Optimum Extrusion Research Articles

Analytical study of some kinematics variables for the last steps in the javelin event and their relationship with performance

Kinematics is one of the branches of biomechanics used in the field of sports, and it is one of the important tools that aid in the diagnosis of faults and virtues of the technical performance of the movement. javelin. This effectively goes through multiple stages the require continuous biomechanical evaluation in order to accomplish advance achievement. This study's primary objective was to determine the values of some kinematic variables of the last three steps of the javelin throw by senior throwers from Erbil provence clubs. The the research population consists of senior throwers in Erbil governarate clubs who participated in the Erbil competition numbered (12) individuals, furthermore, the sample of (5) players intentionally selected from population. The results show that there is a correlation between the length of the second-to-last and last step in addition to correlation between vertical velocity in the third step with javalin achievement. The researchers concluded that the optimal extrusion angle (45 degrees) is not optimal for all events; although the javelin is a projectile, a 45-degree angle is not commonly used in the javelin (angle younger had a correlation with the best achievement of the angle 45).

Effects of different processing methods on phenolic compounds in flaxseed meal

This study examined effects of different processing methods on phenolic compounds in flaxseed meal. The optimal SE treatment was 1.0 MPa for 3 min, and the contents of total flavonoids and phenolic acid were 2.26 times and 1.63 times of the control group, respectively. Notably, erucic acid increased 85.76 %. Optimal extrusion conditions (15 % moisture content, 140 °C, 29 hz) led to the presence of rutin and a 2.81 times increase in protocatechuic acid content over the control. Fermenting with 3 % Bacillus subtilis for 4 days yielded gallic acid in bound form and vanillic acid in free form, with protocatechuic acid increasing 40.65 % compared to the control. Among all the treatments, extrusion produced the highest levels of phenolic compounds in flaxseed meal. Each treatment significantly increased the open ring isomer ester phenol (SDG) compared to the control. Overall, various processing methods impacted the phenolic content and composition in flaxseed meal differently.

Interaction between material and process parameters during 3D concrete extrusion process

Extrusion of cement-based materials in additive manufacturing is influenced by a complex interaction of various material and process parameters. This study aims to investigate the impact of rheological properties and printing parameters on the extrudability of cement-based materials as well as the interaction between rheological properties of print materials and extrusion speed, as a key printing process parameter. 20 different print materials with diverse rheological properties were extruded at 10 different extrusion speeds. The effect of material parameters (i.e. rheological properties) and process parameters (i.e., extrusion speed) and their interaction during the extrusion process were evaluated using filament continuity, conformity and consistency. At a constant printing speed, a higher yield stress adversely impacted filament continuity in mixtures with a yield stress of over 260 Pa, whereas viscosity showed minimal influence on filament quality within the tested range of the rheological properties. The results of this study highlighted a significant correlation between material and process parameters and that adapting process parameters to variations in material properties is crucial for meeting printing criteria. The filament consistency of the mixtures with high yield stress was more sensitive to change in the extrusion speed than that of mixtures with low yield stress. An opposite trend, however, was observed for filament conformity where low yield stress mixtures showed a higher sensitivity to the extrusion speed. A procedure was suggested and applied to determine the optimum extrusion speed. Optimal extrusion speeds enabled printing mixtures with a broader spectrum of rheological properties with an acceptable visual quality, filament conformity and consistency requirements. With extrusion speed adjustment, the extrudability window was expanded from dynamic yield stress of 108–126 Pa to 108–263 Pa and plastic viscosity of 8.2–12.3 Pa.s to 5.1–16.4 Pa.s.

