8-19
8
Cycles
TNC 426/TNC 425/TNC 415 B/TNC 407
Fig. 8.16:
Cutter path for roughing-out
Fig. 8.15:
Infeeds and distances of the
ROUGH-OUT cycle
A
B
C
D
D
α
ROUGH-OUT (G57)
The ROUGH-OUT cycle specifies cutting path and partitioning.
Sequence
• The control positions the tool in the tool axis over the first infeed point,
taking the finishing allowance into account.
• The tool then penetrates the workpiece at the programmed feed rate
for pecking.
Milling the contour:
• The tool mills the first subcontour at the specified feed rate, taking the
finishing allowance into account.
• As soon as the tool returns to the infeed point, it is advanced to the
next pecking depth.
This process is repeated until the programmed milling depth is reached.
• Further subcontours are milled in the same manner.
Roughing-out pockets:
• After milling the contour the pocket is roughed-out. The stepover is
defined by the tool radius.
Islands are jumped over.
• If required, pockets can be cleared with several downfeeds.
• At the end of the cycle, the tool is retracted to the setup clearance.
Required tool
The cycle requires a center-cut end mill (ISO 1641) if the pocket is not
separately pilot drilled or if the tool must repeatedly jump over contours.
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
• FINISHING ALLOWANCE
D
:
Allowance in the machining plane (positive value)
• ROUGH-OUT ANGLE
α
:
Feed direction for roughing-out.
The rough-out angle is relative to the angle reference axis and can be
set, so that the resulting cuts are as long as possible with few cutting
movements.
• FEED RATE:
Traversing speed of the tool in the machining plane
The machine parameters determine whether
• the contour is milled first and then surface machined, or vice versa
• the contour is milled conventionally or by climb cutting
• all pockets are roughed-out first and then contour-milled over all
infeeds, or whether
• contour milling and roughing-out are performed mutually for each
infeed
