Siemens SINUMERIK 840D sl Programming Manual page 314

Tool radius compensation
10.5 Collision monitoring (CDON, CDOF, CDOF2)
Note
The number of NC blocks that are included in the collision detection, can be set via machine
data.
Example
Milling on the center point path with standard tool
The NC program describes the center point path of a standard tool. The contour for a tool that
is actually used results in undersize, which is shown unrealistically large to demonstrate the
geometric relationships in the following figure. The control also only has an overview of three
blocks in the example.
Figure 10-5
Since an intersection exists only between the offset curves of the two blocks N10 and N40,
the two blocks N20 and N30 would have to be omitted. In the example, the control does not
know in block N40 if N10 has to be completely processed. Only a single block can therefore
be omitted.
With active CDOF2, the compensation motion shown in the figure is executed and not
stopped. In this situation, an active CDOF or CDON would result in an alarm.
Further information
Program test
To avoid program stops, the tool with the largest radius from the range of used tools should
always be used during the program test.
Examples of compensation motions for critical machining situations
The following examples show critical machining situations that are detected by the control
and compensated through modified tool paths. In all examples, a tool with too large a radius
has been used for the machining of the contour.
314
Compensation motion for missing intersection
Programming Manual, 09/2011, 6FC5398-1BP40-2BA0
Fundamentals