Programming Of Laser Scanning Path For Metal 3D Printing Based On Partitioning Strategy

As the key technology of increasing manufacturing,metal 3D printing is an important part of the high-end intelligent manufacturing field of "made in China 2025",which will have a profound impact and positive role in the development of industrial manufacturing in China.As the expression of energy loaded in metal 3D printing process,the laser scanning path has an important influence on the forming precision,warpage degree,mechanical properties,the service life of the laser and the processing efficiency,which is one of the key problems to be solved in the field of metal 3D printing.The core of this thesis is to study the laser scanning path planning of metal 3D printing.First,the square meshing method is studied.Through the simulation analysis,it is concluded that this method has an ideal application effect to the regular rectangular area.With closed filling method for support,the internal and external partition of convex polygon slices and the convex partition as well as the internal and external partition of concave polygon slices are given.The internal and external partition strategy and the convex partition strategy are proposed respectively.Compared with the square meshing method,under the premise of ensuring the warpage degree,mechanical properties and forming precision of the forming parts,they can increase the service life of the laser and improve the processing efficiency by reducing the number of scanning paths and free stroke.Aiming at the laser scanning path planning of convex polygon slices,the internal and external partition strategy is proposed.First of all,solve the largest inscribed rectangle of the convex polygon contour based on the geometric center as the border of the internal and external regions.Then the internal and external path connection is overall planned.The path of inner rectangle area is generated by the square meshing method.After the secondary partition of the external area,the closed filling method is used to generate the path of outer area.After the path is connected,the scanning path of the convex polygon slice is only one without free stroke.Simulation analysis verifies the feasibility and the great advantage in the number of paths and the free stroke of the internal and external partition strategy for convex polygon slices contour.Aiming at the laser scanning path planning of concave polygon slices,the convex partition strategy is proposed.First,convex partition method is used to concave polygon contour,generating several convex polygon subregion.Then according to the shape of each convex polygon subregion,select the internal and external partition strategy or adaptive scanning direction filling method for path generation.Each convex polygon subregion has one scanning path.Finally,the loading sequence of the subregion paths is optimized to obtain the optimal laser scanning path.Simulation analysis verifies the feasibility and the advantage in the number of paths and the free stroke of the convex partition strategy for concave polygon slices contour.