Pocket milling (cycles g75, g76) – HEIDENHAIN iTNC 530 (340 420) ISO programming User Manual
Page 271

HEIDENHAIN iTNC 530
271
8.4 Cy
cles f
o
r Milling P
o
c
k
ets, St
uds and Slots
POCKET MILLING (Cycles G75, G76)
1
The tool penetrates the workpiece at the starting position (pocket
center) and advances to the first plunging depth.
2
The cutter begins milling in the positive axis direction of the longer
side (on square pockets, always starting in the positive Y direction)
and then roughs out the pocket from the inside out.
3
This process (1 to 2) is repeated until the depth is reached.
4
At the end of the cycle, the TNC retracts the tool to the starting
position.
Example: NC blocks
N27 G75 P01 2 P02 -20 P03 5 P04 100
P05 X+80 P06 Y+40 P07 275 P08 5 *
...
N35 G76 P01 2 P02 -20 P03 5 P04 100
P05 X+80 P06 Y+40 P07 275 P08 5 *
X
Z
11
12
13
14
15
Before programming, note the following:
This cycle requires a center-cut end mill (ISO 1641), or pilot
drilling at the pocket center.
Pre-position over the pocket center with radius
compensation G40.
Program a positioning block for the starting point in the
tool axis (set-up clearance above the workpiece surface).
The algebraic sign for the cycle parameter DEPTH
determines the working direction. If you program
DEPTH = 0, the cycle will not be executed.
The following prerequisite applies for the 2nd side length:
2nd side length greater than [(2 x rounding radius) +
stepover factor k].