Numerical Simulation On The Process Combined Splitting Spinning Preforming And Multi-Pass Spinning Forming Of Al-alloy Rim

With the development of human society, environment and energy issues becomeincreasingly prominent and automobile light weight has been paid more and more attention.In the process of automobile lightweight, aluminum and aluminum alloy are widely used inthe manufacture of automobile parts due to their unique characteristics. Because of thebeautiful appearance, high strength, good heat dissipation and so on, the aluminum alloy rimreplaces the steel rim and becomes the symbol of high-grade car.Currently, three production processes for aluminum rim are used, that is, casting, forgingand spinning. Compared with the other two methods, spinning has the advantages of highforming precision, high material utilization and low cost, and becomes the developmentdirection of the rim manufacturing. This paper put forward the forming process for aluminumalloy rim, the process combines splitting spinning and multi-pass spinning, and it is a verycomplicated plastic forming process. To study the forming regularity of the rim spinningforming, the reasonable FEM model of the spinning has been established based on theanalysis of the forming process. The spinning forming process was simulated by usingsoftware ABAQUS/Explicit, and the distributions of stress and strain for splitting spinningand multi-pass spinning processes have been obtained. The influences of the parameters onthe spinning forming process also have been obtained. The results provide the basis todevelop the spinning process.The splitting spinning forming process was numerical simulated, and the distribution ofstress-strain and the influence of the process parameters on the forming results were obtained.In the numerical simulation of the splitting spinning process, the calculation was failed due tomesh distortion. In order to solve this problem, with the application of ALE method in thesimulation process, the grid quality was improved, and the mesh distortion was eliminated.The satisfactory results were obtained. The results show that the distribution of equivalent stress is inhomogeneous in the splitting spinning process, and the maximum of equivalentstress concentrates in the contact area between the roller and the blank. The maximum ofequivalent plastic strain concentrates in the splitting area of the blank. With the increase ofsplitting angle and feed ratio, the uneven degree of forming flange is reduced and the formingprecision gets bad.The multi-pass spinning processes were simulated, and the variation of the maximum ofequivalent stress and equivalent plastic strain for each pass were obtained. The results showthat the maximum of equivalent stress concentrates in the contact area between the roller andthe blank in the multi-pass spinning processes. But the maximum of equivalent stress alsoexists in the root zone of the blank in the first and second pass forming process. Themaximum of equivalent plastic strain appears in the contact area between the roller and theblank, and the region form a strain ring which gradually moves outside along with carryingout of the forming process. But the strain ring also appears in the root zone of the blank in thefirst and second pass forming process.The influences of feed ratio, spindle speed and radius of roller’s round corner on theequivalent stress/strain and the spinning force were obtained by changing the levels of theparameters. The results show that with the increase of feed ratio, the maximum of equivalentstress and equivalent plastic strain increase firstly and then decrease in the first and secondpass. With the increase of spindle speed and radius of roller’s round corner, the maximum ofequivalent stress and equivalent plastic strain increase in three passes. With the increase offeed ratio, spindle speed and radius of roller’s round corner, the spinning force of each passincreases.On the basis of the numerical simulation, the process parameters and the level of eachparameter were selected reasonably, and then the orthogonal optimization experiment wasdesigned by using the orthogonal table. The influences of feed ratio, spindle speed, radius ofroller’s round corner and friction coefficient on the offset and the minimum thicknessdeviation have been studied with the orthogonal experiment data processed by SNR, based onrange-mean analysis and variance analysis methods. The influences of feed ratio and frictioncoefficient on the offset are significant, and those of the spindle speed and radius of roller’s round corner are not obvious. The radius of roller’s round corner has the greatest influence onthe minimum thickness deviation, followed by spindle speed, and then followed by the feedratio. The optimal combination of the parameters has been achieved in the scope of theoptional parameters, and the best appropriate matching process parameters are feed ratio of1.2mm/r, spindle speed of2.5r/s, radius of roller’s round corner of14mm and frictioncoefficient of0.05. The optimizing process parameters values of rim multi-pass spinning areobtained by numerical simulation and used to experimental analysis. Measured results for theprecision of formed parts verifies the credibility and correctness of the simulation results.