Siemens SINUMERIK 840D sl Operating Manual page 448

Programming technological functions (cycles)
8.5 Contour turning- only for G code programs
Contour transition elements
As transition element between two contour elements, you can select a radius or a chamfer
or, in the case of linear contour elements, an undercut. The transition element is always
attached at the end of a contour element. The contour transition element is selected in the
parameter screen of the respective contour element.
You can use a contour transition element whenever there is an intersection between two
successive elements which can be calculated from the input values. Otherwise you must use
the straight/circle contour elements.
Additional commands
You can enter additional commands in the form of G code for each contour element. You
can enter the additional commands (max. 40 characters) in the extended parameter screens
("All parameters" softkey).
You can program feedrates and M commands, for example, using additional G code
commands. However, make sure that the additional commands do not collide with the
generated G code of the contour. Therefore, do not use any G code commands of group 1
(G0, G1, G2, G3), no coordinates in the plane and no G code commands that have to be
programmed in a separate block.
Additional functions
The following additional functions are available for programming a contour:
● Tangent to preceding element
● Selecting a dialog box
● Close contour
From the actual position, you can close the contour with a straight line to the starting point.
Producing exact contour transitions
The axis moves in the continuous path mode (G64). As a result, contour transitions such as
corners, chamfers or radii may not be machined precisely.
If you wish to avoid this, there are two different options when programming. Use the
additional programs or program the special feedrate for the transition element.
● Additional command
For a contour, first program the vertical straight line and then enter "G9" (non-modal exact
stop) for the additional command parameter. Then program the horizontal straight line. The
corner will be machined exactly, since the feedrate at the end of the vertical straight line is
briefly zero.
● Feedrate, transition element
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You can program the transition to the preceding element as tangent.
If two different possible contours result from the parameters entered thus far, one of the
options must be selected.
Operating Manual, 03/2013, 6FC5398-7CP40-3BA1
Milling