Extrusion Process Parameters Research Articles

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.

High methoxyl pectin can improve the extrusion characteristics and increase the dietary fiber content of starch-cellulose extrudates.

Improving total dietary fiber content while maintaining the texture/expansion of extruded products is a challenge. Pectin has a dual function; it is a source of dietary fiber and it also functions as a hydrocolloid, which could improve the texture of high-fiber extruded foods. The objective of this study was to evaluate the impacts of pectin types from citrus peel on the expansion characteristics of starch-cellulose extrudates. High and low methoxyl pectin (HMP and LMP) was added to the starch-cellulose mixtures and extruded using a twin-screw extruder. The pasting properties of raw mixtures, extrusion properties, microstructure, and dietary fiber contents of the extrudates were studied. The inclusion of HMP in raw materialimproved the peak viscosity (629.7±8.1 to 754.7±80.1 mPa s) and maintained the final viscosity compared to the control (starch-cellulose mixture alone), unlike LMP. HMP relatively maintained the extrusion process parameters such as torque, back pressure, and specific mechanical energy as the control. Interestingly, the addition of 7% of HMP had a similar expansion ratio (3.41±0.08 to 2.35±0.06) compared to the control (3.46±0.08 to 2.32±0.09) under the extrusion conditions studied. The total dietary fiber content improved from 12.22±0.01% to 18.26±0.63% (w/w). HMP maintained the expansion characteristic of starch-cellulose extrudates and improved its total dietary fiber content relative to LMP. Adding HMP to the mixtures improved the extensibility of the melt, favoring bubble growth and expansion of the starch-cellulose extrudates. Fourier transform infrared spectroscopy data suggested that there could be intermolecular interactions between starch, cellulose, and pectin, but the nature of these interactions needs further investigation. PRACTICAL APPLICATION: The study provides practical information on the influence of the addition of high and low methoxyl pectin on starch-cellulose extrudates. The results can help the industry to produce snack products that are more nutritious but are still well accepted by the consumers.

Optimization of Hot Backward Extrusion Process Parameters for Seamless Tube of Mg-8Gd-3Y Alloy by Finite Element Simulation

Optimization of Hot Backward Extrusion Process Parameters for Seamless Tube of Mg-8Gd-3Y Alloy by Finite Element Simulation

Multilayer 3D bioprinting and complex mechanical properties of alginate-gelatin mesostructures

In the biomedical field, extrusion-based 3D bioprinting has emerged as a promising technique to fabricate tissue replacements. However, a main challenge is to find suitable bioinks and reproducible procedures that ensure good printability and generate final printed constructs with high shape fidelity, similarity to the designed model, and controllable mechanical properties. In this study, our main goal is to 3D print multilayered structures from alginate-gelatin (AG) hydrogels and to quantify their complex mechanical properties with particular focus on the effects of the extrusion process and geometrical parameters, i.e. different mesostructures and macroporosities. We first introduce a procedure including a pre-cooling step and optimized printing parameters to control and improve the printability of AG hydrogels based on rheological tests and printability studies. Through this procedure, we significantly improve the printability and flow stability of AG hydrogels and successfully fabricate well-defined constructs similar to our design models. Our subsequent complex mechanical analyses highlight that the extrusion process and the mesostructure, characterized by pore size, layer height and filament diameter, significantly change the complex mechanical response of printed constructs. The presented approach and the corresponding results have important implications for future 3D bioprinting applications when aiming to produce replacements with good structural integrity and defined mechanical properties similar to the native tissue, especially in soft tissue engineering. The approach is also applicable to the printing of gelatin-based hydrogels with different accompanying materials, concentrations, or cells.

