HEIDENHAIN TNC 410 ISO Programming - Manual (Page 288)

262 8 Programming: Cycles
8.6 SL Cy
cles Gr
ou
p I
PILOT DRILLING (Cycle G56)
Process
Same as Cycle G83 Pecking; see “Cycles for Drilling, Tapping and
Thread Milling,” page 183.
Application
Cycle G56 is for PILOT DRILLING of the cutter infeed points. It
accounts for the finishing allowance. The cutter infeed points also
serve as starting points for roughing.
U U U U Set-up clearance 1 (incremental value): Distance
between tool tip (at starting position) and workpiece
surface
U U U U Total hole depth 2 (incremental value): Distance
between workpiece surface and bottom of hole (tip of
drill taper)
U U U U Plunging depth 3 (incremental value): Infeed per cut
The total hole depth does not have to be a multiple of
the plunging depth. The tool will drill to the total hole
depth in one movement if:
n the plunging depth is equal to the depth
n the plunging depth is greater than the total hole
depth
U U U U Feed rate for plunging : Traversing speed in mm/min
for drilling
U U U U Finishing allowance: Allowance in the machining
plane
Example: NC blocks
N54 G56 P01 2 P02 -15 P03 5 P04 250
P05 +0.5*
X
Y
X
Z
11
2
3
Before programming, note the following:
Program a positioning block for the starting point in the
tool axis (set-up clearance above the workpiece surface).