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The technical achievement described in this paper is to optimize all the variables in the extrusion of complex aluminum profiles using finite element (FE) simulation, statistical regression analysis, and analytical equations in a software platform to account for these variables and their interactions with each other as a group to achieve an ideal extrusion practice. This approach is done by repetitive computer simulations based on varying die modifications conducted through a CAD model of the die and then applying incremental changes to extrusion parameters (several die variables, extrusion speed, temperature, etc.) via an FE code and regression analysis in an optimization program that takes account of thousands of "tweaks" to the die configuration and extrusion process parameters. Computation time varies depending on extrusion complexity but is reasonable in terms of industrial practice. As has been determined in this paper, this optimization procedure was applied to the extrusion of two sample extrusions, a hollow tube and a complex rectangular hollow with screw bosses at its corners. In each case, die pressure was reduced and weld quality and the level of stress in the die were improved, while maintaining or increasing exit speed.

The additive manufacturing technology (AM) is considered to be the fourth-industrial revolution allowing to produce «near net» components almost without geometrical constraints. In contrast to conventional, subtractive technologies, additive manufacturing built up the component layer by layer starting from a 3D CAD model [1]. Due to the capabilities of the technology to face with high performance materials with added functionalities and increased complexity in geometrical designs, AM perfectly fits with the requirement of dies, tools and inserts. The AM technologies first developed in 1990s coming to the tools manufacturing some years later. In this context, the first applications were in low impact processes like plastic injection moulding but rapidly entered in metal working process applications like metal forming and die casting [2]. Nowadays, several metallic materials can be processed to full dense parts with outstanding properties, the most important at the industrial scale being represented by steels, aluminium and titanium alloys as well as Ni-based superalloys and CoCr [3,4].

The extrusion of aluminum alloys is a prcess able to manufacture high tolerances and high mechanical properties profiles. However, the main drawback of the process is that many objective functions need to be satisfied at the same time and many of these are potentially conflicting one each other. Example of conflicting objective functions are thre requirement fro high seam welds quality (in hollow profiles), an extended die lifetime and an high productivity. In order to solve the problem, the authors developed a comprehesive mutli-objective optimization of the extrusion process base on meta-models. The proposed procedure has been validated against two industrial profiles of a different complexity and a thrid case in now under investigation. Preliminary experimental analyses of the third case are presented.

Establishing numerical tools able to reliably analyze a manufacturing process takes a long time not only for their development, but also for proper validation through experimental trials in a wide range of processing conditions. In order to provide the extrusion industry and community with a place to discuss numerical techniques and to train users in FEM simulations, the ICEB – International Conference on Extrusion and Benchmark conference series was established in 2007.1 The aim of the conference was, and is still today, to merge the typical conference format (with presentation of papers from academia as well as industry) with a benchmark session where participants are asked to analyze a specific extrusion problem, the results of which are disclosed only during the conference.

© 2017 Elsevier B.V. An innovative process was developed for the leaching of niobium- and rare earth elements-bearing pyrochlores ores and the subsequent separation of Nb from the REE. Compared to the conventional Nb hydrometallurgical methods, the proposed leaching process is based on a triphasic system: H2SO4(aq)-SO2(g)-activated carbon/ore. The implementation of this leaching step allows the selective dissolution of the non-valuable phases while significantly reducing the H2SO4consumption. The results obtained in continuous operation, at the pilot scale, show a reduction of the sulfur consumption by 48% when compared to the classical H2SO4pasting-roasting process. The presence of activated carbon, at concentration as low as 0.4% (w/w), was found to considerably fasten the dissolution reactions and allows optimizing the SO2utilization to a nearly quantitative rate. The triphasic leaching also affords concentrating the Nb stream which decreases the energy consumption of the down-stream operations and especially for the subsequent Nb-REE-bearing pyrochlores roasting step. The process was optimized at the laboratory scale and then tested in continuous operation for 15 days at a flow of 15 kg h−1of dry equivalent of non-magnetic Nb-REE pyrochlore ore from the Gabonese Mabounié deposit and the equivalent of 8.25 kg h−1of H2SO4and 0.15 kg h−1of activated carbon.

