Research On Free Surface Flattening Algorithm And Numerical Control Machining

With the development of design technology, especially the emergence of computeaided design(CAD), beautiful and high quality surface can be designed easily withassistant of different tools. However it's difficult to calculate the flan area of surface. Inaddition, there are some kinds of free surface that can't be flatten with traditionaltechnology with the development of manufacturing technology. Therefore more and moreresearches on surface flatten have been made from 1990s because of the various fieldrequirements, but there isn't any accepted perfect method for free surface flatten. Howeveraccording to on the shape and size of flatten, shape and size of blank can be decidedaccurately and precision and quality of products can be improved profoundly.Based on researches made by predecessors, an algorithm for free surface flatteningbased on energy is put forward. In the procedure of surface flattening, surface ispartitioned at first with triangle, then triangles are mapped to plane. In importing energymethod for more accurate flatten, triangle edges are considered to be deformable bars inwhich energy will be accumulated when bars are deformed in flatten process. At lastflatten of free surface can be obtained and optimized with adjusting energy deposited inprocedure of mapping. Because the flatten algorithm is in respect of the form of theproblem, some kinds of free surface can be stretched with the algorithm presented in thispaper. Accordingly a software, SurfS, is developed to stretch free surfaces. The modulenumerical control can output program for machining surface based on information thatuser input, realize surface manufacture CAD/CAM integrative.Work of this paper is summarized as follows:(1). Deformation in flattening of free surface has been analyzed based on differentialgeometry. A surface flattening algorithm based on energy is put forward. This is auniversal algorithm to flatten surface with highly accuracy.(2). Transformed coordinates of points 3D grid of triangle got from the procedure ofsurface flattening to cutter location data(CLD), NC code is produced to machine the freesurface.(3). Software to stretch and machining free surface have be developed based onalgorithms put forward in this paper, so that the integration of CAD and CAM is realizedin some extent.(4). Practical example has been used to validate algorithm. The creative point: import the energy method and Delaunay triangle grid carvemethod which based on mapping to flatten free surface.