Simulation Of Extrusion Research Articles

Application of a shear cell for the simulation of extrusion to test the structurability of raw materials

The required raw material properties and the mechanisms behind fibrous structure formation during high moisture extrusion cooking (HMEC) to produce plant-based meat analogues are not sufficiently understood. The implementation of new raw materials is therefore a labour-intensive, empirical endeavour. Hence, this research explores the potential of a high-pressure shear cell (HPSC) as a tool for rapid screening of raw materials for HMEC suitability. During these texturisation tests, material viscosity was monitored to gain deeper mechanistic insights. For that, hydrated pea protein isolate (PPI) and soy protein concentrate (SPC) were sheared at 5-40 s−1 in the HPSC with a cone-plate or plate-plate geometry under extrusion-like conditions at 140–160 °C and 20 bar. Fibrous structures were successfully generated with both tested plant proteins, but reproducibility was limited to trials with SPC. Monitoring of viscoelastic properties revealed an onsetting polymerisation, followed by a decrease in viscosity, indicating fracturing of the forming network as underlying structuring mechanism. The suggested fracturing of an emerging network aligns with an observed increase in fibrousness in the plate-plate geometry compared to the cone-plate geometry due to the radial shear rate gradient. Finally, this research showcased a high similarity of the process-structure response pattern for SPC between the applied HPSC process and HMEC. Yet, further modifications, such as increasing the mechanical energy input capacity, are required to effectively apply HPSC processing for the prediction of the structuring behaviour in HMEC for the broad range of existing raw materials.

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.

Compatibility study of recycled Polypropylene (PP)/Poly(ethylene terephthalate) (PET) blends nanocomposites with PP‐g‐MAH: Modeling of twin screw extrusion

AbstractAlthough the utilization of recycled polymers is essential to sustain the environment, conventional recycled polymers face limitations in application due to the degradation of their properties caused by impurities. To solve the problem the performance deterioration of these recycled polymers, this study aimed to enhance their compatibility by chemically adding polypropylene‐graft‐maleic anhydride (PP‐g‐MAH) and physically manipulate a screw profile by using an extrusion simulation program. As a result of applying the optimized extrusion process set by the simulation program, significant improvements in the compatibility and dispersion of fillers within the polymer were observed through scanning electron microscopy image analysis. In addition, through detailed analysis of rheological data, the positive impact of adding compatibilizer and changing screw profile on rheological properties was demonstrated. As the compatibility of recycled polymer blends improved, tensile strength increased by approximately two‐fold and thermal conductivity was significantly improved, which were decisive factors in dramatically enhancing the performance of recycled polymers. These improved polymer properties provide an opportunity for recycled polymers to be applied more broadly and will expand the potential for new applications in various industrial fields.

Numerical modeling of fiber orientation in multi-layer, isothermal material-extrusion big area additive manufacturing

Fiber orientation is a critical factor in determining the mechanical, electrical, and thermal properties of 3D-printed short-fiber polymer composites. However, the current numerical studies on predicting fiber orientation are limited to straight single-strand configurations, while the actual printed parts are often composed of complex multi-layer structures. To address this issue, we conducted numerical simulations of material extrusion in multi-layer big-area additive manufacturing without any post-deposition strand morphology modification mechanism. By examining the effects of material properties and printing conditions when extruding and depositing strands on a fixed substrate as well as previously deposited layers, it was possible to observe the complex interplay between multiple layers and its impact on fiber orientation. The work and methodology presented in this paper can be used to identify optimal extrusion-to-nozzle speed ratios, material rheology, fiber content, and fiber aspect ratio to achieve the desired performance and thermo/mechanical properties of additively manufactured parts. This work is an important contribution towards the manufacture of high-performance, short-fiber polymer composites as the presented methodology can enable engineers to precisely predict and tailor the fiber orientation in 3D printed parts.

