8-31
8
Cycles
TNC 426/TNC 425/TNC 415 B/TNC 407
8.4 SL Cycles (Group II)
The SL cycles of group II allow
contour-oriented machining of complex
contours and achieve a particularly high degree of surface finish.
These cycles differ from those of group I in the following ways:
• Before the cycle starts, the TNC automatically positions the tool to the
setup clearance.
• 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 for
the outermost pass in Cycles G123 and G124).
• The contour is approached in a tangential arc for side finishing.
• For floor finishing, the tool again approaches the workpiece in a tangen-
tial arc (for tool 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.
• MP 7420 is replaced by DIRECTION OF ROTATION Q9.
The machining data (such as milling depth, finishing allowance and setup
clearance) are entered as CONTOUR DATA in Cycle G120.
There are four cycles for contour-oriented machining:
• PILOT DRILLING (G121)
• ROUGH-OUT (G122)
• FLOOR FINISHING (G123)
• SIDE FINISHING (G124)