Optimization and Validation of Extrusion Process Parameters for the Sensory Characteristics of Extruded Aerial Yam and Soybean Flour Blends

The aim of this study was to optimize and validate the extrusion process parameters (barrel temperature, screw speed, and feed moisture) for the sensory properties (texture, taste, appearance, and aroma) of extrudates made from blends of soybean and aerial yam flours. Five levels of barrel temperature (95, 100, 105, 110, and 115 °C), screw speed (85, 100, 115, 130, and 145 rpm), and feed moisture (31, 33, 35, 37, and 39%) were employed in 20 runs of the response surface methodology (RSM), which was based on the Box-Behnken design with three variables. A single-screw extruder at the laboratory scale was used to carry out the extrusion procedure. A high regression coefficient (R2 ≥ 0.9) indicates that the models are useful for navigating the design space. Numerical optimization results indicated that the optimal extrusion process parameters - barrel temperature of 114.12 °C, screw speed of 100.56 rpm, and feed moisture of 38.02% - produced extrudates with optimal sensory property scores of 5.34 for texture, 4.91 for taste, 6.97 for appearance, and 5.80 for aroma, with a desirability of 0.943. The correlation between the predicted and experimental values yielded a high coefficient of determination, indicating a good correlation. The “Fit and Diagnostic Case” statistics showed a low range of deviations between the predicted and observed values for the sensory characteristics. Therefore, the generated quadratic model accurately predicts the sensory characteristics of aerial yam-soybean flour blends and is thus validated.

Effect of Hot Extrusion on Microstructure, Texture, and Mechanical Properties of Mg-Zn-Mn-0.5Ca Alloy

This paper investigates the microstructure, texture, and mechanical properties of the Mg-4Zn-1Mn-0.5Ca alloy subjected to hot extrusion under varying conditions of temperature (260 °C, 300 °C, 340 °C) and extrusion speed (0.01 mm/s, 0.1 mm/s, 1 mm/s). The primary objective is to determine the optimal extrusion parameters within the selected experimental range for achieving superior mechanical properties. The results indicate that, when extruded at a constant speed of 0.1 mm/s, the alloy exhibits optimal performance at 340 °C, with a yield strength of 202 MPa, ultimate tensile strength (UTS) of 306 MPa, and elongation at fracture of 18.9%. A decrease in extrusion temperature leads to an increase in yield strength but a reduction in ductility. Specifically, the UTS reaches its peak at 342 MPa at 300 °C, while it drops slightly to 329 MPa at 260 °C. The final results show that the comprehensive mechanical properties of the Mg-4Zn-1Mn-0.5Ca alloy obtained by hot extrusion treatment with an extrusion temperature of 300 °C and extrusion speed of 0.1 mm/s are the best and can effectively improve the mechanical properties of the alloy and provide a good choice for the preparation of other biodegradable magnesium alloy products.

Automated Optimum Extrusion Die Design and Profile Quality Control Based on Simulation

The paper presents the experience of development and implementation of an integrated approach of extrusion simulation with the automated design of the dies as a new way to speed up the technology development and its optimisation based on the QForm UK Extrusion simulation program and QForm Extrusion Die Designer (QExDD) design system. Bearing and prechamber optimisation types are considered for the porthole design. Welding quality and possible streaking lines in the profile are analysed for the tool construction with optimised prechamber contour.

Optimization of Glass-Powder-Reinforced Recycled High-Density Polyethylene (rHDPE) Filament for Additive Manufacturing: Transforming Bottle Caps into Sound-Absorbing Material.

Additive manufacturing presents promising potential as a sustainable processing technology, notably through integrating post-consumer recycled polymers into production. This study investigated the recycling of high-density polyethylene (rHDPE) into 3D printing filament, achieved by the following optimal extrusion parameters: 180 °C temperature, 7 rpm speed, and 10% glass powder addition. The properties of the developed rHDPE filament were compared with those of commonly used FDM filaments such as acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) to benchmark the performance of rHDPE against well-established materials in the 3D printing industry, providing a practical perspective for potential users. The resulting filament boasted an average tensile strength of 25.52 MPa, slightly exceeding ABS (25.41 MPa) and comparable to PLA (28.55 MPa). Despite diameter fluctuations, the filament proved usable in 3D printing. Mechanical tests compared the rHPDE filament 3D printed objects with ABS and PLA, showing lower strength but exceptional ductility and flexibility, along with superior sound absorption. A life cycle analysis underscored the sustainability advantages of rHDPE, reducing environmental impact compared to conventional disposal methods. While rHDPE falls behind in mechanical strength against virgin filaments, its unique attributes and sustainability position it as a valuable option for 3D printing, showcasing recycled materials' potential in sustainable innovation.

