Research On Moulding Surface Designing Method Compensating Springback In Automobile Body Covering Parts

There is springback phenomenon when the covering parts of automobile body are instamping process, because of this, the springback of forming part can not meet theaccuracy requirements. Every year, it will make a lot of loss just because of springbackproblem, so springback problem is the core negative restriction part for stampingforming.Process control can make some sense for springback control, however, which cannot eliminate springback fundamentally. So to study whether can eliminate thespringback by the way of mould surface through the source of stamping forming will bemeaningful.In order to realize the compensation of the parts springback, designing the moldprofile by considering springback. For the design of two-dimensional curved surface andsimple three-dimensional curved surface, such as U, V mould surface and sphericalsurface, the inverse solution of springback can be used to get the radius of curvaturebefore springback, which is the relationship before and after springback, and mold profiledesign can be got directly; For mold profile of general three-dimensional curved surfacedesign, it’s hard to work out irregular surface inverse solution directly, mould designcompensation method is more and more widely used with the method of finite elementsimulation, which can be used to solve model springback. However, finite elementsimulation is still not a convenient way, since the mold profile only can be got bysimulating and repairing model again and again.For the parts of general simple three-dimensional curved surface, according to partssurface, a method for solving mold profile is provided. The main process is to usediscrete ideas to discrete the three-dimensional curved surfaces, after this, the discretemicro element can be approximately trade as three-dimensional spherical surface. If theinverse solution theory of three-dimensional spherical surface is used, the curvature radius before springback can be got. Then three-dimensional curved surface can be got bydealing with the surface micro element before its springback.In order to verify if the theoretical result is feasibility and correct, the specialsoftware Dynaform, is used for Stamping forming simulation, according to the simulation,not only the size of stamping parts before and after springback can be observed, but alsothe difference between stamping parts with compensation method and ideal parts can begot.According to the simulation, On one hand, because of the large and thin automotivecovering parts, the springback phenomenon is obviously existed in punch formingprocess, if not be eliminated, which can highly affect the size and accuracy of stampingparts. On the other hand, the application that discrete theory and inverse solution theoryof three-dimensional spherical are both used on generally simple irregularthree-dimensional curved surface design can largely reduce the error between ideal partsand stamping parts with compensation method.