will result in dwell marks and will also move the corner.
If the programmed contour contains undercut features, the tool
may damage the contour. —See figure at right.
Behavior with M120
The TNC checks radius-compensated paths for contour undercuts
and tool path intersections, and calculates the tool path in advance
from the current block. Areas of the contour that might be damaged
by the tool, are not machined (dark areas in figure at right). You can
also use M120 to calculate the radius compensation for digitized
data or data created on an external programming system. This
means that deviations from the theoretical tool radius can be
compensated.
Use LA (
L
ook
A
head) behind M120 to define the number of blocks
(maximum: 99) that you want the TNC to calculate in advance. Note
that the larger the number of blocks you choose, the higher the
block processing time will be.
X
Y
7.4 Miscellaneous F
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Summary of Contents for TNC 426 B
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Page 83: ...Programming Tools 5 Fkap5 pm6 30 06 2006 07 03 67 www EngineeringBooksPdf com ...
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Page 166: ...Programming Cycles 8 kkap8 pm6 30 06 2006 07 03 151 www EngineeringBooksPdf com ...
Page 253: ...kkap8 pm6 30 06 2006 07 04 238 www EngineeringBooksPdf com ...
Page 265: ...LKAP9 PM6 30 06 2006 07 04 250 www EngineeringBooksPdf com ...
Page 266: ...Programming Q Parameters 10 MKAP10 PM6 30 06 2006 07 04 251 www EngineeringBooksPdf com ...
Page 297: ...MKAP10 PM6 30 06 2006 07 04 282 www EngineeringBooksPdf com ...
Page 298: ...Test Run and Program Run 11 NKAP11 PM6 30 06 2006 07 04 283 www EngineeringBooksPdf com ...
Page 312: ...MOD Functions 12 Okap12 pm6 30 06 2006 07 04 297 www EngineeringBooksPdf com ...
Page 332: ...Tables and Overviews 13 Pkap13 pm6 30 06 2006 07 04 317 www EngineeringBooksPdf com ...