A CAD/CAM System Research For The Gap Sheet Metal CNC Incremental Forming

The demand for sheet metal forming parts is increasing with the rapid industrialdevelopment; in particular, sheet metal forming occupies a pivotal position in the aerospace,shipbuilding and automobile industries. In the paper, five-axis CNC incremental formingtechnology for the gap sheet was researched. A CAD/CAM systems of the gap sheet metalCNC incremental forming based on parasolid modeling kernel was developed, which had theimportant practical significance for the promotion of the technology. The main functions ofthe CAD/CAM were as follows：First, The identification and extraction functions of sheet model feature points, edges,surfaces was proposed using Parasolid modeling kernel functions through researching systemsCAD module.Interactive identification extraction method for interactive systems wasproposed, and a method to automatically identify and extract the model of the gap sheet metalis proposed. At the same time, filling and repairing the gap features to achieve surfacereconstruction, in this section the contents of the system CAD was completed, as the basis ofthe CAM module.Then, the CAM module content of the systems was researched, including trajectorygeneration, interference checking, simulation and automatic generation of NC code. Thetrajectory generation included constant tool-path generation for5-axis sheet metal CNCincremental forming and3-dimensional laser of5-axis cutting path generation. The problemsof the radius compensation and identification for pressing angle of tools were considered inthe generation of constant tool-path. Considering the laser beam radius compensation whencutting path was generated, the cutting face offset method was proposed to implement cuttingpath generation. The5-axis CNC incremental forming and3-dimensional laser of5-axiscutting are both5-axis machining, and the increasing of spindle freedom is bound to considerthe interference checking issue of the extrusion tool or laser gun, Parasolid interferencechecking functions were used to solve the problem of interference checking. Finally, simulation and the method of automatic generation of NC code were researched. They areboth CAD/CAM systems essential functions.The proposed algorithms of the above CAD/CAM functions was realized the in theWindows XP operating system environment using Visual C++and OpenGL, and the fileformat for the Parasolid model inputted. Application cases showed, the developed CAD/CAMsystem of gap sheet incremental forming can achieve the above functions stably and reliably.