HEIDENHAIN TNC 620 User Manual page 107

Fixed Cycles: Drilling | SINGLE-LIP DEEP-HOLE DRILLING (Cycle 241, DIN/ISO: G241, software option 19)
Chip breaking
The point at which the TNC breaks the chip is also decisive when
working with extra-long tools. The retraction position with chip
breaking does not have to be at the position at which drilling is
started. A defined position for chip breakage can ensure that the
drill tool remains in the guide.
STARTING POINT Q379=0
Chip breaking is performed at SET-UP CLEARANCE Q200 above
the SURFACE COORDINATE Q203.
STARTING POINT Q379>0
Chip breaking is performed at a specific value above the
deepened starting point Q379. This value is calculated as
follows: 0.8 x Q379 If the result of this calculation is greater
than Q200 the value is always Q200.
Example:
SURFACE COORDINATE Q203 =0
SET-UP CLEARANCEQ200 =2
STARTING POINT Q379 =2
The position for chip breaking is calculated as follows:
0.8 x Q379=0.8*2=1.6; the position for chip breaking is 1.6 mm/
inch above the deepened starting point. Thus if the deepened
starting point is at -2 the TNC traverses for chip breaking to
-0.4 mm.
The following table shows various examples for calculating the
position for chip breaking (retraction position):
HEIDENHAIN | TNC 620 | User's manual for cycle programming | 10/2017
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