Papers by Keyword: Stamping

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Authors: Chang Yong Chu
Abstract: Two graphs are introduced to describe the precedence and cluster constraints among stamping operations, i.e., operation precedence graph and operation adjacency graph. A graph colouring algorithm clusters the operations based on both the precedence and adjacency graphs to form joint operations. A joint operation matrix is then generated. A matrix based algorithm is presented to iteratively order the joint operations to generate the final sequence according to the index of priority for each operation. The algorithm is implemented in C++ and is fully integrated with SolidWorks CAD system. A case study is presented to illustrate the algorithm.
Authors: Dong Won Jung, Bong Chun Kim, Dong Hong Kim, Duc Toan Nguyen
Abstract: The purpose of this study is to evaluate the influence of the scatter in mechanical properties and stamping process parameters on an industrial sheet metal forming process. Based on a previously optimized forming process, a robustness analysis has been performed. The robustness analysis clearly showed production problems for the part not initially revealed by the analysis of the process that was trimmed for “optimality”. The sensitivity of the results on the variation of the parameters was evaluated. It was shown that all parts of the sheet do not react equally sensitively to the variation of the input. Zones of critical response could be identified in accordance with the zones on the actual part that showed failure in mass production. The results reveal that the common practice of performing evaluations with fixed safety margins is non-effective and hence very dangerous, or is extremely conservative and thus costly. The application of stochastic simulation methods reduces the need for wide safety margins while simultaneously increasing the reliability of the process by incorporating uncertainty into the simulation
Authors: Bai Liu
Abstract: Based on Finite Element Analysis (FEA) module of Dynaform software, the paper made numerical simulation of a wheel hub’s stamping process in the method of elastic-plastic flow, pointed out the behavior of deformation of stamping process, predicted and prevented stamping defect such as crack in the process, and calculated the degree of resilience. Consequently three forming numerical simulation schemes have been designed respectively, more feasible process parameters has been achieved in comparison with the features of each scheme.
Authors: Pierre Antoine Dubos, Gwendoline Fleurier, Eric Hug
Abstract: Miniaturization of small metallic systems can lead to a softening of the mechanical behavior due to the reduction of scale. Size effects have been considerably studied recently for materials with various crystallographic structures. Under tensile conditions, thin specimen exhibit softer mechanical properties when the number of grains across thickness is lower than a critical number and this modification appears above a critical strain level. In this work, stamping tests were performed on five hundred micrometers in thickness sheets of hexagonal closed-packed cobalt. The results are compared with those obtained for face centered cubic copper and nickel. The influence of thickness over grain size ratio was studied for several proportional loadings linked to forming processes. Complex loadings were applied with 20 mm hemispherical punch and strain paths were checked with a 3D video extensometer. Hill criterion was systematically used to take into account the anisotropy of the samples. Our results revealed that the critical strain level for which the size effects appears is strongly sensitive to the stress triaxiality which, in turn, is closely dependent to the loading path.
Authors: Marius Ionuţ Rȋpanu, Gheorghe Nagîț, Vasile Merticaru, Marius Andrei Mihalache, Mihai Boca, Valerica Huşanu
Abstract: The quality of bearing cages is influenced by a variety of technological factors which depend on the material they are manufactured of, on the hydraulic press and on the punching-stamping die. The paper presents an optimized methodology introduced and developed for process quality analysis and monitoring activities involved in the stamping technology in order to manufacture roller bearing steel cages. The stamping technology presented in this case study is part of a larger industrial process of manufacturing steel window-type cages for spherical roller bearings with two rows of symmetrical rollers. This approach aims to improve a similar process quality analysis and monitoring activities which were previously developed on the basis of cause & effect analyses made upon the influence of qualitative and quantitative parameters involved in a quality and accurate stamping process.
Authors: Lin Zhou, Xiao Min Cheng
Abstract: Auto panel stamping is a complicated plastic deformation process with geometry nonlinear, material nonlinearity and numerous process parameters. The stamping process of a typical auto panel wheel wrap was studied by artificial intelligent optimization and physical experiment. The prediction model of object function was established using artificial neural network. In object function, blank-holder force, drawbead height and fillet radius were selected as the optimized variables and prevention of rupture was considered as the optimization objective. Process parameters optimization was performed with genetic algorithm. The optimized process parameters were used to guide die design and testing, and the result of wheel wrap stamping showed that the forming quality was obviously improved. So the process optimization based on artificial neural network and genetic algorithm is feasible and efficient for auto panel stamping.
Authors: Kang Kang Hu, Xiong Qi Peng, Jun Chen, Hong Sheng Lu, Jian Zhang
Abstract: The forming process simulation and springback prediction of an automobile body panel is implemented by using JSTAMP/LS-DYNA. Yoshida-Uemori model is selected to characterize the anisotropic material behavior of sheet metal during forming. Simulation predictions on spingback are compared with experiment measurements along with numerical results from other material models to demonstrate the effectiveness and accuracy of the Yoshida-Uemori model.
Authors: Ming Qing Wu
Abstract: Q235 stamping material thickness is 1 mm, with flip composite mould for production. Mold design using Pro/E, primarily for intensive convex, concave die, punching die design is analyzed, and based on Pro/E mold assembly.
Authors: Michela Simoncini, Lorenzo Panaccio, Archimede Forcellese
Abstract: The present investigation aims at studying post-welding forming operations of friction stir welded AA1050 aluminium thin sheets. A preliminary investigation has allowed to define the rotational and welding speed values leading to friction stir welded joints with high mechanical properties. Then, formability and elastic springback were evaluated using the hemispherical punch and bending tests, respectively. A microstructural investigation has allowed to relate the mechanical properties of joints to microstructure. Finally, the friction stir welded assemblies were subjected to air bending and stamping experiments in order to evaluate their attitude to undergo to sheet metal forming operations.
Authors: George Dinev, Marieta Yancheva, Vasilka Stancheva
Abstract: The article presents the results from the researches related to the designing and documentation of tooth wheels for stamping within a CAD medium. In order to increase the quality and the competiveness of the products, there have been offered methods related to the process of constructing. There have been developed 3D geometrical models as die forgings of tooth wheels obtained by volumetric, thermal stamping. These models are to be used for the preparation of working drawings of the die forgings. The results are useful for the purpose of establishment of creative constructive solutions and optimal production expenses which would meet the requirements of the market.
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