Advancing sustainable construction: Terracotta component development through extrusion-based 3d printing with local clay

This study examines the use of 3D printing technology in construction, specifically the use of local clay as the primary material for developing Terracotta components. The results demonstrate the feasibility and high print quality achievable with clay, establishing it as a viable material for 3D printing in construction. The analysis of physical properties, such as shrinkage, density, and water absorption, provides valuable insights. Thermal conductivity, also examined, contributes to a comprehensive understanding of material performance. The article identifies the optimal extrusion parameters for terracotta components. The evaluations show that the water absorption rates are within standards, and the density variation ranges from 1420 to 1466 kg/m³. Additionally, there is a direct correlation between thermal conductivity and density. The compressive strengths are diverse, ranging from 18 MPa to 33 MPa. While modulus of elasticity provides essential quantitative data for understanding the mechanical behavior of printed samples when subjected to various stresses. The internal structure significantly influences compression resistance in 3D printed bricks, emphasizing its importance in design. This research highlights the potential of 3D printing, specifically with clay, in sustainable construction. It encourages further exploration of its practical applications in the industry.

Optimization of germinated cowpea flour ratios and extrusion conditions on the nutritional composition and sensory quality of Ethiopian emmer wheat-based extruded porridge

Childhood malnutrition is a major problem in developing countries, particularly in Ethiopia. This study aimed to create nutritious emmer wheat and cowpea extruded porridge with optimal macronutrient levels and sensory quality. Utilizing Design-Expert software, the effects of cowpea blending ratios (10–25 %), barrel temperatures (80–120 °C), and feed moisture content (22–26 %) were analyzed using a three-factor, three-level Box-Behnken design. Significant impacts on nutritional characteristics were observed, leading to the identification of optimal extrusion conditions (cowpea blend: 20.17 %, moisture content: 25.91 %, barrel temperature: 117.20 °C). Blending emmer wheat with cowpea flour significantly enhanced the porridge's color, taste, and aroma. The highest color intensity (4.36 %) was at 10 % cowpea and 22 % moisture processed at 100 °C. The best taste (4.41 %) was with 25 % cowpea and 22 % moisture at 100 °C, while the highest aroma was in blends with 10 % and 25 % cowpea at 100 °C. The control had the best mouthfeel (4.36 %), but a blend with 25 % cowpea, 24 % moisture, and 80 °C barrel temperature had the highest overall acceptability (4.31 %). The study highlighted the potential of these protein-rich porridge products to address protein-energy malnutrition, particularly in Ethiopia, by introducing awareness about the unique nutritional composition of Ethiopian emmer wheat and underutilized cowpea, thus creating a new market for nutritious food options.

Efficient adsorptive removal of low concentration fluoride ions from water by cellulose beads with trapped CeO2 nanoparticles

The high electronegativity and solubility of fluoride ions (F-) in water at low concentrations pose challenges for their treatment and recovery. To effectively adsorb F-, cellulose beads with trapped CeO2 nanoparticles (CeO2@CBs) were fabricated from a NaOH/urea aqueous solution by the optimal extrusion dropping technology. The CeO2@CBs exhibited a maximum removal efficiency of 99.15 % for 10.0 mg L−1 F- at 45°C, pH=3.0 and an adsorbent dose of 1.0 g. The CeO2@CBs were characterized using SEM-EDS, FT-IR, XRD, and XPS. These findings demonstrate that CeO2 nanoparticles were uniformly entrapped in cellulose beads and reveal that the removal mechanism involves anionic exchange and electrostatic attractions between protonated hydroxyl on CeO2@CBs surface and F-. The results show that the anion competition sequence that affects the F- adsorption efficiency was Cl−<NO3−<SO42−<PO43−. CeO2@CBs were directly packed into columns, exhibiting exceptional adsorption efficacy and remarkable stability in column experiments. Even after three desorption cycles, the adsorption performance remained above 95 %. Because the designed CeO2@CBs have a simple preparation process, high adsorption efficiency and environmental friendliness, they can provide valuable insights for designing new adsorbents and removing F- from aqueous solutions.

