HEIDENHAIN TNC 640 (34059x-04) Cycle programming - Manual (Page 344)

Cycles: Turning
13.15 TURN CONTOUR FACE
(Cycle 820, DIN/ISO: G820)
13
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TNC 640 | User's Manual Cycle Programming | 3/2014
Finishing cycle run
If the Z coordinate of the starting point is less than the contour
starting point, the TNC positions the tool in the Z coordinate to set-
up clearance and begins the cycle there.
1 The TNC runs the infeed motion at rapid traverse.
2 The TNC finishes the finished part contour (contour starting
point to contour end point) at the defined feed rate
Q505.
3 The TNC returns the tool to set-up clearance at the defined feed
rate.
4 The TNC positions the tool back at rapid traverse to the cycle
starting point.
Please note while programming:
The cutting limit defines the contour range to be
machined. The approach and departure paths can
exceed the cutting limits.
The tool position before the cycle call influences the
execution of the cutting limit. The TNC 640 machines
the area to the right or to the left of the cutting
limit, depending on which side the tool has been
positioned before the cycle is called.
Program a positioning block to a safe position with
radius compensation
R0 before the cycle call.
The tool position at cycle call (cycle starting point)
affects the area to be machined.
The TNC takes the cutting geometry of the tool into
account to prevent damage to contour elements.
If complete machining with the active tool is not
possible, a warning is output by the TNC.
Before calling the cycle you must program the cycle
14 CONTOUR to define the subprogram number.
Also refer to the fundamentals of turning cycles (see
page 307).
When you use local QL Q parameters in a contour
subprogram you must also assign or calculate these
in the contour subprogram.