Protection against collisions in the machining process
May 11, 2009
Systems only PC-based off-line can provide simulations for the prevention of collisions, not amounting to a definitive solution, that the virtual world does not always correspond to reality. For example, what happens if a tool breaks down and is replaced? To adapt simulation to reality, new tool data must be loaded on the PC, integrated into the CAM system and calculate again the simulation. The same applies to modifications made without much anticipation in the mooring device or machine.
On the other hand, online systems integrated in the CNC - as the checking of Fanuc 3D interference - can monitor the actual movements of the machine tool in real time and avoid collisions with virtually 100 per cent of security - even during the operations of preparation. The check of interference in 3D, which is available for controls of CNC Series 30i/31i model to Fanuc, is integrated into the core of the NCC and makes use of enveloping geometric elements (flat, rectangular parallelepiped and cylinder) that are defined in all areas where there is a risk of collision. CNC control takes into account this spatial information, along with current data from the tool, in the calculation of the movements of the axes. Simultaneously to the interpolation of the axes, the main CPU calculates all the objects within the model of interference in 4ms cycles. When there is the possibility of a collision, the machine is for, as the last step of the interpolation before entering a given geometric figure does not take place. Given that the interference check only has to examine small volumes of data, it does not affect machining.
The check for interference in 3D is easy to use. The necessary geometrical data can be entered in the CNC, and tool data are automatically transferred. In complex cases, however, it is more comfortable and up to 40% faster, calculate and view the settings on a PC by means of auxiliary software developed by Fanuc. This software also allows the exchange of data with 3D CAD systems.
The check for interference in 3D enjoys great success - many manufacturers of machine tools, as Stama, PCI, Cincinnati LAMB, Chiron, Hamuel, Wilhemin, Maier, Recomatic, Waterjet, Heckert, Heller and Biglia are installing this software anticolisiones. These manufacturers confirm that more are increasingly end-users specifically requesting the check for interference in 3D to protect their machining.