Wear resistance of extruder parts in the production of polymer nanomodified products

Extrusion equipment is widely used in the production of polymer materials. One of the urgent questions that arises when studying the processes of obtaining polymer products by the extrusion method is the question of studying abrasive wear, which may depend on the efficiency of the equipment, the duration and reliability of its work. In the context of abrasive wear, the process that needs attention is the extrusion of polymer materials with carbon nanotubes. The purpose of this work is to develop a numerical method for determining the evolution of abrasive wear of the equipment of the extruder working area in the process of processing nanomodified polymer granules and determining the life cycle of this equipment with in order to increase the parameters of their durability. The specific objectives of the study include: 1) Determination of the influence of the content of CNTs in PVC on the rate of wear of the steel surface of the extruder; 2) Analysis of the dependence between friction and the content of CNTs in the polymer composite; 3) Establishing optimal extrusion conditions to minimize abrasive wear of the steel surface; 4) Comparison of simulation results with experimental data to check the reliability of the model. The work is aimed at understanding the processes that occur during the extrusion of nanocomposites and their impact on the wear resistance of equipment materials, which can contribute to the improvement of technological processes and ensure longer and more efficient operation of extruders in production conditions. It has been established that the processes of extrusion processing of polymer nanoreinforced composites can be effectively studied by developing and implementing numerical models that take into account the interaction of all physical and mechanical parameters of a representative volume of the contact zone of the equipment with the polymer and the nanotube with the adhesive layer. In this work, a model for determining the physical and mechanical properties of the interface layer between the CNT and the polymer array is constructed and implemented. The technique for determining the properties of the nanotube-polymer interface is integrated into the APROKS system for analyzing the stress-strain state of nanomodified polymer materials. Based on a multilayer isoparametric FE, a series of numerical experiments were carried out to simulate the process of abrasive wear of the material of equipment elements in the extruder working area. The possibility of a detailed study of the processes of nonlinear contact interaction of nanotubes with an interface layer with equipment elements of the extruder working area based on multilayer FE has been confirmed. Diagrams were obtained that determine the service life of equipment in the working area of the extruder depending on the volume concentration of carbon nanotubes in the polymer at different levels of operating pressure in the “nanotube – polymer – equipment” contact system. It is advisable to use the proposed methodology in the development of information support systems for the life cycle of operation of equipment in the working area of extruders intended for the production of nanomodified polymer products.

Printing GelMA bioinks: a strategy for buildingin vitromodel to study nanoparticle-based minocycline release and cellular protection under oxidative stress.

Owing to its thermoresponsive and photocrosslinking characteristics, gelatin methacryloyl (GelMA)-based biomaterials have gained widespread usage as a novel and promising bioink for three-dimensional bioprinting and diverse biomedical applications. However, the flow behaviors of GelMA during the sol-gel transition, which are dependent on time and temperature, present significant challenges in printing thick scaffolds while maintaining high printability and cell viability. Moreover, the tunable properties and photocrosslinking capabilities of GelMA underscore its potential for localized drug delivery applications. Previous research has demonstrated the successful incorporation of minocycline (MH) into GelMA scaffolds for therapeutic applications. However, achieving a prolonged and sustained release of concentrated MH remains a challenge, primarily due to its small molecular size. The primary aim of this study is to investigate an optimal extrusion printing method for GelMA bioink in extrusion bioprinting, emphasizing its flow behaviors that are influenced by time and temperature. Additionally, this research seeks to explore the potential of GelMA bioink as a carrier for the sustained release of MH, specifically targeting cellular protection against oxidative stress. The material properties of GelMA were assessed and further optimization of the printing process was conducted considering both printability and cell survival. To achieve sustained drug release within GelMA, the study employed a mechanism using metal ion mediation to facilitate the interaction between MH, dextran sulfate (DS), and magnesium, leading to the formation of nanoparticle complexes (MH-DS). Furthermore, a GelMA-basedin vitromodel was developed in order to investigate the cellular protective properties of MH against oxidative stress. The experimental results revealed that the printability and cell viability of GelMA are significantly influenced by the printing duration, nozzle temperature, and GelMA concentrations. Optimal printing conditions were identified based on a thorough assessment of both printability and cell viability. Scaffolds printed under these optimal conditions exhibited exceptional printability and sustained high cell viability. Notably, it was found that lower GelMA concentrations reduced the initial burst release of MH from the MH-dextran sulfate (MH-DS) complexes, thus favoring more controlled, sustained release profiles. Additionally, MH released under these conditions significantly enhanced fibroblast viability in anin vitromodel simulating oxidative stress.