In situ conductometry for studying the homogenization of Al-Mg-Si alloys and predicting extrudate grain structure through machine learning

In industrial practice, no sensors capable of obtaining microstructural information in situ during thermo-mechanical processing of Al alloys are commonly employed. Inductive electrical conductivity measurement is safe, inexpensive, and capable of acquiring valuable information about precipitation and dissolution processes. However, commercial eddy current sensors work only at low temperatures near room temperature and are thus not suitable for in situ conductometry during heat treatments of Al alloys. We designed a high-temperature eddy current sensor and performed in situ conductometry during the homogenization of six Al-Mg-Si wrought alloys, three of which are experimental recycling-friendly alloys with increased Fe content. The results are interpreted with regard to microstructural investigations, and the advantages and limitations of our approach are discussed. As a proof-of-concept, we show how the conductivity curves and extrusion process parameters can be combined to predict final extrudate grain structures using machine learning. To achieve this, we employed finite element simulation of extrusion coupled with microstructural simulation over a wide parameter range, validated by extrusion experiments and metallography, and trained a feedforward neural network. We believe our interdisciplinary approach can lead to improvements in the industrial processing of Al wrought alloys.

Numerical simulation of friction extrusion: process characteristics and material deformation due to friction

This study employs a finite element thermo-mechanical model, using a Lagrangian incremental setting to investigate friction extrusion (FE) under varying process conditions. The incorporation of rotation in FE generates substantial frictional heat, leading to significantly reduced process forces in comparison to conventional extrusion (CE). The model reveals the interplay between temperature, strain, and strain rate across different microstructural zones of the resulting wire. Specifically, the sticking friction condition in FE enhances initial shear deformation, aligning with a homogeneous spatial strain distribution and predicting complete grain refinement in the extruded wire, as per Zener-Hollomon calculations. On the other hand, under the sliding friction condition in FE, the shear deformation is reduced which results in an inhomogeneous microstructure in the extruded wire. The analysis of material flow in the workpiece reveals distinct transitions from the base material to the thermo-mechanically affected zones. The simulated process force, thermal history, and microstructure during sliding friction conditions align well with the findings from performed friction extrusion experiments.

MATHEMATICAL MODELING OF COMPLEX-SHAPED WORKPIECE FORMING FROM ULTRAFINE-GRAINED TI ALLOY AND SUBSEQUENT DEPOSITION OF PROTECTIVE COATINGS BASED ON HIGH-ENTROPY ALLOY

The paper reports on finite element simulation of extrusion of a complex-shaped workpiece made of the ultrafine-grained Ti-6Al-4V alloy and vacuum-arc deposition of a protective coating based on the TiVZrCrAl high-entropy alloy. Temperature fields formed in the workpiece during extrusion are studied. Strain-induced heating and the necessary forming force are determined for the initial temperature-rate conditions. The distribution of strain intensity in the workpiece during extrusion is also analyzed. According to the obtained data, the chosen temperature-rate conditions allow using the ultrafine-grained titanium alloy as the initial workpiece without deteriorating its mechanical characteristics. Computer simulation of the coating deposition on the complex-shaped workpiece provides values of the temperature, chemical composition, and thickness of the high-entropy coating. Thus, the coating thickness is about 6.5-7.5 μm, and the surface heating temperature during the deposition process is within 368-597°C, which allows retaining the ultrafine-grained structure in the alloy.

Optimization analysis of cold extrusion process parameters for valve screws

This study focuses on valve screws and establishes a cold extrusion simulation model using DEFORM-3D software to analyze the deformation characteristics and influencing factors during the extrusion process. Supported by the theory of rigid-plastic finite element, an orthogonal experimental design is conducted to establish a four-factor three-level simulation scheme with general fillet radius, die clearance, extrusion speed, and friction coefficient as the simulation variables, and maximum equivalent stress on the convex die, forming damage of the blank, and maximum wear depth on the concave die as the objective values. The prediction model based on BP neural network algorithm and orthogonal experimental data shows high accuracy. The optimization problem is simplified into a dimensionless numerical analysis problem using GC grey correlation analysis, and the optimal solutions within each variable range are determined using range analysis. The simulation results after optimization show a 20 5% reduction in maximum equivalent stress on the convex die compared to the original scheme, a 4.9% reduction in forming damage of the extruded part, and a 24.24% reduction in maximum wear depth on the concave die compared to before optimization. The actual verification confirms the good forming effect of valve screw extrusion, with well-formed contours and a uniform surface without wrinkles or defects. Finite element simulation provides valuable guidance for practical production.

