HEIDENHAIN TNC 620 (340 56x-01) - Manual (Page 248)

248
8.2 Cy
cles f
o
r Dr
illing, T
apping and Thr
ead Milling
 Retraction rate for chip breaking Q256: The TNC
multiplies the pitch Q239 by the programmed value
and retracts the tool by the calculated value during
chip breaking. If you enter Q256 = 0, the TNC retracts
the tool completely from the hole (to the set-up
clearance) for chip release.
 Angle for spindle orientation Q336 (absolute
value): Angle at which the TNC positions the tool
before machining the thread. This allows you to
regroove the thread, if required.
 RPM factor for retraction Q403: Factor by which
the TNC increases the spindle speed—and therefore
also the retraction feed rate—when retracting from
the drill hole. Input range: 0.0001 to 10
Retracting after a program interruption
If you interrupt program run during thread cutting with the machine
stop button, the TNC will display the soft key MANUAL OPERATION.
If you press the MANUAL OPERATION key, you can retract the tool
under program control. Simply press the positive axis direction button
of the active spindle axis.
Example: NC blocks
26 CYCL DEF 209 TAPPING W/ CHIP BRKG
Q200=2 ;SET-UP CLEARANCE
Q201=-20 ;DEPTH
Q239=+1 ;PITCH
Q203=+25 ;SURFACE COORDINATE
Q204=50 ;2ND SET-UP CLEARANCE
Q257=5 ;DEPTH FOR CHIP BRKNG
Q256=+25 ;DIST. FOR CHIP BRKNG
Q336=50 ;ANGLE OF SPINDLE
Q403=1.5 ;RPM FACTOR
When using the rpm factor for retraction, ensure that a
gear range change is excluded. If necessary, the TNC
limits the speed so that retraction is executed in the
currently active gear range.