Optimization of hot extrusion process parameters for 7075 aluminum alloy rims based on HyperXtrude

Aluminum alloy has the characteristics of light weight, high strength, corrosion resistance, easy forming, etc., and is widely used in manufacturing industry. The extrusion speed of aluminum alloy rim is not uniform, which affects the mechanical properties of the product. In order to solve these 1problems, the finite element analysis model of hot extrusion of aluminum alloy profiles was established in HyperXtrude software. The influences of different bar diameters, hot extrusion velocity, bar preheating temperature, die temperature and extrusion cylinder temperature on velocity difference and maximum extrusion pressure at the exit were analyzed. The results show that the designed hot extrusion rim die meets the requirements of strength and deformation, and the best extrusion process parameters of 7075 aluminum alloy rim profiles in improving profile quality and reducing energy consumption are obtained by Taguchi test gray correlation method.

Developing Filament Extruder and Characterization of Recycled High-Density Polyethylene for 3D Printing Filament Material

With the rise of additive manufacturing, the demand for 3D printing feedstock has increased exponentially and its sustainability is critical in the future. Many scholars are now concerned about how 3D printing filaments should be reproduced from recycled plastic. This study aimed to develop a filament extruder machine and investigate the potential of using recycled high-density polyethylene (HDPE), one of the most commonly used and recyclable thermoplastic, for 3D printing filament material. Desktop sized filament extruder machine was built, and a smooth and round-shaped 1.75±0.01mm diameter recycled HDPE filament was produced. Its mechanical, thermal, chemical, and physical properties were characterized by conducting various tests and validation test was conducted by comparing its properties with its virgin counterpart. The ultimate tensile strength of the recycled HDPE filament was obtained 19.02±0.35MPa, which is comparable to the ultimate tensile strength of virgin HDPE, making it a viable 3D printing feedstock for rapid prototyping. According to Thermogravimetric analysis (TGA), the recycled HDPE filament offers significant thermal stability with an onset degradation temperature of 430℃ and a full degradation temperature of 520℃. Its Fourier Transform Infrared (FTIR) spectrum shows the same functional groups as virgin HDPE polymer. The recycled HDPE filament has also excellent water-rejecting capability. In general, the study revealed a promising result for the use of recycled HDPE plastic as a more sustainable and environmentally friendly source material for 3D printing filament. To increase the potential and market competitiveness of recycled filaments, further investigation is required to optimize the filament extrusion and 3D printing process parameters, improve the mechanical properties, and overall development methods for both the recycled HDPE filament and 3D printed products.

Effect of extrusion processing parameters on structure, texture and dietary fibre composition of directly expanded wholegrain oat-based matrices

Oat flour mixed with 30 g/100 g rice flour was extruded with a twin-screw extruder using a central composite orthogonal design. Temperatures (120 °C,140 °C, 160 °C) and moisture (14.5 g/100 g, 17.7 g/100 g, 20.6 g/100 g) were adjusted during extrusion, while screw speed was kept constant (400 rpm). Extrudates were analysed for structure (expansion, density, microstructure), texture (hardness), β-glucan (molecular weight and extractability), as well as fibre content. Expansion varied between 250 and 329%, density between 165 and 457 kg/m3 and hardness between 27 and 64 N. The response surface model showed that more expanded, less dense and less hard extrudates were achieved at low moisture, while high temperature resulted in lower density and hardness. Significant differences in β-glucan extractability were observed depending on extrusion conditions, with values ranging between 0.64 and 1.31 g/100 g. β-glucan extractability correlated with positively with porosity, and negatively with moisture content during extrusion, cell wall thickness and density. The results indicate that conditions that produce a more porous, crispier structure, also increases β-glucan extractability.

