Siemens SINUMERIK 840D sl Operating Manual page 214

Programming a cycle
4.6 Contour turning
Feed interruption
To prevent the occurrence of excessively long chips during machining, you can program a
feed interruption. Parameter DI specifies the distance after which the feed interruption should
occur.
Machining type
You can select the machining mode (roughing or finishing). During contour roughing, parallel
cuts of maximum programmed infeed depth are created. Roughing is performed to the
programmed allowance.
Approach/retraction during roughing
1. The cycle starting point is calculated internally and approached with G0 in both axes at
2. Roughing without relief cut elements:
● The paraxial infeed to the current depth is calculated internally and approached with G0.
● Approach of paraxial roughing intersection point with G1 and at feedrate F.
● Round parallel to the contour at contour + final machining allowance to the last roughing
● Lift-off by the amount programmed under VRT in each axis and retraction with G0.
● This sequence is repeated until the total depth of the machining step is reached.
● When roughing without relief cut elements, retraction to the cycle starting point is carried
1. Roughing the relief cut elements:
● Approach of the starting point for the next relief cut axis by axis with G0 When doing so,
● Infeed along the contour + finishing allowance with G1/G2/G3 and FY.
● Approach of paraxial roughing intersection point with G1 and at feedrate F.
● Round to the last roughing intersection. Lift off and retract as in the first machining
● If there are further relief cut elements, this sequence is repeated for each relief cut.
Approach/retraction during finishing
● The calculated cycle starting point is approached in both axes simultaneously with G0
● Motion continues with both axes simultaneously and with G0 minus an amount equivalent
● Finish cutting along the contour with G1/G2/G3 and FS.
● Retraction to starting point with both axes and G0.
214
the same time.
intersection point with G1/G2/G3 and F.
out axis by axis.
an additional cycle-internal safety clearance is observed.
section.
and tool nose radius compensation is selected.
to the final machining allowance + tool nose radius + 1 mm safety clearance ahead of the
contour starting point, and from there with G1 to the contour starting point.
Operating Manual, 01/2008, 6FC5398-7AP10-0BA0
HMI sl Turning