Extrusion System Research Articles

Influence of heated temperatures on PCM melting characteristics in a pneumatic-based extrusion system of fused deposition modeling: Experimental and numerical studies

Influence of heated temperatures on PCM melting characteristics in a pneumatic-based extrusion system of fused deposition modeling: Experimental and numerical studies

Potassium extrusion by plant cells: evolution from an emergency valve to a driver of long-distance transport.

The ability to accumulate nutrients is a hallmark for living creatures and plants evolved highly effective nutrient transport systems, especially for the uptake of potassium (K+). However, plants also developed mechanisms that enable the rapid extrusion of K+ in combination with anions. The combined release of K+ and anions is probably an ancient extrusion system, as it is found in the Characeae that are closely related to land plants. We postulate that the ion extrusion mechanisms have developed as an emergency valve, which enabled plant cells to rapidly reduce their turgor, and prevent them from bursting. Later in evolution, seed plants adapted this system for various responses, such as the closure of stomata, long-distance stress waves, dropping of leaves by pulvini, and loading of xylem vessels. We discuss the molecular nature of the transport proteins that are involved in ion extrusion-based functions of plants and describe the functions that they obtained during evolution.

Development of a novel concentrated solar-powered material extrusion system for producing printed circuit assemblies

A novel material extrusion system powered by Concentrated Solar Energy (CSE) for functional small-scale applications is proposed. The open literature has reported that any other system employs CSE to heat the extruding needle directly, which is the main component and function of any material extrusion device and the one that allows the building of the desired product or prototype. Polycaprolactone (PCL) is selected as the depositing material that gives shape to the substrates sheltering electric traces, resulting in a printed circuit assembly (PCA). A set of 15 experiments with different shapes allows the compilation of enough data to identify the exposure time and the direct radiation received as the main variables for obtaining the needed temperature for converting the depositing material to its rubbery state. Examples of functional circuits obtained by this device are included, showing his capabilities and potential. This information and the help of simulations on Computational Fluid Dynamics (CFD) software allow finding an expression of the material temperature at the depositing needle's exit as a function of the abovementioned variables. The obtained function describes the experimental equipment's behavior and has an average relative error of 12.6 % compared with the measured material's temperature at the depositing needle's exit. This proposal is expected to summarize the evidence of the CSE's potential for powering some manufacturing systems to obtain consumer goods and that a melt casting system mainly powered by CSE will be plausible shortly.

Scaling-Up for the Counter-Rotating Twin Screw Extrusion of Polymers.

A novel and original computer scaling-up system for the counter-rotating twin screw extrusion of polymers was developed. In the system, each scaling parameter (scaling criterion) may be considered as an objective function to be minimized for the single parameters or the functional relationships along the length of the screw. Scaling was based on the process simulation, which was performed using the comprehensive (or global) counter-rotating twin screw extrusion program called TSEM (Twin Screw Extrusion Model). The extrusion process was scaled by applying GASESTWIN (Genetic Algorithms Screw Extrusion Scaling) software developed for this purpose using genetic algorithms. Scaling up the extrusion process was carried out to enhance extrusion process throughput according to the scaling criteria specified by the single quantities of polymer melt temperature at the die exit and relative melting length, and by distributions along the screw length of the extrusion parameters of the polymer melt temperature and polymer plasticating. The global objective function had the lowest value for the selected extrusion parameters, which means the minimal differences between the values of the scaled-up processes and extrusion throughput was significantly increased. The solution to the problem of scaling the counter-rotating process presented in this paper complements the existing solutions for optimizing and scaling basic variants of the extrusion process, i.e., flood-fed and starve (metered)-fed single-screw extrusion, as well as co-rotating and counter-rotating twin-screw extrusion.