The ECM and tissue architecture are major determinants of early invasion mediated by E-cadherin dysfunction

Germline mutations of E-cadherin cause Hereditary Diffuse Gastric Cancer (HDGC), a highly invasive cancer syndrome characterised by the occurrence of diffuse-type gastric carcinoma and lobular breast cancer. In this disease, E-cadherin-defective cells are detected invading the adjacent stroma since very early stages. Although E-cadherin loss is well established as a triggering event, other determinants of the invasive process persist largely unknown. Herein, we develop an experimental strategy that comprises in vitro extrusion assays using E-cadherin mutants associated to HDGC, as well as mathematical models epitomising epithelial dynamics and its interaction with the extracellular matrix (ECM). In vitro, we verify that E-cadherin dysfunctional cells detach from the epithelial monolayer and extrude basally into the ECM. Through phase-field modelling we demonstrate that, aside from loss of cell-cell adhesion, increased ECM attachment further raises basal extrusion efficiency. Importantly, by combining phase-field and vertex model simulations, we show that the cylindrical structure of gastric glands strongly promotes the cell’s invasive ability. Moreover, we validate our findings using a dissipative particle dynamics simulation of epithelial extrusion. Overall, we provide the first evidence that cancer cell invasion is the outcome of defective cell-cell linkages, abnormal interplay with the ECM, and a favourable 3D tissue structure.

Investigation of parameters affecting longitudinal seam quality of aluminum extruded profiles

The main reason for the preference of aluminum material is its low density. Aluminum material density is 1/3 of steel. When we compare aluminum material in terms of specific strength (strength/density), it gives even better value than very high strength steels. Aluminum extrusion is a crucial method for producing structural profiles with superior properties, especially for the rail and automotive industries, driving the need for optimal processing conditions.It is known that the most common problem in structural alloys is longitudinal welding seam quality. In porthole-bridge dies, the material inlet occurs from the die ports and every bridge being between each port keeps the inner chambers of the profile in position. The billet inflated inside barrel until barrel diameter is injected to dies’ ports by dividing by the number of ports of die under pressure of press and it recombines under the influence of pressure and temperature in the boiling chamber under the die legs and takes its final shape by passing through the die transitions (bearing). The quality of this joint varies by depending on the material property, the boiling pressure in the boiling chamber, the temperature of the material, the size and geometry of the boiling chamber and transition channel, the surface cleanliness of the material and the state of the oxide layer, etc.In this study, the effects of die legs’ form, extrusion speed and billet temperature were investigated with QForm aluminum extrusion simulation program. In order to determine the accuracy of the examinations, the die used in the simulation was manufactured and test productions were made in the 55 MN aluminum extrusion press with the simulation parameters. Mechanical and metallographic tests were performed with the samples taken from the production, and the results were compared with the simulation results. As a result, the effect of legs form and extrusion parameters on the quality of weld seam was determined.

Modelling of roller conveyor for the simulation of rubber tire tread extrusion

Abstract The extrusion of large or heavy technical rubber profiles is usually assisted by a conveying device. Such a device can be a conveyor belt or a series of rollers, and its use is necessary mainly for being able to achieve the process. Within the context of numerical simulation of extrusion flows, a conveying device brings additional downstream constraints to the flow governing equations. In the present paper, we propose a simple engineering approach for modelling a roller conveyor used in rubber tire tread extrusion, and we apply it to the extrusion simulation of a flat tire tread profile as typically encountered in the tire manufacturing industry.

Flow simulation and experimental validation of polymer extrusion using additively manufactured carbon fiber reinforced PEEK dies

Recent developments in polymer additive manufacturing (AM) have enabled composite materials and tough polymers such as Carbon-Fiber (CF)-reinforced Polyether-Ether-Ketone (PEEK), to be processed by Fused Filament Fabrication (FFF). CF-PEEK is a particularly strong and highly thermal resistant material that can overcome the limitations of polymer AM dies used in polymer profile extrusion with high demanding process conditions. Furthermore, AM offers flexibility by enabling streamlined die design which results in more flow balance and lower die head pressure compared to the flat die design. Flow simulations were performed in this study to predict the die head pressure and melt flow velocity across the profile extrusion section. The die design profile used for simulation has a cross section composed of two circular features connected by a horizontal line and non-uniform wall thickness. The flow simulation was validated by experimental testing of CF-PEEK AM dies in a single screw extruder operated at five different screw speed settings. The input for the simulations was the mass flowrate which was calculated from actual experiments depending on the mass of polymer extrudates and the corresponding extrusion time for each screw speed. The flow simulation includes a non-isothermal model that couples the polymer melt flow and the heat transfer across the melt. The viscosity model coefficients of the extruded materials (polypropylene, PP, and acrylonitrile butadiene styrene, ABS) used in the simulation were obtained from actual rheology testing. The simulation results indicate that the deviation of die head pressure from experimental testing is within 1-13% for PP and within 22-29% for ABS.