Experimental study on mechanical properties of material extrusion additive manufactured parts from recycled glass fibre-reinforced polypropylene composite

This paper presents an optimised material extrusion (MEX) 3D printing method with feedstock produced from glass fibre reinforced polypropylene (GFRPP) composite waste and investigates the effect of glass fibre weight fraction (0%, 15%, 30%, 40%) on the printability and mechanical properties of filaments and printed specimens. GFRPP feedstock filaments were fabricated by optimising the filament extrusion process parameters. The highest ultimate tensile strength (112 MPa) was obtained in a filament with 40% fibre weight content. In addition, repeated recycling of filament was shown to reduce the fibre aspect ratio and enhance the filament quality. It was shown that the increase in glass fibre content from 0% to 40% improved the ultimate tensile strength of MEX 3D printed specimens from 14.7 MPa to 23.4 MPa as well as the flexural strength of MEX 3D printed samples from 11.68 MPa to 66.55 MPa. The increase in fibre weight content from 30% to 40% had a minimal effect (+1%) on the ultimate tensile strength of the printed samples. In addition, the 40% filaments exhibited a more brittle behaviour, rendering them less suitable for MEX 3D printing than 30% GFRPP. The results showed that waste industrial GFRPP material can be effectively enhanced and converted to short fibre reinforced material extrusion filament feedstock for the printing of components as a circular economy demonstrator.

Estimation of Extrusion Process Parameters in Tire Manufacturing Industry using Random Forest Classifier

The extrusion process is a very complex process due to the number of process parameters involved. Throughout the workflow process, the process parameters are determined by trial-and-error method according to the recipe of materials. This technique causes loss of production and time as well as energy consumption. In extrusion, temperature and speed parameters are very important to obtain a homogeneous raw material product input and high-quality extruded products. It is necessary to monitor the temperature changes and process speed control during the flow of the molten raw material between the barrels of the extruder machine, which is the extrusion equipment. By monitoring the extruder in real time, estimating the extrusion process parameters according to the amount of product to be produced will make the extrusion process operations more efficient. In this study, a classification algorithm to process these parameters is developed in the “Pycharm” environment and the model is trained with the supervised learning method using the image processing algorithm outputs. The model is able to estimate the extruder 'speed and temperature parameters' and the 'ready to run' decision of the machine with 93% success for different production quantities entered by the operator.

Optimisation of extrusion process parameters to make ABS-PC filament for 3D printing using Taguchi-GRA technique

ABSTRACT This paper attempts to optimise the single screw extrusion (SSE) process parameters for extruding Acrylonitrile-butadiene-styrene (ABS) and Polycarbonate (PC) blend filament, having improved tensile strength and melt flow rate. The melt flow and mechanical properties of ABS-PC blend filament are highly reliant on the SSE process parameters. Thus, optimising the process parameters to fabricate the blend filaments with high performance has become essential. Grey relational analysis has been integrated with the Taguchi method to optimise the SSE process parameters by evaluating the grey relational grades in terms of the performance index. Experimentation has been carried out according to Taguchi’s L9 orthogonal array (OA), which has been designed considering three SSE process parameters, i.e. screw rotation, blend composition and chamber temperature. The co-continuous structure and compatibility between the phases of the blend obtained at ABS:PC 50:50 by wt%. Micrographs and thermographs support the results. The tensile strength of the 3D printed ABS:PC 50:50 by wt.% composite specimen has improved by 38.02% as compared to virgin ABS.

An interpretable boosting-based predictive model for transformation temperatures of shape memory alloys

In this study, we demonstrate how the incorporation of appropriate feature engineering together with the selection of a Machine Learning (ML) algorithm that best suits the available dataset, leads to the development of a predictive model for transformation temperatures that can be applied to a wide range of shape memory alloys. We develop a gradient boosting ML surrogate model capable of predicting Martensite Start, Martensite Finish, Austenite Start, and Austenite Finish transformation temperatures with an average accuracy of more than 95% by explicitly taking care of potential distribution changes when modeling different alloy systems. We included heat treatment, rolling, extrusion processing parameters, and alloy system categorical features in the model input features to achieve more accurate and realistic results. In addition, using Shapley values, which are calculated based on the average marginal contribution of features to all possible coalitions, this study was able to gain insights into the governing features and their effect on predicted transformation temperatures, providing a unique opportunity to examine the critical parameters and features in martensite transformation temperatures.