Additive manufacturing of flexible thermoplastic polyurethane (TPU): enhancing the material elongation through process optimisation

AbstractThermoplastic polyurethane (TPU) is used to produce elastomeric parts with superior wear/abrasion resistance, toughness, shock absorption properties, and flexibility, even at low temperatures. The production of this material through additive manufacturing (AM) techniques has been increasing because of the possibility of tuning the mechanical properties using structural design and build process parameters. Despite the data being limited, TPU produced by AM, mainly based on material extrusion, is much stiffer than the corresponding produced by conventional manufacturing, and, therefore, it shows a limited elongation. This study presents the mechanical characterization of TPU produced by the infrared light powder bed fusion (PBF-IrL) system (HP multi-jet fusion), which has recently been introduced. The properties are compared with TPU produced by open (3ntrA4) and closed (Markforged) material extrusion (MEX) systems. For the open FDM, the effects of the processing conditions are investigated to improve the material elongation and UTS with respect to the data reported in the literature for AM and conventional manufacturing. For this reason, an extensive and comprehensive review has been carried out. Compared to material extrusion, PBF-IrL TPU specimens showed higher Young’s modulus, but poorer A%. Considering the samples produced by MEX and compared to previous results in the literature, the properties obtained in this study are superior both in terms of UTS and A%.

Constructing In situ microfibrillar PA6/PLA composites with high strength and high toughness by a strong shear flow field

In situ microfibrillar PA6/PLA composites (MFCs) with high strength and toughness were produced via a multistage stretching extrusion system. The PA6 microfibrils induced the growth of PLA crystals perpendicular to the PA6 microfibrils and significantly enhanced the mechanical properties of the MFCs. Notably, the PLA-9 sample with 9 wt% PA6 microfibrils achieved excellent tensile strength and elongation at break (79.1 MPa and 77.8 %, respectively), which were 1.3 and 13.4 times than those of neat PLA. During the tensile process, the PA6 microfibrils underwent plastic deformation accompanied by the detachment and fragmentation of the PLA lamellae.

Artificial Intelligence-Assisted Fabrication of 3D Printed Technology in Pharmaceutical Development and Its Application

The concept of personalized medicine tailored to individual patients has garnered considerable attention recently, particularly in exploring the potential of 3D printing technology within the pharmaceutical and healthcare industries. 3D printing involves the layer-by-layer creation of three-dimensional objects from digital designs. This review aim to provide an in-depth discussion focusing on 3D printing technology, its role in drug delivery systems, and its application in the pharmaceutical product development process. Commonly categorized by material layering methods, 3D printers typically fall into inkjet, extrusion, or laser-based systems. The review delves into these different types of 3D printers and their diverse applications in drug delivery across various sectors. Additionally, it encompasses a selection of recent research conducted in the pharmaceutical realm concerning 3D printing for drug delivery applications and challenges. Keywords: 3D printed formulation, Laser based printing, inkjet printing, extrusion-based printing

Evaluating the performance of Bi58Sn42 mold produced by material extrusion additive manufacturing system for agile manufacturing

PurposeThe purpose of this study is to produce a low-cost sheet metal forming mold made from the low melting point Bi58Sn42 (bismuth) alloy by using an open-source desktop-type material extrusion additive manufacturing system and to evaluate the performance of the additively manufactured mold for low volume sheet metal forming. Thus, it was aimed to develop a fast and inexpensive die tooling methodology for low-volume batch production.Design/methodology/approachInitially, the three-dimensional printing experiments were performed to produce the sheet metal forming mold. The encountered problems during the performed three-dimensional printing experiments were analyzed. Accordingly, both tunings in process parameters (extrusion temperature, extrusion multiplier, printing speed, infill percentage, etc.) and customizations on the extruder head of the available material extrusion additive manufacturing system were made to print the Bi58Sn42 alloy properly. Subsequently, the performance of the additively manufactured mold was evaluated according to the dimensional change that occurred on it during the performed pressing operations.FindingsResults showed that the additively manufactured mold was rigid enough and proved to have sufficient strength in sheet metal forming operations for low-volume production.Originality/valueAlternative mold production was carried out using open-source material extrusion system for low volume sheet metal part production. Thus, cost effective solution was presented for agile manufacturing.

