HEIDENHAIN TNC 320 (340 55x-04) Cycle programming - Manual (Page 142)

142 Fixed Cycles: Pocket Milling / Stud Milling / Slot Milling
5.5 CIR
C
ULAR SL
O
T
(Cy
c
le 254, DIN/ISO: G254)
Please note while programming:
With an inactive tool table you must always plunge
vertically (Q366=0) because you cannot define a plunging
angle.
Pre-position the tool in the machining plane with radius
compensation R0. Define Parameter Q367 (Reference for
slot position)
appropriately.
The TNC automatically pre-positions the tool in the tool
axis. Note Parameter Q204 (2nd setup clearance).
At the end of the cycle the TNC returns the tool to the
starting point (center of the circular arc) in the working
plane. Exception: if you define a slot position not equal to
0, then the TNC only positions the tool in the tool axis to
the 2nd setup clearance. In these cases, always program
absolute traverse movements after the cycle call.
The algebraic sign for the cycle parameter DEPTH
determines the working direction. If you program DEPTH
= 0, the cycle will not be executed.
If the slot width is greater than twice the tool diameter, the
TNC roughs the slot correspondingly from inside out. You
can therefore mill any slots with small tools, too.
The slot position 0 is not allowed if you use Cycle 254
Circular Slot in combination with Cycle 221.
Danger of collision!
Use the machine parameter displayDepthErr to define
whether, if a positive depth is entered, the TNC should
output an error message (on) or not (off).
Keep in mind that the TNC reverses the calculation for pre-
positioning when a positive depth is entered. This
means that the tool moves at rapid traverse in the tool axis
to setup clearance below the workpiece surface!
If you call the cycle with machining operation 2 (only
finishing), then the TNC positions the tool to the first
plunging depth at rapid traverse!