Papers by Keyword: Extrusion

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Authors: Francesco Gagliardi, I. Alfaro, Luigino Filice, E. Cueto
Abstract: The conventional tube extrusion process has been substituted by porthole die extrusion due to relevant advantages in terms of productivity and quality. However, the porthole die has a complex geometry to be effectively designed; consequently, several studies can be found out in the technical literature based on experimental and finite element analyses of the process. From this point of view, while the experimental investigations entail cost and time increasing, due to the die building complexity, finite element techniques present some drawbacks such as the difficulty to simulate material joining and the loss of accuracy due to the heavy mesh distortion and related remeshing. Therefore, the introduction of new numerical techniques for the analyses of this process could have positive effects. In this paper, the Natural Element Method (NEM) together to the alpha shapes and some extra numerical procedures are used in the simulation of tube extrusion, focusing the attention on the simulation of the welding line in a fully 3D analysis. The obtained results are compared with the finite element and experimental ones, measuring the accuracy of the proposed methodology.
Authors: Luo Xing Li, Jia Zhou, X. He, Jie Zhou, Jurek Duczczyk
Abstract: The present case study addressed a practical problem of wall thickness attenuation during extrusion to produce a complex thin-walled hollow magnesium profile. A HyperWorks FEM software package was employed to aid in identifying the causes for the wall thickness attenuation. Recommendations were made to adjust the interspacing between the mandrels and the height of the welding chamber. The modified dies yielded much improved results in terms of velocity and hydrostatic pressure uniformity. The wall thickness of the extrudate predicted using FEM simulation was very close to experimental measurements. The case study demonstrated the feasibility of using FEM simulation as a useful tool to solve industrial problems encountered in the production of complex profiles.
Authors: Ji Yong Yao, D.A. Graham, Malcolm J. Couper
Authors: Luigino Filice, Francesco Gagliardi, Fabrizio Micari
Abstract: Nowadays, many researchers are involved in studies aimed to the explanation of some peculiar aspects regarding manufacturing processes. In this paper, an experimental campaign was carried out in order to reproduce tube extrusion starting from a cylindrical billet. In particular, the development of a proper equipment is presented: the aim was to measure both the total load, by using the testing machine load cell, and the local pressure value on the porthole. The latter task was carried out performing a proper system based on the use of a small load-cell. The tube was extruded with a good surface quality and the external area does not show any welding line evidence. Pure Lead was used for the experimental analysis; this material was chosen due to its high ductility which allows to carry out the process at room temperature. The material was characterized by compression tests at different strain rates and the obtained material law was used to perform a numerical analysis using SFTC Deform 3D numerical code. The Numerical analysis was carried out to show both the advantages and drawbacks of the modern FE codes when extrusion processes are investigated.
Authors: Aleksandra J. Botten, A.S. Burbidge, S. Blackburn
Authors: Elizabeth C. Kolos, Andrew Ruys, Greg J. Roger
Authors: Seyed A. Tabatabei, M.K. Besharati Givi, Karen Abrinia, Peyman Karami, V. Zal, S. Mirjavadi
Abstract: Die shape plays a key role in extrusion process through widely affects on the extrusion pressure and product quality. Therefore, prediction of the optimal die shape is the main objective for an effective extrusion process. In this study, the notion of Equi-Potential Lines (EPLs) was applied to 3D-die designing in extrusion process for the first time. To implement the analogy in the extrusion, the initial and final shapes were considered and two different potentials were assigned to them, and then EPLs were drawn between two shapes that show the minimum work path between the entry and exit cross sections. The drawn EPLs were connected to build up a 3D-die. The effectiveness of the proposed method was examined experimentally, by comparing the results between the designed die and the linear die (with the linear curve for the deformation zone). It was found that there was acceptable reduction in extrusion pressure for the designed die.
Authors: Ole Runar Myhr, Rune Østhus, Trond Furu
Abstract: The present paper describes a novel methodology for optimization of product properties and production costs in fabrication of aluminium alloys. The main idea is to represent each operation along the process chain by predictive tools, which include material-, mechanical-, cost-and logistics models. An optimisation tool is used to collect the simulation models into a common software environment, which allows fully automatic simulations to be carried out. When this coupling is established, the models are run in sequence using different types of optimisation strategies. The methodology has been applied for optimisation of strength, grain structure and costs of 6xxx series aluminium extrusions. The results indicate that the present methodology is sufficiently relevant and comprehensive to be used as a tool in fabrication of various aluminium products, for instance in optimisation of end-user properties and production costs of extruded, rolled or foundry based alloys.
Authors: Akshaya Kumar Rout, Kali Pada Maity, Sushant Kumar Rath
Abstract: The die profile plays an important role in reduction of extrusion load, evolution of uniform micro-structure and overall improvement of surface integrity of extruded product. In the present investigation, a numerical analysis has been carried out for extrusion through cosine die profile using DEFORM software for plane strain deformation using rigid plastic material. The extrusion load has been predicted. The effective stress, strain, strain rate and velocity distribution have been determined. It is proposed to investigate the evolution of uniform microstructure and the effect of strain hardening in the extrusion process in future work.
Authors: Manabu Gotoh, Minoru Yamashita, Kazuhide Wakasugi
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