Light-based and cost-effective bioprinting of musculoskeletal GelMA constructs enriched with mesoporous bioactive glass nanoparticles

Bioprinting represents a promising technique for fabricating three-dimensional (3D) constructs with high-resolution and controlled architecture. However, many bioprinting technologies rely on expensive extrusion systems, which may compromise cell viability due to harsh processing conditions. This study presents the fabrication and characterization of musculoskeletal tissue in gelatin methacryloyl [GelMA]-based nanocomposite 3D constructs (comprising GelMA and mesoporous bioactive glass nanoparticles [MBGNs]) using a cost-effective, light-based bioprinting (LBB) system. We demonstrated that our strategy can produce high-resolution constructs (approximately 250 μm) while maintaining high cell viabilities (above 85%) for extended periods (weeks of culture). Furthermore, the nanocomposite constructs could facilitate the maturation of musculoskeletal tissue derived from C2C12 cells, as indicated by assessments of cell viability, elongation, and alignment over time. Our results suggested that the bioprinting approach outlined in this study allows for precise control of architecture, while creating a conducive environment for cell growth and tissue formation. These findings also highlighted the potential of the proposed LBB system to advance musculoskeletal tissue engineering for regenerative medicine applications.

Rational Design of a Triple-Layered Coaxial Extruder System: in silico and in vitro Evaluations Directed Toward Optimizing Cell Viability.

Biofabrication is a rapidly evolving field whose main goal is the manufacturing of three-dimensional (3D) cell-laden constructs that closely mimic tissues and organs. Despite recent advances on materials and techniques directed toward the achievement of this goal, several aspects such as tissue vascularization and prolonged cell functionality are limiting bench-to-bedside translation. Extrusion-based 3D bioprinting has been devised as a promising biofabrication technology to overcome these limitations, due to its versatility and wide availability. Here, we report the development of a triple-layered coaxial nozzle for use in the biomanufacturing of vascular networks and vessels. The design of the coaxial nozzle was first optimized toward guaranteeing high cell viability upon extrusion. This was done with the aid of in silico evaluations and their subsequent experimental validation by investigating the bioprinting of an alginate-based bioink. Results confirmed that the values for pressure distribution predicted by in silico experiments resulted in cell viabilities above 70% and further demonstrated the effect of layer thickness and extrusion pressure on cell viability. Our work paves the way for the rational design of multi-layered coaxial extrusion systems to be used in biofabrication approaches to replicate the very complex structures found in native organs and tissues.

Design, calibration and performance evaluation of a small-scale 3D printer for accelerating research in additive manufacturing in construction

3D printing in construction presents numerous advantages, such as geometric flexibility, potential cost and time savings, the incorporation of recycled and sustainable materials, and reduced waste, thereby reducing the construction sector's environmental impact. Despite these advantages, the widespread adoption of AM in construction faces hurdles, primarily due to the prohibitive costs of large-scale concrete printers — typically ranging from $180,000 to over $1 million — and technological constraints that impede research and development efforts within the construction sector. To address these challenges, our study focuses on designing, developing, calibrating and evaluating an affordable lab-scale 3D printer specifically tailored for cement-based materials, aiming to lower the entry barrier for AM research in construction. This paper presents a proof-of-concept for a simple, yet functional printing technology that meet the requirements for research studies. The study details the development process, from the conceptual design to the calibration of printing parameters. The development process included the assessment of preliminary extrusion system designs integrated with the motion systems of a fused deposition modeling 3D printer. Subsequently, material studies were carried out to determine optimal material mix compositions and ratios. A comprehensive calibration of printing parameters using statistical analysis was proposed to ensure consistent and quality printing. The printability and applicability of the proposed small-scale 3D printer were assessed by printing samples and testing their thermal properties. Cost analysis showed that the proposed 3D printer, costing $273, offers benefits compared to existing market alternatives. The study illustrates the potential of small-scale 3D printers to facilitate construction research and practices, thereby promoting the development of sustainable construction methods.

