Papers by Keyword: Incremental Forming

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Authors: Yan Xu, Shuang Gao Li, Lin Gao
Abstract: Incremental forming of sheet metal is difficult to be simulated for its complicated 3D loading path. In this work, an acceptable approach to generate 3D loading path, called “virtual guiding model method” is accomplished. The method, which has the similar idea with the conventional copy mill, is based on FEM and the basic principle of kinematics. With the help of the method, multi-stage incremental forming of a drawing typed square cup was simulated in the FEM software-PAMSTAMP and experimented. Through measuring the thickness distribution the vertical edge of the cup, the most difference between them is less than 0.05mm, which is satisfied with engineering request, and the results shows that the 3D loading path generating method is one of the most effective way to realize the incremental forming simulation.
Authors: Jie Liu
Abstract: Sheet dieless digital forming is a new sheet metal dieless forming technology. This paper introduced the fundamentals of the Sheet dieless digital forming process. Based on the principle of “layered manufacture” in rapid prototype technology, this process resolves the intricate three-dimensional geometry information of the workpiece into a series of two-dimensional data, which can be used by an NC system to control a forming tool to make a curvilinear movement over the raw sheet metal layer by layer until the component wanted is formed. This paper introduced the Sheet dieless digital forming system and metal digital forming technology.
Authors: Liu Ru Zhou
Abstract: According to sine law, a vertical wall square box can’t be formed by NC incremental sheet metal forming process in a single process, rather, it must be formed in multi processes. A vertical wall square box can be considered to consist of corners and straight sides. Straight sides and corners affect each other and the effect is different in various square boxes. The effect depends on the ratio r/B of the corner radius r and straight side width B. The smaller r/B, the larger the effect of straight side on corner is. In this case, the deformation in the straight sides isn’t even, and the metal of the corner is compressed and gradually piled up. With the increase of r/B, the deformation becomes more uniform. The tool path with gradually reduced corner radius is adopted to overcome this question. A vertical wall square box with small corner radius is successfully formed.
Authors: Hu Zhu, Zhi Jun Liu, Jaegwan Kang
Abstract: A method of the digital simulation for the sheet metal CNC incremental forming was proposed based on the Z-map model. The tool extrusion movements were divided into two types according to the principle of sheet metal CNC incremental forming, i.e. vertical movement and horizontal movement. The vertical and horizontal swept volumes of the tool were built to intersect with the Z-map model of sheet metal respectively and the simulation models were generated. The thickness of deformed sheet metal was predicted and the thickness distribution chart was generated. The case studies show that the method can be applied to NC code verification, forming parameters optimization and formability prediction, moreover the system runs stably and reliably in the whole simulation process.
Authors: Amar Kumar Behera, Hans Vanhove, Bert Lauwers, Joost R. Duflou
Abstract: Previous studies have shown that feature detection and part segmentation are useful tools to generate compensated toolpaths for single point incremental forming leading to improvement in accuracy of manufactured parts. However, in most practical applications, features do not occur by themselves. Rather, they occur in combination with other features, and the presence of the neighbouring features influences the behaviour of the feature of interest. The final shape of the formed part depends on the interaction between the features. In this study, an attempt has been made to generate a complete taxonomy of common features relevant for incrementally formed parts. This taxonomy is then utilized to generate a matrix of feature interactions, and to classify them as feasible or not. From the subset of feasible feature interactions, a number of cases are analyzed to illustrate the effect of the interactions on the magnitude and nature of inaccuracies resulting in uncompensated parts. Strategies to use the knowledge of the interaction between these features to improve the accuracy of the manufactured parts are then discussed with the help of experimental case studies.
Authors: Amar Kumar Behera, Bert Lauwers, Joost R. Duflou
Abstract: Previous studies have shown that optimized tool paths based on behavior of individual features and feature interactions can be used to improve the accuracy of features in parts produced by single point incremental forming. These tool paths are generated with compensated CAD files of the part, which result from a prediction of deviations of individual features. However, in order to improve the accuracy of an entire part, it is important to systematically look at behavior of all the individual features and all feasible interactions between features. In this paper, the authors present a graph topology approach to integrating the effects of the behavior of all features present in a part. For any given part, a conceptual graph is constructed representing all the features and connecting them based on their spatial locations with conceptual relations. Next, all possible feature interactions based on the generated graph are analyzed, and the deviations due to the feasible interactions in an uncompensated test are predicted. Depending on the feature types and interactions present, a comprehensive strategy for accurate part manufacture is generated. This strategy may be composed of a selection of one or more complementary tool path strategies for compensating the anticipated deviations on the part. Case studies illustrating improvement in accuracy of parts produced by this technique are discussed next to justify the use of the graph based approach.
Authors: Hu Zhu, Wen Wen Lin, Jin Lan Bai
Abstract: The sheet metal CNC incremental forming is a flexible dieless forming technology that forms a sheet part by extruding the sheet metal point by point with the movement of forming tool along the forming path. The tool paths therefore have a great effect on the dimensional accuracy, surface quality and forming time. In this paper, an overview of the research status about the forming tool path generation for sheet metal CNC incremental forming is presented briefly.
Authors: Yao Teng Gong, Zhong Kai Zhang, Zhi Hong Jiang
Abstract: As a force being non-homogenous during incremental forming process, sheet metal tended to instability easily, then the deposition, wrinkle and fracture will be appearing concomitantly. If the vibration technique is introduced to the incremental forming process, its deformation mechanism will be changed, and forming quality is improved. Then some force equations are built by force analyzed for a element in local forming contact zone, some solutions of the force equations are obtained. With process parameters, mechanical performance parameters and vibra parameters given, stress curves are got. It is shown from simulation that the sheet metal stress has prominent variation with vibration,and forming-angle condition and frequency-condition should be met with vibration.
Authors: Xiao Bing Dang, Kai He, Shu Guo Wei, Jiu Hua Li, Ru Xu Du
Abstract: Based on the thought of incremental forming, a new kind of sheet metal bending process has been described and investigated in this article. The software of the control system for the specific machine is developed combining motion control card and servo motors. Both single point and multi-points bending are taken into consideration from experimental and finite element analysis. Curved sheet and hyperbolic sheet metal are examined through experiments to extend the application for more smoothed and complicated curved sheet metal. The effectiveness of the process to deal with complex curved sheet metal is shown by all the experiments.
Authors: Marek Tkocz, Franciszek Grosman
Abstract: The principle and the potential of an incremental bulk metal forming method is presented in the paper. It can be used for manufacturing of the specific aircraft integral panels in a form of ribbed parts with high surface/thickness ratio. A unique laboratory device has been developed to investigate the effect of process parameters on the material flow and the press load. It utilizes tooling consisting of working rolls, a die and a punch that is divided into a number of segments. The results of preliminary numerical simulations proved that the presented forming method offers significant advantages in comparison with conventional forging.
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