| 0. PrefaceAutomobile body is the key of the automotive industry development, and the body lies in the manufacture of stamping dies. The success of modern press technology is due to the successful development of the automotive industry, and body stamping accounts for about 30% proportion in stamping industry. Because of the continuous development of new automotive products, most new stamping technology is developed in the automotive stamping industry. Therefore, the automotive stamping industry is the driver of a new stamping industrial development and carrying out, especially for forming technology. Formability engineering analysis can solve all the stamping engineering and product problems. For example, how to determine the seriousness state of the press defect, what the pressing variables will impact pressing defects seriousness state, and so on. There are many available tools for the formability engineering analysis, and different tools have different functions and applications. Therefore, understanding engineering analysis enables stamping engineers to efficiently carry out stamping formability measurement and applications.With the maturity and application of CAE technology, the CAE software simulation analysis of existing body sheet metal forming can show a degree of plate defects, but there is no defect indication, causes, control methods and programs to eliminate defects, so stamping engineers can not further amend for the existing analysis results. Therefore, in order to improve the usefulness of CAE simulation results, according to sheet metal forming technology, it is important to apply the research results of stamping defect mechanism and solution to the development of post processing of CAE software.In this paper, we launched research on automotive panel stamping and forming theory and defects under the National Automotive Electronics major projects of high tech industry "CAD/CAE/CAM software platform for digital auto body parts fine design and manufacturing"(SDRC high tech 2042), the National Outstanding Youth Science Fund "The CAD expert system theory based KBE of stamping design and the research on the polymer forming theory and calculation method "(10125208) and the Ministry of Science and Innovation Fund "Stamping forming simulation technology applications". At the same time, carried out the "stamping defect system" development, and specifically analyzed typical examples.1. Sheet metal forming theory based on Universal Formability Technology and forming AnalysisFormability theory is the foundation of formability engineering experimental analysis. Different defect and quality concerns of sheet metal products need different formability analyses with different theoretical foundations. The development history of formability theories, in fact, parallels the improvement history of product quality, forming processes, and sheet metal properties. Today's stamping industry requires more nimble and robust procedures for stamping engineering and production stability control. Product quality specifications are tighter and tighter; forming processes are more and more complicated due to intricate product shapes. Advanced formability analyses, therefore, are needed to satisfy these stamping industry requirements. Base on Universual Formability Technology, this paper presents a new stamping approach, thus provide more accurate and reliable technology, it can focus on stamping performance, especially for surface quality and shape accuracy to conduct a comprehensive description.2. Fundamentals of strain measurements of sheet metal formingWhen a blank is stressed, the metal flows into the die cavity, resulting in a blank shape change. The blank shape change continues until a desired part is obtained during the loading process. When the metal flows, deformation, which is measured with strain, occurs. No deformation means no stamping. One of the major formability engineering analyses is to measure strains and strain distributions regarding different stamping quality concerns. Mastering basic deformation concepts, therefore, is the foundation for conducting strain measurements and analyses. The measured strain information, which includes strains and their orientations in grids, are raw data. Generally, the raw data cannot be applied directly for formability engineering analyses; they have to be transferred into formability indexes. The formability indexes have engineering meanings and are directly used for evaluating the ease or difficulty of making qualified stampings. In order to obtain formability indexes, the obtained raw data (strain information) needs to be transferred into extreme strains and strain gradients, while the displacements are measured directly.3. Development for sheet forming defects systemTraditional finite element method can only made basic indicates function for forming defects, and can't further proposed improvement program. Take stamping defect diagnosis, resolution, prevention of the implementation methods, processes, feasibility, reliability analysis for conceptual analysis, mold design, mold manufacturing at different stages to meet the needs of practical engineering. The software does not rely on other CAE software, directly analysis and calculate post processing results.4. Fine analysis of split, wrinkle, shape change defects for auto panel stamping.The internal surface rupture is a defect which is difficult to resolve. This defect often takes place after putting mold into production, make production stability lower, scrap rate increased and resulting in greater economic losses. Sheet metal forming industry, particularly in the automotive stamping field that need to develop a forming technology, to processing a large number mechanical information obtained from the finite element analysis, physical testing, circle grid analysis and so on, and determine the degree of difficulty of manufacturer qualified stamping parts. Analysis on sheet metal forming theory and forming properties can use to analysis mechanical information and establish forming index to rigorously measure various types of stamping defects. In this fifth part we indicate rapture defect through KMAS/UFT system,and give the amount of metal flow conditioning advice and programs by simulation.Wrinkle in stamping process may not only result in a large number of waste, and easily to scratch mold. Even if the wrinkle has been flattened in the stamping later, there will leave traces in the product surface and affect the appearance. In this sixth part we indicate winkle defect through KMAS/UFT system,and give the amount of metal flow conditioning advice and programs by simulation.Elastic recovery will occur after stamping parts unloading. The relative design of stamping parts after unloading part size deviation is called springback. On the other hand, due to Non uniform stress distribution in stamping or Part of local geometric features constraint making of non uniform stress distribution, causing the overall shape of stamping parts "distortions" or "warp" after unloading, caused stamping parts shape change. Usually, springback and warping collectively referred to as shape change. In this seventh part we indicate shape change defect through KMAS/UFT system,and give the amount of metal flow conditioning advice and programs by simulation.
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