HEIDENHAIN TNC 640 User Manual page 287

Fixed Cycles: Contour Pocket with Contour Formula | SL cycles with simple contour formula
Properties of the subcontours
Do not program a radius compensation.
The TNC ignores feed rates F and miscellaneous functions M.
Coordinate transformations are allowed. If they are programmed
within the subcontour they are also effective in the following
subprograms, but they need not be reset after the cycle call.
Although the subprograms can contain coordinates in the
spindle axis, such coordinates are ignored.
The working plane is defined in the first coordinate block of the
subprogram.
Characteristics of the fixed cycles
The TNC automatically positions the tool to the set-up clearance
before a cycle.
Each level of infeed depth is milled without interruptions since
the cutter traverses around islands instead of over them.
The radius of "inside corners" can be programmed—the tool
keeps moving to prevent surface blemishes at inside corners
(this applies to the outermost pass in the Rough-out and Side
Finishing cycles).
The contour is approached in a tangential arc for side finishing.
For floor finishing, the tool again approaches the workpiece on a
tangential arc (for spindle axis Z, for example, the arc may be in
the Z/X plane).
The contour is machined throughout in either climb or up-cut
milling.
The machining data (such as milling depth, finishing allowance and
set-up clearance) are entered as CONTOUR DATA in Cycle 20.
HEIDENHAIN | User's manual for cycle programming | 10/2017
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