Numerical simulation of extrusion of FeMnSiCrNi/NiTiNb dissimilar shape memory alloy composite tube based on finite element method and cellular automaton

FeMnSiCrNi/NiTiNb dissimilar shape memory alloy composite tube is firstly put forward and it can be fabricated by means of isothermal extrusion. Based on Arrhenius constitutive model of FeMnSiCrNi and NiTiNb shape memory alloys, isothermal extrusion of FeMnSiCrNi/NiTiNb dissimilar shape memory alloy composite tube is simulated by rigid viscoplastic finite element method. It can be found that the deformation zone of the dissimilar shape memory alloy composite tube is always in a three-dimensional compressive stress state during extrusion, and the deformation of the inner tube is obviously higher than that of the outer tube. It is necessary to guarantee the interface compatibility between the inner tube and the outer tube during isothermal extrusion of FeMnSiCrNi/NiTiNb dissimilar shape memory alloy composite tube. The relationship between macroscopic process variables and microscopic variables during plastic deformation of FeMnSiCrNi shape memory alloy tube at high temperature is established by coupling finite element simulation and cellular automaton simulation. The microstructural evolution of FeMnSiCrNi shape memory alloy in different deformation zones during isothermal extrusion of dissimilar shape memory alloy composite tube is simulated. It can be concluded that the grain size of dynamic recrystallization is reduced with the increase of plastic strain in the deformation zone.

Neural networks and NARXs to replicate extrusion simulation in digital twins for fused filament fabrication

In this work we propose the use of nonlinear autoregressive models with exogenous variables (NARXs), powered by dynamic recurrent neural networks, to replicate the results of a previously developed, complex simulation of the extrusion process in fused filament fabrication. The NARXs predict extrusion rate of the extrudate and compression force acting on the filament with an average discrepancy of 0.12 % with respect to the original simulation, but at a fraction of the computational time (0.1 s of the NARX vs. 600 s needed by the original simulation to process the same one-minute time interval). In addition to illustrating how NARXs can be created to mimic an existing simulation, in this work we show how the NARXs can be physically connected to the sensors of a real FFF machine, thus creating an effective digital twin of the extrusion process, useful to support real-time decision making by an AI machine controller. Finally, we show how the implemented digital twin can be used for in-process monitoring, bringing as example the automated detection of an extrusion clogging event.

Computational fluid dynamics modeling of multicomponent elastomeric complex profile while flowing through extrusion die

Extrusion is one of the most efficient and widely used methods for producing long elastomeric profiles, particularly for automotive industries. These include mono-component glass run, co-extrudate, multi-component, metal-reinforced rubber, and cellular elastomeric profiles. Die swell and the interface disturbance between the fluids creates additional complexities while designing an extrusion die for elastomeric products. The extrudate deformation depends on die geometry, processing parameters, and material properties of the elastomeric compound. In this study, the 3D model having three flow channels is constructed to perform the multi-component extrusion simulation with the help of computational fluid dynamics. Three different configurations of flowing material are considered; first for all the flow channels having the same material, second for two channels having the same material, and third for all the flow channels having different materials. The extrusion simulation was performed using shear rate dependent viscosity model and temperature-dependent viscosity model to compute the extrudate deformation along with the interfaces on carbon black filled ethylene propylene diene monomer rubber (EPDM) based elastomeric compound for a multi-component elastomeric profile. Moreover, the simulated results show that the extrudate having different materials possesses lower structural stability compared to the other two extrudates. Finally, the simulation carried out with a complex-shaped multi-component elastomeric profile revealed a good agreement with the structural profile of the physical extrudate.

Simulation of Coarse Grain Evolution during Hot Extrusion of Al-Mg-Si Alloy

Coarse grains at or near the surfaces of extruded aluminum profiles can have a major detri-mental influence on their ductility and surface quality. Thus, the extrusion industry aims to minimizecoarse grains while increasing the productivity of the process. Peripheral Coarse Grains (PCG) de-velop depending on local state variables such as temperature, strain and strain rate. Here we presenta microstructure based material model implemented into HyperXtrude™, capable of predicting thedevelopment of PCG by combining geometric Dynamic Recrystallization (gDRX) and conventionalgraingrowthmodels.Duetoitshistorydependence,themodelisimplementedtorunduringthewholetransient extrusion simulation. The first results of the predicted ram force as well as final grain distri-bution in the profile show reasonable agreement with experimental trials and electron backscattereddiffraction results.

