HEIDENHAIN TNC 407 (280 580) ISO Programming - Manual (Page 237)

8-17
8 Cycles
TNC 426/TNC 425/TNC 415 B/TNC 407
8.3 SL Cycles (Group I)
SL cycles are highly efficient cycles that allow machining of any contour.
These cycles have the following characteristics:
• A contour can be composed of several overlapping subcontours.
Islands or pockets can form a subcontour.
• The subcontours are defined in subprograms.
• The control automatically superimposes the subcontours and calculates
the points of intersection formed by overlapping.
The term SL is derived from the characteristic Subcontour List of Cycle
G37 CONTOUR GEOMETRY. Since this is purely a geometry cycle, no
cutting data or feed values are defined.
The machining data are specified in the following cycles:
• PILOT DRILLING (G56)
• ROUGH-OUT (G57)
• CONTOUR MILLING (G58/G59)
The SL cycles of group II offer further, contour-oriented machining
processes and are described later.
Each subprogram defines whether G41 or G42 radius compensation
applies. The sequence of points determines the direction of rotation in
which the contour is machined. The control infers from these data
whether the specific subprogram describes a pocket or an island:
• The control recognizes a pocket if the tool path lies inside the contour
• The control recognizes an island if the tool path lies outside the contour
• The machining of the SL contour is determined by MP 7420.
• It is a good idea to run a graphic simulation before executing a program to see whether the contours were
correctly defined.
• The memory capacity for programming an SL cycle is limited. For example, you can program 128 straight line
blocks in one SL cycle.
• All coordinate transformations are allowed in programming the subcontours.
• Any words starting with F or M in the subprograms for the subcontours are ignored.
For easier familiarization, the following examples begin with only the
rough-out cycle and then proceed progressively to the full range of
functions provided by this group of cycles.
Programming parallel axes
Machining operations can also be programmed in parallel axes as SL
cycles. (In this case, graphic simulation is not available.) The parallel axes
must lie in the machining plane.
Input data
Parallel axes are programmed in the first coordinate block (positioning
block, I,J,K block) of the first subprogram called in Cycle G37 CONTOUR
GEOMETRY. Coordinate axes entered subsequently will be ignored.