HEIDENHAIN TNC 410 ISO Programming - Manual (Page 264)

238 8 Programming: Cycles
8.4 Cy
cles f
o
r Mil
ling P
o
c
k
e
ts, St
ud
s an
d Slo
ts
CIRCULAR POCKET MILLING (Cycle G77, G78)
1 The tool penetrates the workpiece at the starting position (pocket
center) and advances to the first plunging depth.
2 The tool subsequently follows a spiral path at the feed rate F - see
figure at right. For calculating the stepover factor k, see Cycle 4
POCKET MILLING.
see “POCKET MILLING (Cycles G75, G76),”
page 232
3 This process is repeated until the depth is reached.
4 At the end of the cycle, the TNC retracts the tool to the starting
position.
Direction of rotation during rough-out
n In clockwise direction: G77 (DR-)
n
In counterclockwise direction: G78 (DR+)
U U U U Set-up clearance 1 (incremental value): Distance
between tool tip (at starting position) and workpiece
surface
U U U U Milling depth 2 : Distance between workpiece
surface and bottom of pocket
U U U U Plunging depth 3 (incremental value): Infeed per cut
The TNC will go to depth in one movement if:
n the plunging depth is equal to the depth
n the plunging depth is greater than the depth
X
Y
X
Z
11
12
13
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.