Research On Automatic Programming Technology Of Five-Axis Cutting Machining Of Space Curve

The development of automatic programming technology plays an important role in the development of numerical control technology.At present,there are not many researches on automatic programming algorithms for five-axis cutting of space curves at home and abroad.Although the mainstream CAD/CAM software has corresponding solutions,the operation is relatively complicated,the algorithm is commercial closed,and most of the core technologies are in foreign countries,which is not conducive to the development of automatic programming technology in the field of five-axis cutting in China.Firstly,the four-layer architecture and basic data structures of the program are designed,and the DXF,STL and OBJ file parsing and two-dimensional primitive discrete algorithm are studied.Then the trajectory generation algorithm of 2D curve mapping to regular surface is studied.Through the one-to-one mapping relationship between the surface and the unfolding plane,the trajectory mapping method of the expandable regular surface such as the cylindrical surface and the conical surface is derived.For the non-expandable surface of the spherical surface,a reference point based fixed-length mapping algorithm is proposed for trajectory mapping,and the distortion of the mapping trajectory can be reduced with respect to the vertical projection.Then,the trajectory generation algorithm of two-dimensional curve mapping to triangular mesh free-form surface is studied.The reference point based fixed-length mapping algorithm is used to derive the calculation method of the tool position information by establishing adjacency triangle topology,projecting reference point and intersecting the triangular mesh with vertical plane of forward direction.The topology generation time complexity is optimized to O(N)by proposing a grid search based adjacency triangle topology generation algorithm and a CAD-integrated adjacency triangle topology generation method.Then,the trajectory generation algorithm of two-dimensional curve mapping to single-section surface is studied.The calculation method of tool location information is derived by the equal relationship between the distance of the two-dimensional curve and the arc length of the section and the classification calculation of the section.The section search time complexity is increased to O(logN)by a improved binary search algorithm.The single-section surface trajectory mapping algorithm is extended to the two-section trajectory calculation method in three steps.Then the intersection trajectory generation algorithm of cylindrical surface and arbitrary section cylinder surface is studied.The intersection calculation method of trajectory point information is derived by cross section discrete,region point identification,intersection surface segment extraction,surface segment classification and intersection of the busbar with the cylindrical surface.Finally,the process craft of tool axis inclination in cutting process is analyzed.The tool axis inclination compensation algorithm is designed,and the AB and AC five-axis post processing methods are studied.Based on the research and design of the above algorithm,the automatic programming software for five-axis cutting of space curve is implemented by MFC and OpenGL.The trajectory generation algorithm,the tool axis inclination compensation algorithm and the five-axis post processing algorithm on the surface are implemented.Through the function of five-axis path tool motion simulation and the output of the NC code,the correctness of the generated tool path is verified.