Siemens SINUMERIK 802D sl Programming Manual page 82

Movement Control Commands
3.5 Tool offset functions
Function
When CDON (Collision Detection ON) and tool radius compensation are active, the
control monitors the tool paths with Look Ahead contour calculation. This Look
Ahead function allows possible collisions to be detected in advance and permits
the control to actively avoid them.
When collision detection is off (CDOF), a search is made at inside corners in the
previous traversing block (and if necessary in blocks further back) for a common
intersection point for the current block. If no intersection is found with this method,
an error is generated.
Fig. 3-23
CDOF helps prevent the incorrect detection of bottlenecks, e.g. due to missing
information which is not available in the NC program.
The number of NC blocks monitored can be defined in the machine data (see
machine manufacturer).
Examples
The following are some examples of critical machining situations which can be
detected by the control and compensated for by modifying the tool paths.
In order to prevent program stops, you should always select the tool with the
widest radius from all of the tools used when testing the program.
In each of the following examples a tool with too wide a radius was selected for
machining the contour.
3-82
Collision Detection
SINUMERIK 802D sl/840D/840D sl/840Di/840Di sl/810D ISO Milling (PGM) - - 04.07 Edition
© Siemens AG 2007 All rights reserved
04.07