| In our country, the transportation by railway is a very important mode for persons andmaterials transfer and greatly improves our country economy developing. With the rapiddevelopment of economy, the requirement of the railway vehicles increases remarkably andits quality is demanded better and better. The railway vehicle made in carbon steels is a veryimportant kind of train and the requirement of the trains is very large. However, for the lag inthe vehicle manufacturing technology, especially the parts’ manufacturing technology, thequality of car body parts is not good commonly. The quality and competition of the vehicleis therefore degraded badly. Now the vehicle manufacturing factories are very urgent tograsp the advanced parts manufacturing technology to improve the quality of the car bodyparts.The side column is very important structural part in carbon steel car body. Its produceprocess is that the blank is made firstly by punching process and then is stamped forming toget a finished part. However, for the lagging in manufacturing technology, the blank hasmany defects, such as the low quality punching cross section, great burrs, the bad precisionof the moon gap contour etc., which makes the finished parts bring the defects of the overlarge error of the part edge. In addition, the defects cannot be solved for a long time and thefactories are therefore affected seriously. So the punching process of the side column blank isdeeply researched in the thesis by the method of simulation and experiment. The mainresearch work and conclusions are as follows:The punch process of the side column blank’ moon gap is simulated by DEFORM-3Dsoftware. The problem of the punch–die clearance affecting the blank punch cross sectionand burr size is analyzed. The proper punch-die clearance that very small burr emerges isthought to be5%-8%blank thickness by the optimizing method and an experiment is carriedout to prove the conclusion. The moon gap contour defect of the side column blank is studied by simulating andoptimizing. Firstly a characteristic part of the side column with a pair of sunken areas istaken as an example; its blank’s geometrical model is established. Then the stamp formingprocess of the blank is simulated by Pam-stamp software. The formed part edge line degreeis tested and the error data is acquired. Based on these error data the blank’s moon gapcontour is compensated and modified. Then the stamp forming process of the modified blankis simulated to get the edge line degree error data of the formed part to modify the blank’smoon gap contour again. By the iterative calculation method the optimized moon gapcontour data is obtained. The simulated edge error of the formed part by the blank with thecontour of the obtained data is only0.22mm, which is qualified completely compared withthe designed precision. The obtained contour data can also be used to design the surfacecurve of the die and punch of the tools stamping the moon gap.Based on the punch-die clearance data and the blank’s moon gap contour data acquiredin the former study, a test blanking die is designed and an experiment for the blank moon gappunching is carried out. The results show that the blank’ punching cross section is very goodand no evident burrs emerge. With the trial blank a stamp forming experiment is performedand the edge line degree error of the formed part is only0.31mm. It is identical with theformer simulation result. It also proves that the blank’s moon gap contour data determinedby simulation is precise and the relative research work is correct also. |
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