Effects of different extrusion temperatures on the physicochemical properties, edible quality and digestive attributes of multigrain reconstituted rice.

Multigrain reconstituted rice, as a nutritious and convenient staple, holds considerable promise for the food industry. Furthermore, highland barley, corn, and other coarse cereals are distinguished by their low glycemic index (GI), rendering them effective in mitigating postprandial blood glucose levels, thereby underscoring their beneficial physiological impact. This study investigated the impact of extrusion temperature on the physicochemical properties, edible quality, and digestibility of multigrain reconstituted rice. The morphology revealed that starch particles that are not fully gelatinized in multigrain reconstituted rice are observed at an extrusion temperature range of 60 °C-90 °C. As the extrusion temperature increased, the degree of gelatinization (DG) increased, while the contents of water, protein, total starch, and amylopectin decreased substantially. Concurrently, the relative crystallinity, orderliness of starch, and heat absorption enthalpy (ΔH) decreased significantly, and water absorption (WAI) and water solubility (WSI) increased markedly. Regarding edible quality, sensory evaluation displayed an initial increase followed by a decrease. In terms of digestibility, the estimated glycemic index (eGI) increased from 61.10 to 70.81, and the GI increased from 60.41 to 75.33. In addition, the DG was significantly correlated with both eGI (r = 0.886**) and GI (r = 0.947**). The results indicated that the ideal extrusion temperature for multigrain reconstituted rice was 90 °C. The findings underscored the pivotal role of optimal extrusion temperatures in the production of multigrain reconstituted rice, which features low GI and high nutritional quality.

Manufacture of Biomimetic Auricular Surgical Implants Using 3D Printed High Density Polyethylene Microfibers

AbstractThis study demonstrates a new approach to manufacturing biomimetic auricular surgical implants using melt electrowriting (MEW) technology to fabricate microfiber high‐density polyethylene (HDPE) scaffolds. An emerging filament‐driven printhead and MEW printer, termed the “MEWron”, is used to enable precise control over the material extrusion process and fiber formation. By predicting the optimal extrusion conditions, continuous and uninterrupted fiber production is achieved, enabling further optimization of filament‐driven MEW fibers with a diameter of 60.5 ± 2.6 µm. As a case study, an application of microfiber HDPE fabrication is selected that comprised the design and fabrication of personalized auricular (ear) surgical implants, specifically tailored to match the unique morphology of individual patients. Patient‐specific implant models matched to the natural shape and structure of the human ear are successfully fabricated. Furthermore, the manufactured implants exhibit excellent mechanical properties, offering a 13‐fold increase in tensile stiffness compared to MEW PCL scaffolds. Overall, this research demonstrates the feasibility and potential of MEW‐based HDPE implants as a promising alternative to traditional auricular reconstruction methods, offering an alternative avenue for improved patient outcomes and enhanced aesthetic results.

Effects of Process Variables on the Physicochemical, Textural, and Structural Properties of an Isolated Pea Protein-Based High-Moisture Meat Analog.

