Pilot Drilling (Cycle 15) - HEIDENHAIN TNC 370 User Manual

8 Cycles
8.5 SL Cycles
PILOT DRILLING (Cycle 15)
Process
Pilot drilling of holes for cutter infeed at the starting points of the subcon-
tours. With SL contours that consist of several overlapping surfaces, the
cutter infeed point is the starting point of the first subcontour:
l
The tool is positioned above the first infeed point.
l
The subsequent drilling sequence is identical to that of Cycle 1
PECKING.
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The tool is then positioned above the next infeed point, and the
drilling process is repeated.
Input data
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SET-UP CLEARANCE (incremental value):
Distance between tool tip (starting position) and workpiece surface.
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TOTAL HOLE DEPTH (incremental value):
Y
-4
-x
Distance between workpiece surface and bottom of hole (tip of drill
Fig. 8.54:
Example of cutter infeed points for
taper).
PECKING
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PECKING DEPTH (incremental value):
lnfeed per cut. The TNC moves in one operation to the TOTAL HOLE
DEPTH if:
.-
- PECKING DEPTH and TOTAL HOLE DEPTH are identical
YA
- the PECKING DEPTH is greater than the TOTAL HOLE DEPTH.
The TOTAL HOLE DEPTH does not have to be a multiple of the
PECKING DEPTH.
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FEED RATE F:
Traversing speed of the tool during drilling.
l
FINISHING ALLOWANCE
Allowed material for the drilling operation (see Fig. 8.55).
The sum of the tool radius and finishing allowance should be the
same for pilot drilling and roughing out.
I 4
Fig. 8.55: Finishing allowance
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8-50
TNC 370