HEIDENHAIN TNC 620 User Manual page 380

10
Programming: Miscellaneous Functions
10.4 Miscellaneous functions for path behavior
Feed rate for 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 so that the feed rate at the tool cutting edge remains
constant.
Caution: Danger to the workpiece and tool!
On very small outside corners the TNC may increase
the feed rate so much that the tool or workpiece may
be damaged. Avoid M109 with small outside corners.
Behavior at circular arcs with M110
The TNC keeps the feed rate constant for circular arcs at inside
contours only. Adjustment of the feed rate does not have any effect
when machining the outside contours of circular arcs.
If you define M109 or M110 before calling a
machining cycle with a number greater than 200,
the adjusted feed rate is also effective for circular
arcs within these machining cycles. The initial state
is restored after finishing or canceling a machining
cycle.
Effect
M109 and M110 become effective at the start of block. To cancel
M109 or M110, enter M111.
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HEIDENHAIN | TNC 620 | Conversational Programming User's Manual | 10/2015