This study investigated the optimal extrusion conditions required to produce an isolated pea protein (IPP)-based meat analog. High-moisture extrusion cooking (HMEC) was performed. The effects of the moisture content (55 and 60%), barrel temperature (165 and 175 °C), and screw speed (150 and 200 rpm) on the physicochemical, textural, and structural properties of the high-moisture meat analog (HMMA) were determined. The results showed that the moisture content had a significant effect (p < 0.05) on the physicochemical and textural properties of the HMMA. A lower moisture content had significant impact (p < 0.05) on enhancing the texturization of the HMMA and the formation of fibrous structures, thereby increasing the texture profile analysis (TPA) and cutting strength of the HMMA. Protein denaturation during HMEC resulted in a lower protein solubility of the meat analog than the raw material. The content of β-sheets and β-turns in the meat analogs were higher than that in the raw material, while the content of random coils and α-helices is inversely proportional. The process variables had no significant (p > 0.05) effect on the secondary structures. In conclusion, the moisture content is the most important factor affecting the properties of HMMAs. The extrusion process variables for HMMAs are a moisture content of 55%, a barrel temperature of 175 °C, and a screw speed of 200 rpm.

A multi-reservoir extruder for time-resolved serial protein crystallography and compound screening at X-ray free-electron lasers

Serial crystallography at X-ray free-electron lasers (XFELs) permits the determination of radiation-damage free static as well as time-resolved protein structures at room temperature. Efficient sample delivery is a key factor for such experiments. Here, we describe a multi-reservoir, high viscosity extruder as a step towards automation of sample delivery at XFELs. Compared to a standard single extruder, sample exchange time was halved and the workload of users was greatly reduced. In-built temperature control of samples facilitated optimal extrusion and supported sample stability. After commissioning the device with lysozyme crystals, we collected time-resolved data using crystals of a membrane-bound, light-driven sodium pump. Static data were also collected from the soluble protein tubulin that was soaked with a series of small molecule drugs. Using these data, we identify low occupancy (as little as 30%) ligands using a minimal amount of data from a serial crystallography experiment, a result that could be exploited for structure-based drug design.

The effect of extrusion condition and blend proportion on the physicochemical and sensory attributes of teff-soybean composite flour gluten free extrudates

The effects of soybean-to-teff ratio (SB), feed moisture content (FM) and barrel temperature (BT) on physico-chemical properties and sensory attributes of extruded product from teff-soybean flour blend was studied. Increase in BT resulted in increase in expansion ratio(ER), water absorption index (WAI), and water solubility index (WSI) whereas the bulk density (BD) and hardness decreased with increase in BT. Increase in the proportion of SB resulted in increased BD, hardness, and reduced water solubility index (WSI) and sensory scores. Three principal components explained 89.1 % of the variations where the first (PC1), the second (PC2) and the third (PC3) principal components explained 62.4, 20.2 and 6.5 % of the variations respectively. BD, WAI and Hardness are strongly and positively associated with each other whereas they are negatively associated with WSI, crispiness, Specific length (Lsp) and ER. Graphical optimization gave best results for BT between 128 and 137 °C and SB proportion between 2 and 7.3 % where the FM is fixed at 10 %. Besides, BT of 135 °C to137 °C, FM of 10–12 % when the SB proportion is fixed at 7.5 % gave optimal product quality. The numerical optimization resulted in optimal extrusion conditions for optimal product quality were BT of 135 °C, FM of 10 % and SB proportion of 5 % with a desirability value of 0.875. The results revealed that SB can be incorporated up to 7.5 % to obtain an acceptable product. Therefore it is possible to produce gluten-free extruded snack by blending teff and soybean flour.

Tensile Properties of 3D Printed Recycled PLA Filament: A Detailed Study on Filament Fabrication Parameters

