Pocket Milling (Cycle 4) - HEIDENHAIN TNC 426 B User Manual

POCKET MILLING (Cycle 4)

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.
Before programming, note the following:
Program a positioning block for the starting point (pocket
center) in the working plane with RADIUS
COMPENSATION R0.
Program a positioning block for the starting point in the
tool axis (set-up clearance above the workpiece surface).
The algebraic sign for the depth parameter determines
the working direction.
This cycle requires a center-cut end mill (ISO 1641), or
pilot drilling at the pocket center.
The following condition must be met for the second line
length:
2nd side length greater than [(2 x rounding-off radius) +
stepover factor k].
Setup clearance
between tool tip (at starting position) and workpiece
surface
Milling depth
workpiece surface and bottom of pocket
Plunging depth
Infeed per cut. The tool will advance to the depth in
one movement if:
the plunging depth equals the depth
the plunging depth is greater than the depth
Feed rate for plunging: Traversing speed of the tool
during penetration
1st side length
axis of the working plane
2nd side length
Feed rate F: Traversing speed of the tool in the
working plane
HEIDENHAIN TNC 426 B, TNC 430
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(incremental value): Distance
(incremental value): Distance between
(incremental value):
: Pocket length, parallel to the main
: Pocket width
Z
Example NC blocks:
27 Y L DEF 4.0 PO KET MILLING
28 Y L DEF 4.1 SET UP
29 Y L DEF 4.2 DEPTH -20
30 Y L DEF 4.3 PLNGNG
31 Y L DEF 4.4 X80
32 Y L DEF 4.5 Y60
33 Y L DEF 4.6 F275 DR+ RADIUS 5
X
2
5 F100
169