HEIDENHAIN TNC 320 User Manual page 200

Please note while programming:
The machine and TNC must be prepared for cylinder
surface interpolation by the machine tool builder. Refer to
your machine manual.
In the first NC block of the contour program, always
program both cylinder surface coordinates.
The memory capacity for programming an SL cycle is
limited. You can program up to 16384 contour elements in
one SL cycle.
The algebraic sign for the cycle parameter DEPTH
determines the working direction. If you program
DEPTH=0, the cycle will not be executed.
This cycle requires a center-cut end mill (ISO 1641).
The cylinder must be set up centered on the rotary table.
Set the reference point to the center of the rotary table.
The spindle axis must be perpendicular to the rotary table
axis when the cycle is called; switching of the kinematics
may be required. If this is not the case, the TNC will
generate an error message.
This cycle can also be used in a tilted working plane.
The set-up clearance must be greater than the tool radius.
The machining time can increase if the contour consists of
many non-tangential contour elements.
200 Fixed Cycles: Cylindrical Surface