Effect of Temperature on Surface Cracking Defects in AA7075 Hot Extrusion

Aluminum alloys in the 7000 series are high-strength alloys that are used in a wide variety of products in the transportation equipment and aerospace fields to reduce weight. In particular, the A7075 alloy has the highest strength and is expected to find further applications in a wide range of fields such as aircraft parts and sporting goods. However, low productivity is a problem due to its high deformation resistance, tendency to produce surface defects called tearing on the product surface, and short tool life. Tearing tends to occur under high temperature and high speed conditions, and is thought to be caused by local melting of Zn, an additive element, due to heat generation in processing. In this study, to improve the productivity of A7075 alloy, the profile was cooled during extrusion to prevent recrystallization of extrudate surface grains due to processing heat and to prevent processing heat during forming. In order to investigate the cooling effect, hot extrusion simulation was conducted. The cooling effect successfully suppressed the occurrence of tearing. These results indicate that cooling the extrudate during forming reduces the effect of heat generation during forming and prevents recrystallization of the extrudate surface grains and local melting of Zn.

Modeling Friction in HyperXtrude for Hot Forward Extrusion Simulation of EN AW 6060 and EN AW 6082 Alloys

In this work, different friction models available in HyperXtrude had been investigated in the context of hot forward extrusion simulation of aluminum alloys. Extrusion trials were carried out for EN AW 6060 and EN AW 6082 at different temperatures and ram speeds. The extrusion forces as well as material temperatures near the exit of the die were recorded and used for the validation of the simulations. FE-simulations of each extrusion trial were carried out in HyperXtrude. Initially, friction models were calibrated for only two extrusion trials. Then, these calibrated friction models were used to simulate the extrusion trials with different process parameters. Reasonably good agreements were observed between experiments and simulations in terms of extrusion forces. However, the simulations overpredicted the material temperature by almost up to 40 °C for extrusion trials with high ram speed.

Extrusion Simulation for the Design of Cereal and Legume Foods.

A 1D global twin-screw extrusion model, implemented in numerical software, Ludovic®, was applied to predict extrusion variables and, therefore, to design various starchy products with targeted structure and properties. An experimental database was built with seven starchy food formulations for manufacturing dense and expanded foods made from starches, starch blends, breakfast cereals, pulse crop ingredients such as pea flour, fava bean flour, and fava bean starch concentrated, and wheat flour enriched with wheat bran. This database includes the thermal and physical properties of the formulations at solid and molten states, melt viscosity model, extruder configurations and operating parameters, and extruded foods properties. Using extrusion and viscosity models, melt temperature (T) and specific mechanical energy (SME) were satisfactorily predicted. A sensitivity analysis of variables at die exit was performed on formulation, extruder configuration, and operating parameters, generating the extruder operating charts. Results allowed the establishment of relationships between predicted variables (T, SME, melt viscosity) and product features such as starch and protein structural change, density and cellular structure, and functional properties. The extrusion operating conditions leading to targeted food properties can be assessed from these relationships and also the relationship between extrusion operating parameters and variables provided by simulation.

Integrated numerical simulation and quality attributes of soybean protein isolate extrusion under different screw speeds and combinations

A numerical simulation of the fluid-dynamic parameters (shear rate distribution, shear viscosity distribution and residence time) inside the barrel combined with extrudate properties, is a potential novel approach for investigating molten soybean protein isolate (SPI) under different screw speeds and combinations. Through finite element simulation, computer fluid dynamics and particle tracking simulation analysis, it was found that increasing the screw speed can increase the shear rate, decreased the shear viscosity of the SPI fluid, and reduced the RDT, thereby promoting the dispersion degree. The maximum shear rate and minimum shear viscosity were generated at the screw flight flanks, and the fluid underwent an alternate shearing force in the barrel. A small axial channel width can significantly promote the fluidity of molten proteins. In conclusion, SPI extrudates with a homogenous structure, smooth surface, and favourable colour and textual profile were produced at a relatively high screw speed (140 rpm).