Research On High Speed Milling Of Nodular Cast Iron In Different Cutter Path Strategies

Nodular cast iron, a kind of material that has excellent mechanical properties, is being increasingly used for the area of automobile, agricultural machinery and so on industries. Greater demands are placed on the surface accuracy and economics of the processed nodular cast iron with the progress of modern industry. Better machining efficiency and surface roughness can be obtained, owning to the appearance of high-speed cutting technology. The material removal rate and cutting efficiency can be affected differently by different tool paths in the process of high speed machining. And yet, nodular cast iron itself belongs to heterogeneous material and it is the internal spherical graphite that make the processing unstable.the cutting tool wear serious and the processing efficiency low. Hence the research on high-speed cutting nodular cast iron has significant practical meaning to improving the economics and surface accuracy of the processing of nodular cast iron.In this paper, we choose nodular cast iron as the processing material. Through experiment and theoretical analysis, the nodular cast iron was high-speed milled with three different tool paths of single direction cutting, bidirectional line cutting and ring-cutting. Besides, the variation of cutting tool wear, milling forces and surface 3-D roughness in high-speed milling nodular cast iron was analyzed.Firstly, the influence of spindle speed on the tool wear was analyzed by selecting two kinds of spindle speed of 13270r/mm and 15723r/mm in the tool path of bidirectional line cutting. Furthermore,the trend of the milling force based on the tool wear were studied by high-speed milling nodular cast iron with three different tool paths of single direction raster cutting, bidirectional line cutting and ring-cutting. Where, the experiment was performed with three different axial depths of cut of 1.5mm、2mm and 2.5mm in each tool path. Besides, we analyzed the effects of axial depth of cut on the processing time, material removal amount and material remove rate by variance analysis and contributive rate analysis to the experimental result with the two-factor repeated experiment method.Then, for the three-dimensional surface roughness of the nodular cast iron processed with different tool paths, we used the method of orthogonal experiment, the characterization function of three-dimensional surface roughness was finished by the detail illustration for the surface morphology characteristics of the three-dimensional roughness and adjusting cutoff wavelength, ratio of the objective,measurement field and filter parameters etc. Thus the foundation of detection to the subsequent three-dimensional surface quality was laid.Finally, for the three-dimensional surface roughness and milling forces in the processing of nodular cast iron with different tool paths, we proposed the effect regularity of the four cutting parameters which are depth of cut,spindle speed feed speed and radial depth of cut to the surface roughness and milling forces with the three different milling ways of single direction raster cutting, bidirectional line cutting and ring-cutting by the methods of orthogonal experiment and range analysis and variance analysis. The method of partial least-squares regression (PLS) was used for the modeling of milling forces based on the cutting parameters and three-dimensional surface roughness. Furthermore, the accuracy of the model was verified available with and F test and t test.