Prediction And Experimental Analysis Study On Surface Topography Of Milling Machining Of Splicing Mold

There are grooves,corners,bulges,depressions and other characteristics on the mold surface of the automobile cover parts.These features are mostly made of whole and insert hardened steel milling.Because the automobile cover mold are made up of these materials,and splicing materials in the milling process milling characteristics have undergone tremendous changes,which has a serious impact on the surface quality.In this paper,the surface quality of Cr12 Mo V hardened steel splicing experimental workpiece is taken as the research object,the following research is carried out on the surface topography of the spliced mold processed by milling method.Firstly,the formation mechanism of surface topography is analyzed,the geometric model of the ball-end milling is described,and the edge line of the ball-end milling is discrete.Considering the geometric factors and processing parameters for the convex curved workpiece and the rotation and feed movement of the ball-end milling is transformed from the tool coordinate system to the workpiece coordinate system according to the principle of matrix transformation,the moving trajectory equation of any discrete point on the tool edge is obtained.Then,the condition of the cutting edge discrete points is judged,and the control point theory of NURBS surface is introduced,the discrete points to be preserved involved in cutting are extracted and the surface topography is reconstructed based on the control points of NURBS surface,this method can be used in a small number of simulation points to reconstruct the need to simulate the topography.Secondly,the trajectory of any discrete point on the tool edge line is expressed by the equation,and then the trajectory of the discrete point of the tool edge line with the impact vibration factor is represented by the mathematical equation,the effects of impact vibration on the topography under different milling parameters are simulated and analyzed.Finally,the machining experiment of Cr12 Mo V hardened steel spliced workpiece under different milling parameters is carried out,and the comparison between the simulation diagram and the experimental diagram is used to analyze and verify the reliability of the simulation model.Then based on the fractal dimension theory,the surface topography under the influence of impact vibration is indirectly analyzed and the two-dimensional surface roughness under different parameters is calculated.According to the fractal dimension theory and the twodimensional surface roughness,the surface topography under impact vibration is analyzed synthetically,and the most ideal milling parameters are found out,which has important reference significance for the actual milling.