HEIDENHAIN TNC 640 (34059x-01) Cycle programming - Manual (Page 286)

286 Cycles: Turning
13.4 F
u
ndamentals of T
u
rn
ing Cy
cles
13.4 Fundamentals of Turning
Cycles
The pre-positioning of the tool decisively affects the workspace of the
cycle and thus the machining time. During roughing, the starting point
for cycles corresponds to the tool position when a cycle is called.
When calculating the area to be machined, the TNC takes into account
the starting point and the end point defined in the cycle or contour
defined in the cycle. If the starting point lies in the area to be machined
the TNC positions the tool beforehand in some cycles to set-up
clearance.
The turning direction with 81x cycles is longitudinal to the rotary axis
and lateral to the rotary axis with 82x cycles. The motions are contour-
parallel in cycle 815.
The cycles can be used for inside and outside machining. The TNC
takes the information for this from the position of the tool or the
definition in the cycle (see also "Working with turning cycles" on page
282).
In cycles with freely defined contours (Cycles 810, 820 and 815), the
programming direction of the contour determines the direction of
machining.
In cycles for turning you can specify the machining strategies of
roughing, finishing or complete machining.
Caution: Danger to the workpiece and tool!
The turning cycles position the tool automatically to the
starting point during finishing. The approach strategy is
influenced by the position of the tool when the cycle is
called. The decisive factor is whether the tool is located
inside or outside an envelope contour when the cycle is
called. The envelope contour is the programmed contour,
enlarged by the set-up clearance.
If the tool is within the envelope contour, the cycle
positions the tool at the defined feed rate directly to the
starting position. This can cause contour damage. Position
the tool at a sufficient distance from the starting point to
prevent the possibility of contour damage.
If the tool is outside the envelope contour, positioning to
the envelope contour is performed at rapid traverse, and at
the programmed feed rate within the envelope contour.