Numerical Simulation of the Effect of Feedstock Shape on Continuous Extrusion Process

Abstract. Friction Stir Extrusion (FSE) is an innovative direct-recycling technology developed for metal machining chips. A rotating die is plunged into a cylindrical chamber containing the material to be recycled during the procedure. The die's stirring action causes strong bonding, enabling for the back extrusion of a full dense rod. One of the technology's major flaws is the process' discontinuity, which limits the volume of extrudes to the chamber's capacity. Based on the previous experience of some of the authors have designed a machine tool for continuous solid-state recycling of metal chips with the aims to overcome the limitations of the discontinuous process which makes it potentially appealing to industry. In this work, Friction Stir Extrusion process is defined, the set-up machines tool is presented, and the experimental findings of case studies are shown and analyzed. Finally, with the goal the mechanics of the FSE continuous process, a numerical model was created starting from the experimental results obtained by discontinuous process.

Numerical modeling and optimization of process parameters in continuous extrusion process through response surface methodology, artificial neural network & genetic algorithm

Polystyrene (PS) clay nanocomposites were synthesized and used to prepare foams in both batch and continuous extrusion process. It was found that the addition of a small amount of clay could greatly reduce cell size and increase cell density. Once exfoliated, the nanocomposite foam exhibits the highest cell density and the smallest cell size at the same particle concentration. Exfoliated microcellular nanocomposite foams with good surface quality was successfully produced using supercritical carbon dioxide.

The development of a long-span load-bearing reinforced-plastics roofing and walling unit

Metals are being replaced with high-performance and lightweight polymers, but their low thermal conductivity and poor electrostatic dissipative properties are significant problems. For the protection of sensitive electronic circuitry in automotive and aerospace parts, some device housing materials must provide electrostatic discharge and dissipate heat generated at higher rates as electronic circuits are increasingly miniaturized. Micro-texturing on the film surface can greatly enhance the heat dissipation area and was investigated in this study using low-cost graphite nanoplatelet (GNP)-filled LLDPE films. Micro-finned films (30 vol% GNP) having a 51 ± 10% larger heat-dissipation area were successfully produced using a continuous extrusion process. The through-thickness thermal conductivity of 30 vol% GNP-filled LLDPE was measured at 1.3 W/m·K, which represents a 200% improvement over that of pure LLDPE. For a GNP content of 30 vol%, the surface and volume electrical conductivity of the composite films also increased by 8 orders of magnitude (resistivity down from ≈1015 to 107 Ω·cm) and electrostatic decay time reduced to a below-resolution limit of 0.01 s, at par with military standard requirements. Thus, micro-fin textured GNP-LLDPE offers a unique combination of electrical and thermal transport desired for the protection of electronic encapsulation materials.

13 - Injection Molding Technology

This work was focused on the influence of the internal structure of natural rubber (NR)-based core-shell particles on the toughness of polystyrene (PS). Several emulsion polymerization processes were used to control the degree of grafting of the NR phase and the site of polymerization, which determines the final morphology of the prepared composite NR-based particles. PS subinclusions were introduced into the NR core in order to determine their influence on the deformation behaviour of PS. A continuous extrusion process was adapted for the direct feeding of the wet NR-based latexes into the molten PS matrix. Impact testing indicated that core-shell particles based on NR containing a large number of small crosslinked PS subinclusions toughened PS most effectively. A very effective toughening agent is obtained if a hard shell of 25 wt% crosslinked PMMA surrounds the composite rubber particle. Grafting of NR chains during the subinclusion synthesis has to be avoided since a high rubber particle modulus is detrimental for craze nucleation in PS. From the fracture surface morphology the craze nucleating and stabilizing efficiency of composite NR particles having different morphologies or grafting degrees could be deduced.

In this paper, a novel 3D printing process for reinforced concrete structures called Additive Manufacturing of Reinforced Concrete (AMoRC) is proposed. The process consists of a continuous concrete extrusion process and an intermittent stud welding process, both carried out by a robotic arm respectively. The welding robot runs ahead of the concrete extrusion robot and produces the spatial reinforcement mesh from prefabricated reinforcing bar segments. A novel fork-shaped print head with four adjustable nozzles allows for concrete extrusion around the reinforcement with different diameters. By joining segmented rebars of limited length to a reinforcement mesh in the AMoRC process, the consumption of energy and time can drastically be reduced compared to shape welding. The length of the joined rebars can be adapted to the component geometry and the extrusion speed. The bar segments to be joined are kept ready in a magazine belonging to the print head, which enables the feeding of bars with different diameters to arrange a load-efficient and economical reinforcement mesh. The preliminary testing of the additively fabricated reinforced concrete components is also implemented to characterize the structural behaviour of those 3D-printed composite specimens. In the initial phase, the reinforcement installation was performed manually until the second robot will be added to the process and experiments were done to characterize the printed structures. The pull-out test is used to investigate the bonding behavior between reinforcement and printed concrete. The four-point bending test is also utilized to study the mechanical behavior of the printed reinforced concrete specimen in a larger scale.

