Programming and Operating Manual (Milling)
208 6FC5398-4DP10-0BA1, 01/2014
● Retraction motion along a circle path in the opposite direction of rotation G2/G3 at the reduced feedrate FFR
● Retraction to the retraction plane along the applicate using G0
Sequence for internal thread
Position reached prior to cycle start:
The starting position is any position from which the center point of the thread at the height of the retraction plane can be
reached without collision.
The cycle creates the following sequence of motions:
● Positioning on the center point using G0 at the height of the retraction plane in the applicate of the current plane
● Infeed to the reference plane brought forward by the safety clearance for swarf removal, using G0
● Approach to an approach circle calculated internally in the cycle using G1 and the reduced feedrate FFR
● Approach motion to the thread diameter along a circle path according to the direction G2/G3 programmed under CDIR
● Thread milling along a helix path using G2/G3 and the feedrate value FFR
● Retraction motion along a circle path in the same direction of rotation at the reduced feedrate FFR
● Retraction to the center point of the thread using G0
● Retraction to the retraction plane along the applicate using G0
Thread from bottom to top
For technological reasons, it can also be reasonable to machine a thread from bottom to top. In this case, the retraction
plane RTP will be behind the thread depth DP.
This machining is possible, but the depth specifications must be programmed as absolute values and the retraction plane
must be approached before calling the cycle or a position after the retraction plane must be approached.
Programming example (thread from bottom to top)
A thread with a pitch of 3 mm is to start from -20 and to be milled to 0. The retraction plane is at 8.
N10 G17 X100 Y100 S300 M3 T1 D1 F1000
N30 CYCLE90 (8, -20, 0, -60, 0, 46, 40, 3, 800, 3, 0, 50,
The hole must have a depth of at least -21.5 (half pitch in excess).
Overshooting in the direction of the thread length
For thread milling, the travel-in and travel-out movements occur along all three axes concerned. This means that the travel-
out movement includes a further step in the vertical axis, beyond the programmed thread depth.
The overshoot is calculated as follows:
∆z: Overshoot, internal
p: Pitch
WR: Tool radius
DIATH: External diameter of the thread
RDIFF: Radius difference for travel-out circle
For internal threads, RDIFF = DIATH/2 - WR; for external threads, RDIFF = DIATH/2 + WR.
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