HEIDENHAIN TNC 407 (280 580) ISO Programming - Manual (Page 233)

8-13
8 Cycles
TNC 426/TNC 425/TNC 415 B/TNC 407
POCKET MILLING (G75/G76)
Process
The rectangular pocket milling cycle is a roughing cycle, in which
• the tool penetrates the workpiece at the starting position (pocket center)
• the tool subsequently follows the programmed path at the specified feed
rate (see figure 8.10)
The cutter begins milling in the positive direction of the axis of the longer
side. The cutter always starts in the positive Y direction on square pock-
ets. At the end of the cycle, the tool is retracted to the starting position.
Required tool / limitations
The cycle requires a center-cut end mill (ISO 1641) or pilot drilling at the
pocket center. The pocket sides are parallel to the axes of the coordinate
system.
Direction of rotation for roughing-out
Clockwise: G75
Counterclockwise: G76
Input data
• SETUP CLEARANCE A
• MILLING DEPTH B
The algebraic sign determines the working direction (a negative value
means negative working direction).
• PECKING DEPTH C
• FEED RATE FOR PECKING:
Traversing speed of the tool during penetration.
• FIRST SIDE LENGTH D :
Pocket length, parallel to the first main axis of the machining plane.
• SECOND SIDE LENGTH E :
Pocket width
The signs of the side lengths are always positive.
• FEED RATE:
Traversing speed of the tool in the machining plane.
Calculations
The stepover factor k is calculated as follows:
k = K x R
where K is the overlap factor (preset by the machine manufacturer) and
R is the cutter radius.
Corner radius
The corner radius is determined by the radius of the milling tool.
Starting point
Before a cycle is called, the tool must be moved to the following starting
point with tool radius compensation G40:
• In the tool axis, to setup clearance above the workpiece surface.
• In the machining plane, to the pocket center.
Fig. 8.10: Tool path for roughing-out
Fig. 8.8: Infeeds and distances for the
POCKET MILLING cycle
Fig. 8.9: Side lengths of the pocket
8.2 Simple Fixed Cycles
A
B
C
E
D
G76
G75
F
k