Siemens SINUMERIK 840D sl Operating Manual page 526

Programming technological functions (cycles)
10.5 Contour turning - Milling/turning machine
Producing exact contour transitions
The continuous path mode (G64) is used. This means, that 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
If you have chosen a chamfer or a radius as the transition element, enter a reduced feedrate
in the "FRC" parameter. The slower machining rate means that the transition element is
machined more accurately.
Procedure for entering contour elements
526
1. The part program is opened. Position the cursor at the required input
position, this is generally at the physical end of the program after M02 or
M30.
2. Contour input using contour support:
2.1 Press the "Contour turning", "Contour" and "New contour" softkeys.
2.2 In the opened input window, enter a name for the contour, e.g. contour_1.
Press the "Accept" softkey.
2.3 The input screen to enter the contour opens, in which you initially enter
a starting point for the contour. This is marked in the lefthand navigation
bar using the "+" symbol.
Press the "Accept" softkey.
3. Enter the individual contour elements of the machining direction.
Select a contour element via softkey.
Operating Manual, 05/2017, A5E40868956
Milling