Siemens SINUMERIK 840D sl Operating Manual page 203

For each contour element, you must parameterize a separate parameter screen.
The coordinates for a horizontal or vertical line are entered in Cartesian format; however, for
the contour elements Diagonal line and Circle/arc you can choose between Cartesian and
Polar coordinates. If you wish to enter Polar coordinates you must first define a pole. If you
have already defined a pole for the starting point, you can also refer the Polar coordinates to
this pole. Therefore, in this case, you do not have to define an additional pole.
Parameter entry
Parameter entry is supported by various help screens that explain the parameters.
If you leave certain fields blank, the geometry processor assumes that the values are unknown
and attempts to calculate them from other parameters.
Conflicts may result if you enter more parameters than are absolutely necessary for a contour.
In such a case, try to enter fewer parameters and allow the geometry processor to calculate
as many parameters as possible.
Contour transition elements
As a transition between two contour elements, you can choose a radius or a chamfer. 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.
The contour end is an exception. Although there is no intersection to another element, you can
still define a radius or a chamfer as a transition element for the blank.
If the value of the transition element is "NULL", no transition element will be parameterized.
Additional functions
The following additional functions are available for programming a contour:
● Tangent to preceding element
You can program the transition to the preceding element as tangent.
● Dialog box selection
If two different possible contours result from the parameters entered previously, select the
desired contour.
Confirm the selection.
● Close contour
From the current position, you can close the contour with a straight line to the starting point.
Grinding
Operating Manual, 05/2017, A5E40869190
Programming technology functions
9.1 Programming contours
203