Extrusion as a tool to enhance the nutritional and bioactive potential of cereal and legume by-products

Cereal and legume by-products obtained from primary food production industries pose an environmental and economic problem. Nevertheless, these residues can potentially yield value-added products due to their elevated content of dietary fiber, phytochemicals, vitamins, minerals, and residual levels of proteins, which makes them a suitable and heightened option for reutilization in human consumption. Several studies identify extrusion as an innovative technology to modify the technofunctionality and nutritional properties of cereal and legume by-products, resulting in the production of improved ingredients. This review focuses on studies that evaluate the effect of extrusion to improve the nutritional and bioactive potential of cereal and legume by-products. A revision of the extrusion process parameters that improve the profile and bioavailability of dietary fiber, proteins, and phenolic compounds, and minimize antinutritional factors associated to cereal and legume by-products was done. The composition of by-products and process parameters such as feed moisture, barrel temperature and screw speed influence the resulting effect of extrusion. Studies suggest that extruding composite feedstock containing cereal or legume by-products may limit the molecular modifications that trigger the nutritional improvements. Therefore, extrusion applied as a pretreatment represents an interesting and economic alternative to improve the profile and bioavailability of the nutrients found in cereal and legume by-products which might lead to the development of functional ingredients useful to produce foods aimed to prevent chronic diseases.

Prediction of Recrystallization Structure of 2A12 Aluminum Alloy Pipe Extrusion Process Based on BP Neural Network

2A12 aluminum alloy is a high-strength aerospace alloy. During its extrusion process, the extrusion process parameters have a great impact on the microstructure evolution of the extruded products. There are three extrusion process parameters controlled in the actual project, which are the initial temperature of billet, the initial temperature of die and the extrusion speed. Combined with a back propagation (BP) neural network and finite element method (FEM) simulation, based on the constitutive equation and recrystallization evolution process of 2A12 aluminum alloy, this paper establishes a prediction model for the grain size of extruded pipe by these three extrusion process parameters. This paper used a 35MN extruding machine for a production verification of 2A12 pipe. The results show that the predicted grain size is 3% smaller than the actual size.

Optimization for the Contrary-Rotating Double-Screw Extrusion of Plastics

A novel computer optimization system for the contrary-rotating double-screw extrusion of plastics was developed in this study. The optimization was based on the process simulation performed with the use of the global contrary-rotating double-screw extrusion software TSEM. The process was optimized using the GASEOTWIN software developed for this purpose using genetic algorithms. Several examples of optimization of the contrary-rotating double screw extrusion process parameters, i.e., the extrusion throughput, and minimize the plastic melt temperature and the plastic melting length.

Research of stamping of unequal channels. Part 7. Kinematic and stress states of the workpiece under constrained extrusion. 2. Plastic area under the punch end near the formed thick wall

The problem of determining the kinematic and stressed states of the workpiece under partially constrained extrusion of channels under plane strain conditions with a misaligned location of the punch and matrix is considered. The flow velocities and stresses in the plastic deformation zone under the punch end near the formed thick wall of the channel are determined. Formulas for the extrusion process parameters of unequal-shelf channels with a thin horizontal bridge are obtained. Keywords: die forging, extrusion, misalignment of punch and matrix, plane strain, plastic flow rate, stresses.mt13@bmstu.ru

Development, Characterization and Sensory Evaluation of an Extruded Snack Using Fig Molasses By-Product and Corn Semolina.

The effects of extrusion process parameters on the physicochemical, pasting and technological properties of ready-to-eat snacks were evaluated. The aim was to develop fortified extruded products with fig molasses by-product powder (FMP), which is created as a result of the production of fig molasses, is not currently used in food industry, and may cause environmental problems. The feed humidity was changed to 14-17-20%, the die temperature was 140-160-180 °C and the ratio of FMP was 0-7-14% at a fixed screw speed of 325 rpm. The study showed that adding FMP to extruded products had a significant effect on colour properties, water solubility and water absorption index properties. İncreasing the FMP ratio had a significant reducing effect on dough properties of non-extruded mixtures such as peak viscosity (PV), final viscosity (FV) and setback viscosity (SB). The optimum conditions for the production of snacks were found to be 7% FMP, 155.44 °C die temperature and 14.69% humidity. It was determined that the estimated values of water absorption index (WAI) and water solubility index (WSI) for the products manufactured under ideal extrusion conditions were close to the obtained values, and that there was no significant difference between the estimated values of the other response variables and their actual values.

