HEIDENHAIN TNC 640 (34059x-04) Cycle programming - Manual (Page 161)

CIRCULAR STUD (Cycle 257, DIN/ISO: G257) 5.7
5
TNC 640 | User's Manual Cycle Programming | 3/2014
161
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!
Leave enough room next to the stud for the approach
motion. Minimum: 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.