The rupture of an intracranial Arteriovenous Malformation (AVM) in pregnancy is a rare occurrence, but may have fatal consequences. A link between AVM rupture and pregnancy has been proposed; it may be caused by the increased cardiac output or circulatory effects of the elevated estrogen levels. Surgical intervention for ruptured AVM during pregnancy could prevent rebleeding, and allow for determination of the delivery method based on the obstetrical indications. Cooperation between neurosurgeons, obstetricians, and anesthesiologists and sufficient information about the treatment strategy given to the patients are essential. Here, we report the case of a 27-weekpregnant woman who presented with a symptomatic ruptured cerebral AVM, treated by cesarean section followed surgical resection.

The tremendous variety of extruded profiles for automotive applications influences the die design and makes the optimization of the production cycle for a given shape one of trial and error. The profile requested by the final user is approved and is further transferred to the die maker with the profile drawing. The die is then loaded on the press for a trial run and correction. Good surface quality depends on specific knowledge of material flow, with harder alloys, customer requirements focuses mainly on the mechanical performance. Poor feedback between the extruder and die designer on extrusion performance is a common problem in the industry. Finite element method (FEM), neural networks, and fuzzy-logic algorithms are the only applications that could find a suitable application in the management of information transfer between extruders, die designers and profile users. Software engineering can also be used to investigate on some of the aspects of die mechanisms.

The 4th International Conference on Extrusion and Benchmark (ICEB 2011) will be held in Bologna, Italy from October 3-5, 2011. A large number of extruders, die makers, software houses, and researchers will gather at the event to discuss the core technology of light metal extrusion. More than 50 abstracts have been accepted on light alloy extrusion processing and the first day will be dedicated to these sessions. Papers will be also presented on ultra light alloys and new applications for extruded profiles. Process optimization and solutions to extrusion related issues will be analyzed thoroughly by several contributors. The second day of the event will be mainly dedicated to the benchmark experiment and participant results where the results of two monitored experiments will be discussed. The Scientific Benchmark will focus on the different strategies for balancing the material flow in porthole dies and its die design will deal with issues of hollow profile production, such as seam welding mechanism and material flow. The 4th International Conference on Extrusion and Benchmark (ICEB 2011) will be held in Bologna, Italy from October 3-5, 2011. A large number of extruders, die makers, software houses, and researchers will gather at the event to discuss the core technology of light metal extrusion. More than 50 abstracts have been accepted on light alloy extrusion processing and the first day will be dedicated to these sessions. Papers will be also presented on ultra light alloys and new applications for extruded profiles. Process optimization and solutions to extrusion related issues will be analyzed thoroughly by several contributors. The second day of the event will be mainly dedicated to the benchmark experiment and participant results where the results of two monitored experiments will be discussed. The Scientific Benchmark will focus on the different strategies for balancing the material flow in porthole dies and its die design will deal with issues of hollow profile production, such as seam welding mechanism and material flow.

During the hot-extrusion manufacturing process, a number of damage and deformation mechanisms act simultaneously to produce cumulative damage to the tools, thus causing the increasing deviations from the original geometry or the final breaking [1-3]. Due to the severe cyclic thermo-mechanical loads, mandrel, i.e. the part of the hollow die that defines the internal shape of the profile, is the most critical component in the extrusion of an hollow profile. Indeed, the high pressure generated during the process creates severe friction conditions that results in longitudinal tensile stress and significant bending stresses can arise in the bridges of the mandrel during extrusion. In addition to the mechanical cyclic load, the total loading/unloading time for the whole batch and the temperature that the die is exposed to are great enough to necessitate the consideration on the creep behaviour of the die material, particularly for hollow dies. Hence, the combination of dynamic, heavy loading and high temperature determines a hostile working condition for the mandrel that is normally designed on the basis of static loading at elevated temperatures on hot-work tool steels that are tempered to reach an adequate balance of hot hardness and toughness. Premature failure may occur after a certain number of loading and unloading cycles as a result of creep-fatigue interaction. The new technologies developed for aluminium extrusion aim to minimize the tool system-material flow interference and optimize the mechanical performance of the die that is related both to design and tool steel. Aim of the present work is to illustrate the steps followed to design an innovative experimental test purposely developed to investigate the deforming mechanisms of the AISI H11 tool steel in the creep-fatigue regime. The specimens replicate the geometry and the loading scheme of a mandrel on a smaller scale and are manufactured following the same working scheme. In such a way the test is able to account for realistic stress and strain distributions and superficial roughness of a real mandrel as well as to investigate different material and heat treatments.