A study of interfaces in 7075/Zr44Ti11Cu10Ni10Be25(Vit1b)/AZ31B composites

In order to achieve reliable connection between magnesium and aluminum alloys and to prepare composite structures and devices with excellent overall performance, it is critical to avoid the formation of brittle intermetallic compounds. In this regard, we describe hot stacked extrusion forming of 7075/Zr44Ti11Cu10Ni10Be25(Vit1b)/AZ31B in terms of extrusion process parameters and their influence on structure, interfaces, and mechanical properties. The study demonstrated that the composite had almost no defects such as extruded flying edges or bending. The nature of the samples varied considerably and the 450°C-4 mm/min sample showed a more desirable bonding appearance. The samples obtained under different extrusion conditions experienced different degrees of elemental diffusion at the interfaces. It is underscored that using amorphous alloy as the joining medium can effectively improve the strength of 7075/Vit1b/AZ31B composites, with the tensile strength increased by 12.5%. The 7075/Vit1b and AZ31B/Vit1b interfaces were studied systematically and the Al concentration layer was found at the AZ31B/Vit1b interface.

3D printing of microalgae-enriched cookie dough: determining feasible regions of process parameters for continuous extrusion

Microalgae can be part of the solution to the global food crisis, as they have high nutritional values. Recently, 3D printing of microalgae-enriched snacks has been reported with the capability to customize nutritional profiles, shapes, and textures of the snacks. Because the process parameters of extrusion-based 3D printing affect the printability of cookie dough, it is important to know the levels of process parameters leading to continuous extrusion. This study investigated feasible regions of printing process parameters for continuous extrusion of microalgae (Arthrospira Platensis) enriched cookie dough. The process parameters studied were nozzle diameter, printing speed, and air pressure. The feasible regions were determined by visual inspections of printed strands. The results show that, for smaller nozzle diameters and higher printing speeds, higher air pressures are required to ensure continuous extrusion. The identified feasible regions from this study would be helpful when deciding the appropriate nozzle diameter, printing speed, and air pressure to print microalgae-enriched cookie dough and other materials with similar rheological properties in extrusion-based 3D printing.

EFFECT OF EXTRUSION PARAMETERS ON PHYSICAL PROPERTIES OF TUR DAL (PIGEON PEA) ANALOGUES DEVELOPED FROM TUR DAL BROKENS

Dehusking and splitting are typically the steps involved in converting pulses into dal. The milling losses in commercial pulse mills can be attributed to the small brokens and fine powders found during scoring and concurrent dehusking and splitting operations. The fracture of dal kernels during the milling process is a problem in the dal milling industry, and customers don’t generally like these broken kernels. The only way to turn these unused milling fractions into profitable products is through extrusion cooking. Extrusion cooking of flour of redgram dal brokens with addition of some additives was done to prepare Tur dal analogues at various extrusion process parameters. The effect of barrel temperature (120 – 175 oC), feed moisture content (18-25%), feed rate (40-60 kg/h) and screw speed (100-220 rpm) on bulk density, expansion ratio and hardness of Tur dal analogues were investigated. To develop the prediction model, a central composite rotable design (CCRD) using response surface method (RSM) was applied. Each variable’s impact on the responses was measured via regression equations. The second-order quadratic regression model fit the variation adequately. The significance was established at p0.05. An increase in bulk density and decrease in expansion ratio with increase in feed moisture content and feed rate was observed. The bulk density and hardness increased as the barrel temperature increased when the feed moisture content was lower; conversely, when the feed moisture content was higher, the bulk density and hardness reduced as the barrel temperature increases.