Polylactic acid (PLA), a biodegradable and biocompatible thermoplastic commonly utilized in 3D Printing filaments, undergoes changes in properties upon recycling. The objective was to elucidate the role of extrusion temperature and screw speed in modulating the quality of recycled PLA filament, as well as in controlling its dimensional attributes. Recycled PLA pellets (3D850D) were extruded using a single filament extruder machine within an extrusion temperature range of 145°C to 165°C and a screw speed varying from 2 rpm to 6 rpm. The extruded filaments were subsequently 3D printed into specimens adopting a 0° raster angle, line infill pattern, and a 100 percent infill density, then tested as per ASTM D638 mechanical standards. The study revealed a profound influence of extrusion parameters on the filament's ultimate tensile strength, yield strength, and diameter. Optimal extrusion conditions - 155°C and 5 rpm - resulted in maximum mechanical strengths, while the parameters yielding filament diameters closest to commercial standards were identified as 5 rpm and 155°C. These results under-score the possibility of optimizing the recycled PLA filament's properties through adept control of extrusion parameters. Consequently, this investigation supports the potential use of recycled PLA filament in the 3D printing industry as a sustainable and performance-efficient material, offering a tangible step towards environmentally friendly additive manufacturing practices.

Extrusion and characterization of recycled polyethylene terephthalate (rPET) filaments compounded with chain extender and impact modifiers for material-extrusion additive manufacturing

The continuous growth of annual production and consumption of polyethylene terephthalate (PET) is coined with increasing waste that leaks into the environment, landfills and oceans as microplastics and nano plastics fragments. Upcycling the recycled PET to make a feedstock for the fast-growing material-extrusion additive manufacturing (MEX-AM) technology can contribute to the solution and supports the concept of sustainable materials. In this work, extrudable filaments comprising recycled polyethylene terephthalate (rPET) with low-cost additives, such as pyromellitic dianhydride (PMDA) as a chain extender, styrene-ethylene-butylene-styrene terpolymer functionalized with maleic anhydride (SEBS-g-MA), a thermal modifier and toughening agent, ethylene-ethyl acrylate-glycidyl methacrylate terpolymer (E-EA-GMA), a functional reactive elastomeric impact modifier and ethylene-ethyl-acrylate (EEA), a non-reactive elastomeric impact modifier, have been fabricated using the twin-screw extruder. The optimum extrusion process parameters for producing uniform filaments of different rPET compounded formulations have been identified, this includes the extrusion die temperature of 280 °C and the screw speed of 150 ± 3 rpm. The compounded filaments are then printed into standard ASTM test specimens for thermal characterization and mechanical characterization, including glass transition and melting temperatures, crystallinity and crystallization temperature, tensile strength, tensile modulus, ductility, flexural strength, and Izod impact energy. Furthermore, the melt flow index for the filaments was measured. More significantly, the experimental data showed that compounding rPET with such additives in the reactive twin-screw extrusion process results in uniform filaments that display advantageous thermal and mechanical properties and can be used as a feedstock in the MEX-AM technology. This study suggests that compounding the recycled PET pellets with low-cost additives while extruding them into filaments for MEX-AM offers excellent potential to make high-value-added customized products from a sustainable polymer feedstock, such as prototyping, tooling, testing components or end-use internal components for small machines and cars.

Optimization of numerical parameters and microstructure evolution on 2195 Al–Li alloy extrusion process

The present study designed a set of extrusion dies with unequal bearing lengths to investigate the extrusion deformation behavior of 2195 Al–Li alloy. With the standard deviation of the velocity field (SDV) and extrusion force as optimization objectives, the extrusion process parameters (billet temperature, die temperature and extrusion speed) were optimized using Taguchi method and orthogonal test. The results indicate that billet temperature is the most significant factor affecting SDV and extrusion force, with a range of 1.287 and 7.076, respectively. Furthermore, the optimal extrusion parameters were determined as billet temperature 420 °C, die temperature 410 °C and extrusion speed 0.2 mm/s, resulting in the SDV value of 0.3345 and the extrusion force of 17.059 MN. The grains on the extruded profile were flattened and elongated both in the extrusion direction and cross-section, showing obvious <111>∥TD and <100>∥TD preferred orientation, and discontinuous dynamic recrystallization (DDRX) and geometric dynamic recrystallization (GDRX) mostly occurred, but no significant differences in grain size were observed, thus verifying the accuracy of the numerical simulation. Additionally, the ultimate tensile strength, yield strength and elongation of the extruded profile reached 437.1 MPa, 345.9 MPa and 11.7%, respectively.