Research On Flank Milling Tool-path Planning Of Free-form Surface Based On Coupled Surface

At present,free-form surface has been widely used in industrial production.For the machining of free-form surface,the current production practice usually adopts the point milling method.Compared with the point milling method,the flank milling method has the advantages of high machining efficiency and good surface quality,which has attracted the attention of researchers.However,due to the diversity and complexity of free-form surface,the flank milling of free-form surface has not formed a mature theory and technology system.By using coupled surface method in differential geometry,this paper established a kind of flank milling envelope error model.Combined with design of experiment and the surrogate model calculation,the general theory and method for generating free-form surface flank milling tool positions are researched.Considering that the general free-form surface cannot be formed by one tool path,the processing band is divided by fitting a free-form surface using ruled surfaces.Then the initial tool position is generated.On the problem of obtaining the error between cutter envelope surface and the designed free-form surface on single tool position,feature target rods are used as the link between the tool surface and designed surface,and the envelope error model is established.The error objective function is proposed by using the equivalence of the minimum feature target pot condition and the envelope condition.The relationship between the tool position and the envelope error cannot be expressed by an explicit function,and can only be got by numerical simulation,which is time consuming.Therefore,the relationship between the tool position and the envelope error is presented by experiment design and surrogate model.To complete this task,the following three surrogate models are used:Face-centered cubic experiment design and a polynomial response surface model are used to plan the tool position.The results show that the algorithm can achieve high precision and stability.The error distribution is uniform.The orthogonal Latin square design of experiment and the radial basis function surrogate model are used to plan the tool position.The results show that the algorithm can obtain better error root mean square value.The algorithm is stable but error distribution is not as uniform as that of polynomial response surface method.The orthogonal Latin square design of experiment and Kriging tool planning agent model are used to plan the tool position.The results show that not only can the algorithm obtain better objective function value than that of radial basis function surrogate model,but also can obtain a uniform error distribution,while the algorithm is stable.In order to put the tool planning algorithm proposed in to use in the actual work more efficiently,the preliminary application was developed using MATLAB 2017a,with the functions of surface information importing and editing,processing band division,generation of initial tool position,single tool position test,tool position planning,showing tool position,outputting CLSF files,and so on.For this reason,on the basis of finishing tool position,the algorithm of non-cutting motion planning and semi-finishing tool position generation is added.In addition,in order to verify the effectiveness of the algorithm,CAM software NX 11.0 and Vericut 7.4 are used to simulate the machining process.Five axis NC machining center is used for processing experiments.The results show that the method proposed is reasonable and effective.