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Proceedings of CAD'14, 2014, 91-93
Machining Feature Recognition from In-Process Model of NC Simulation
Abstract. NC simulation is one type of virtual machining, which emulates the CNC machine and the cutter move, and depicts the material removal to better visualize the machining process. It can be done on the CNC controller of a shopfloor machine, or on an offline computer. Until now, its main goals are still confined to check an unproved NC program to avoid potential collisions with fixture elements, making undercuts, or leaving excess material. In our work, by making use of the simulated output—the In-Process Model (IPM), and re-establishing a model based on machining features, we extend the applications of NC simulation to build the feedback link from CAM/NC or shopfloor amendments back to CAD. This feedback link and the re-established feature model can serve for design improvements since we can compare this model with the original designed model, measure more reliable and accurate dimensions on this model, or use it for FEA and other applications. Actual research issues: The widely used NC simulation approach is the mesh-based virtual machining, whose output data of the IPM is a collection of triangles, without topological information. The IPM contains unwanted data—the offcut. Also the mesh data usually contains degenerated triangles (i.e. isolated vertices and edges) and incorrectly oriented triangles, or lacks of triangles data for building a solid. Therefore the first issue is to build a polyhedral B-rep model from the IPM.
Keywords. Machining feature recognition, NC simulation, In-process model, RE, STEP-NC