Sheet Metal Forming Mould Correction For Springback Based On Nurbs

Springback in sheet drawing process seriously reduces the accuracy of automobile panels mould, so in-depth study of springback compensation,including a good solution to the springback problem and the research system of mold deviation elimination, is extremely necessary.Displacement adjustment method (DAM) is one shape global deformation (SGD) method which compensate mould geometry deviation by modifing the mould surface in the opposite direction to springback. However, many research problems are encounterd in the DAM study, such as compensation direction, mould mesh smoothing, and deviation convergence, which are the key factors that determine the accuracy of compensation, and more importantly, the application of DAM. This research conducts a study on sheet springback controlling method in automobile panel drawing die manufacturing. This thesis mainly deals with:1.Key issues of DAM are Systematically expounded, such as theory foundation of DAM, compensation direction, mould mesh smoothing."NURBS-based surface generation algorithm and point cloud cauculation method are introduced in detail.These laid the foundation for the programming of springback compensation.2.With suitable data structure for pringback compensation program designed, corresponding relationship between the parts mesh and mould mesh built, C language source code for mould surface correction written, springback compensation function is at last achieved through a compensation program.3. The program in this thesis is used first in the deviation compensation of V-shaped parts and car roof, then in the springback compensation of car B-pillar drawing mould based on FEM.Point cloud of actural part is obtained by3DSS three-dimensional scanner scanning. Manufacturing deviation is measured in reverse software, and the compensation result is verified.