Study On Tool Path Planning For Five-axis Machining Based On The NX Development

With rapid development of the aviation industry,national defense industry,the means of delivery,the power and mold industry,the demand for the high-end equipments with excellent performance is increasingly urgent.As a result,a large number of key parts of the complex surface shapes with high performance requirements is in emergence.Five-axis numerical control technology based on CAD/CAM is the main instrument of free-form surface machining.Due to more complexity of the technology of five-axis machining compared to that of the three-axis machining,the tool path planning in NC machining programming is still a key issue.Generating an excellent tool path has a significant impact on the feasibility of machining,the processing efficiency and the surface quality.In general,there are different tool path planning algorithms for different problems.the main difference among these is the differences of the tool step and scollop height calculation method.From the angle of the processing precision,calculation reliability and actual application,the paper gives a detailed description of the differences in tool path planning algorithms.Then the paper explains methods of calculation of the tool step and scollop height.Based on the local interference,we can calculate the tool axis vector at each contact point,that makes tool path,tool axis vector and the surface differential geometry structure link with each other.Based on the iso-scallop method process,select a border as an initial path,then calculate cutter contacts based on discrete tool step,calculate the corresponding cutter contact due to line spacing formula,finally,use the cubic spline curve fitting the adjacent cutter contacts until coverring the entire surface.Based on the development environment of Visual Studio and NX,paper uses NX Open API and NX Menuscript language to make secondary development.By reading the machined surface and initially selected path information,the surface concave curvature returns to the dialog box,and then by selecting the cutter radius,step discrete accuracy,and scollop height,NX generates the tool paths,implementing the tool-path planning algorithm based on the paper.From the total length of the tool path,theoretically machining time and simulation quality of the processed surface,the paper compares the proposed algorithm of tool path with the traditional iso-scallop method and the parallel sections method,the proposed cutter planning algorithm is verified to be correct and efficient.In addition,the discussion has been made to explain why the processing efficiency is not significantly improved and to give the factors that surface scollop height is not the values in theory.