The Modeling And Simulation For Surface Topography In High-Speed NC Milling

In the modern mold production, the proportion of free-form surfaces continuously increased,the design of internal structure and outer shape of plastic parts becoming more and more complicated, simultaneously, higher precision and surface quality are demanded, all these bring forward higher requirements to the mould manufacturing. Therefore, the investigation on surface topography simulation for free-form surface machining has great significance theoretical and practical application to mould manufacturing.In this paper, based on the modeling for prediction of milling force about ball milling and the predigested course of milling, and the expression of the cut sword line, establish the model of the surface topography innovation, the main content and achievements can be summed up as follows:(1) Ball milling cutters milling force prediction model is established. The tool is simplified as a cantilever beam structure, according to the empirical formula between the load and the cutting tool's milling force, considering the tool eccentricity, the deformation and thermal deformation, derived the instantaneous chip thickness expression under three-dimensional feed, Established and analyzed the modeling for ball milling Force.(2) The established for surface topography prediction model. Using graphic matrix transformation principle to find any point on the cutting edge of the trajectory equation, To get the tool movement envelope body. Consider the effected of eccentricity of the tool installation, tool heat stress and deformation to the path of tool, Given the changes in tool path, Expand the Z-map method to free surface machining, Through Boolean operations, have a created model of surface topography.(3) By MATLAB simulation software the prediction model is simulated. First, simulation for the milling force model, obtain the curve versus time that the ball mill of three mutually perpendicular directions of the cutting force Fx,Fy,Fz; Then, Simulation for the model of surface topography, the compressor blades as the research object,by Ansys software analyses the parameters of cutting speed v_c , processing angleξand axial depth of cut a_p effect on surface topography, Compared and analyzed the curve of testing and simulating.