HEIDENHAIN TNC 640 (34059x-05) Cycle programming - Manual (Page 164)

Fixed Cycles: Pocket Milling / Stud Milling / Slot Milling
5.7 CIRCULAR STUD (Cycle 257, DIN/ISO: G257)
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TNC 640 | User's Manual Cycle Programming | 1/2015
Please note while programming:
Pre-position the tool in the machining plane to
the starting position (stud center) with radius
compensation
R0.
The TNC automatically pre-positions the tool in the
tool axis. Note the
2nd set-up clearance Q204.
The algebraic sign for the cycle parameter DEPTH
determines the working direction. If you program
DEPTH=0, the cycle will not be executed.
At the end of the cycle, the TNC returns the tool to
the starting position.
The TNC reduces the infeed depth to the LCUTS tool
length defined in the tool table if the tool length is
shorter than the Q202 infeed depth programmed in
the cycle.
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 set-up clearance below
the workpiece surface!
Depending on the starting angle Q376, leave enough
room next to the stud for the approach motion. At
least tool diameter + 2 mm.
At the end, the TNC positions the tool back to the
set-up clearance, or to the 2nd set-up clearance
if one was programmed. This means that the end
position of the tool after the cycle differs from the
starting position.