Please Note While Programming - HEIDENHAIN TNC 620 User Manual

3
Fixed Cycles: Drilling
3.7 BACK BORING (Cycle 204)

Please note while programming:

Machine and TNC must be specially prepared by the
machine tool builder for use of this cycle.
This cycle is effective only for machines with servo-
controlled spindle.
Special boring bars for upward cutting are required
for this cycle.
Program a positioning block for the starting point
(hole center) in the working plane with radius
compensation R0.
After machining, the TNC positions the tool back at
the starting point of the machining plane. This way,
you can continue positioning incrementally.
The algebraic sign for the cycle parameter depth
determines the working direction. Note: A positive
sign bores in the direction of the positive spindle
axis.
The entered tool length is the total length to the
underside of the boring bar and not just to the tooth.
When calculating the starting point for boring, the
TNC considers the tooth length of the boring bar and
the thickness of the material.
If the functions M7 or M8 were active before calling
the cycle, the TNC will reconstruct this previous
state at the end of the cycle.
Danger of collision!
Check the position of the tool tip when you program
a spindle orientation to the angle that you enter in
Q336 (for example, in the Positioning with Manual
Data Input mode of operation). Set the angle so that
the tool tip is parallel to a coordinate axis. Select a
disengaging direction in which the tool moves away
from the edge of the hole.
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HEIDENHAIN | TNC 620 | User's manual for cycle programming | 9/2015