HEIDENHAIN NC 124 - Manual (Page 79)

7 Drilling, Milling Cycles and Hole Patterns in Programs
TNC 124 79
PECKING
If you program Cycle 1.0 PECKING, the TNC drills to the pro-
grammed hole depth in several infeeds.
Process
The pecking cycle is illustrated in Fig. 7.2 and Fig. 7.3.
I
:
The TNC pre-positions the tool at setup clearance above the
workpiece surface.
II
:
The tool drills to the first pecking depth at the programmed ma-
chining feed rate F. After reaching the first pecking depth, the tool
retracts at rapid traverse (F MAX) to setup clearance .
III
:
The TNC pre-positions the tool at rapid traverse to the first infeed
depth , minus the advanced stop distance . The tool then
advances with another infeed .
IV
:
The TNC retracts the tool again and repeats the drilling process
(drilling/retracting) until the programmed hole depth is reached.
After a dwell time at the hole bottom, the tool is retracted to clear-
ance height at rapid traverse (F MAX) for chip breaking.
Advanced stop distance
The advanced stop distance for the drilling operation is auto-
matically calculated by the TNC:
Hole depth up to 30 mm: = 0.6 mm
Hole depth between 30 mm and 350 mm: = 0.02 • hole depth
Hole depth exceeding 350 mm: = 7 mm
Input data for Cycle 1.0 PECKING
• Clearance height - HEIGHT
Position in the tool axis at which the TNC can move the tool in
the working plane without damaging the workpiece.
• Setup clearance - DIST
The TNC advances the tool from clearance height to setup
clearance at rapid traverse.
• Workpiece surface - SURF
Absolute coordinate of the workpiece surface.
• Hole depth - DEPTH
Distance between workpiece surface and bottom of hole (tip of
drill taper).
• Pecking depth - PECKG
Infeed per cut.
• Dwell time - DWELL in [s]
Amount of time the tool remains at the hole depth for cutting
free the drill taper.
• Feed rate - F in [mm/min]
Traversing speed of the tool while drilling.
Hole depth and infeed depth
The infeed depth does not have to be a multiple of the hole depth.
If the infeed depth is programmed greater than the hole depth, or
equals the hole depth, the tool will drill to the programmed hole
depth in one operation.
Drilling Cycles in Programs
I
A
A
C
II
III IV
A
t
B
A
C
C
Fig. 7.3: Steps III and IV in Cycle 1.0
PECKING
Fig. 7.2: Steps I and II in Cycle
1.0 PECKING
A
A
C
C
C t
B
t
t
B
C
A
t
t
t