Food Emulsions in Extruded Glassy Materials

Smart textiles provide a significant technological advancement, but their development must balance traditional textile properties with electronic features. To address this challenge, this study introduces a flexible, electrically conductive composite material that can be fabricated using a continuous bi-component extrusion process, making it ideal for sensor electrodes. The primary aim was to create a composite for the filament's core, combining multi-walled carbon nanotubes (MWCNTs), polypropylene (PP), and thermoplastic elastomer (TPE), optimised for conductivity and flexibility. This blend, suitable for bi-component extrusion processes, exemplifies the role of advanced materials in combining electrical conductivity, mechanical flexibility, and processability, which are essential for wearable technology. The composite optimisation balanced MWCNT (2.5, 5, 7.5, and 10 wt.%) and TPE (0, 25, and 50 wt.%) in a PP matrix. There was a significant decrease in electrical resistivity between 2.5 and 5 wt.% MWCNT, with electrical resistivity ranging from (7.64 ± 4.03)104 to (1.15 ± 0.10)10-1 Ω·m. Combining the composite with 25 wt.% TPE improved the flexibility, while with 50 wt.% TPE decreased tensile strength and hindered the masterbatch pelletising process. The final stage involved laminating the composite filament electrodes, with a 5 wt.% MWCNT/PP/(25 wt.% TPE) core and a TPE sheath, into a textile triboelectric impact detection sensor. This sensor, responding to contact and separation, produced an output voltage of approximately 5 V peak-to-peak per filament and 15 V peak-to-peak with five filaments under a 100 N force over 78.54 cm2. This preliminary study demonstrates an innovative approach to enhance the flexibility of conductive materials for smart textile applications, enabling the development of triboelectric sensor electrodes with potential applications in impact detection, fall monitoring, and motion tracking.

The study covers technology features of making pressed items of non-ferrous metals by Conform continuous forming. The analysis of pressing equipment designs identified a disadvantage typical for many Conform units – the lack of connection between the system for securing the fixed part of the split container (shoe) and the impeller shaft. Therefore, it is impossible to ensure a controlled gap between the shoe and the groove bottom during the operation, which results in unstable bar stock feeding to the die. The paper aimed at the development of a new shoe attachment system to ensure a steady flow of continuous metal extrusion process. This provides for forming a rigid and strong connection between the shoe and the impeller shaft using the system of levers and rods. An upgraded die assembly was proposed to solve this problem. The drive components and working parts of the pilot Conform unit were designed based on power calculations made for extrusion of aluminum and copper alloys using the formulas provided in the technical literature. The obtained results were used for strength calculations of die assembly parts following the known methods. The practical use of the design proposed in the paper will provide new opportunities to make pressed steel items of non-ferrous metals with a consistently high level of properties.

Pollution burdens associated with load/assemble/pack of an ap based MK-66 PIP motor by continuous and batch processing

Abstract

Continuous extrusion is an advanced process for manufacturing copper strip. Its successfully industrial application is to manufacture copper strip. Based on finite element method (FEM), using the Deform-3D software, this paper simulates continuous extrusion forming process for copper strip, and analyzes the effect of different feedstock diameter on metal flowing temperature, effective stress, velocity, rotating torque. The results show that: feedstock diameter greatly affects the continuous extrusion forming process; Under the same rotating speed, as feedstock diameter increases, the metal flowing velocity increases. It is benefit to enhance the productivity; As feedstock diameter increases, the temperature of the billet and tooling increases, and the torque of extrusion wheel increases, which leads to tooling wear seriously.

Mitochondria are highly dynamic organelles, the location, size and distribution of which are controlled by a family of proteins that modulate mitochondrial fusion and fission. Recent evidence indicates that mitochondrial morphology is crucial for cell physiology, as changes in mitochondrial shape have been linked to neurodegeneration, calcium signalling, lifespan and cell death. Because immune cells contain few mitochondria, these organelles have been considered to have only a marginal role in this physiological context-which is conversely well characterized from the point of view of signalling. Nevertheless, accumulating evidence shows that mitochondrial dynamics have an impact on the migration and activation of immune cells and on the innate immune response. Here, we discuss the roles of mitochondrial dynamics in cell pathophysiology and consider how studying dynamics in the context of the immune system could increase our knowledge about the role of dynamics in key signalling cascades.