Significance of variable thermal conductivity and suction/injection in unsteady MHD mixed convection flow of Casson Williamson nanofluid through heat and mass transport with gyrotactic microorganisms

AbstractThe present paper explores a two‐dimensional mixed bio‐convective unsteady viscous hydro‐magnetic Casson Williamson nanofluid flow model with heat and mass transport incorporating motile microorganisms towards a stretchy spinning disc. The flow concept is accomplished by rotating a stretched disc with a time‐varying angular velocity. By applying a magnetic field normal to the axial direction, a magnetic interaction is taken into consideration. The Casson Williamson nanofluid contains nanosized particles suspended with swimming motile microorganisms and the rotation of the disc is exhibited by buoyancy forces, thermophoresis, suction/injection, zero mass flux conditions, variable thermal conductivity, Joule heating and so forth. The obtained flow narrating differential equations of the model are transformed into ordinary differential system. This is accomplished by simulating boundary value problems using the shooting technique using the ‘ND‐Solve’ approach included in the Mathematica software (Mathematica 12). The implications of the engaged parameters such as Williamson fluid parameter, Casson fluid (CF) parameter, thermophoresis parameter, Brownian motion parameter and so forth, on both axial and radial velocities, temperature, concentration of nanoparticles and microorganisms are explained by means of graphical and tabular constructions. This paper's validity has been confirmed and its findings align with those of other previously published papers. Furthermore, it is found that both the axial and radial velocity profiles are seen to be diminishing functions of the CF parameter. The identified observation may have theoretical implications for a number of engineering procedures, solar energy systems, biofuel cells and extrusion system improvement. Moreover, this work finds application in micro‐fabrication techniques and the chemical industry.

Design, modeling and feedforward control of a hybrid extruder for material extrusion additive manufacturing

Material extrusion (MatEx) is the one of the most widely utilized additive manufacturing (AM) methods. The key to high printing quality in MatEx lies in the synchronization between the fast motion system and the slow extrusion system. However, the synchronization is challenged by the slow response of the extrusion system. In MatEx, there are two main types of extrusion systems: Bowden and direct-drive (DD), based on different extruder-hot end arrangements. DD systems have the extruder installed directly above the hot end, providing a relatively fast extrusion response but adding more inertia to the print head. In contrast, Bowden systems position the extruder on the printer’s frame, feeding the filament to the hot end through a long Bowden tube. As a result, this setup leads to a sluggish extrusion response due to the elasticity of the long segment of filament but has a lower print head’s inertia, offering a higher positioning accuracy compared to the DD system. To leverage the advantages of both extrusion systems, this paper proposes a hybrid extrusion system design that combines a Bowden extruder with a low-mass DD extruder for filament feeding. To optimize the design and control of the extruder, a low-order model that characterizes the hybrid extruder dynamics is proposed. The model is used to design a feedforward (FF) controller that minimizes the force exerted by the DD extruder motor in the hybrid extruder while achieving the desired extrusion accuracy. The effectiveness of the proposed extruder and the FF controller is validated experimentally by demonstrating transient responses as fast as those of the standard DD extruder with up to 65% less force required from the DD extruder motor. Data collected from motor torque–mass specifications of three motor series from three different manufacturers indicate that the torque/force reduction could yield up to a 69% mass reduction in the motor used for the DD extruder, adding only 32.5% extra weight of the hot end to the print head. Hence it holds the potential to achieve the same extrusion accuracy as standard DD extruders while significantly reducing print head inertia, hence the resulting vibration of the printer, as demonstrated using a case study.

Joint Prescriptive Maintenance and Production Planning and Control Process Simulation for Extrusion System

Production planning and control (PPC) is the mainstay of every manufacturer and ensures flawless production processes. However, PPC is jeopardized by breakdowns that can only be tackled with appropriate maintenance. In the past, static strategies, such as reactive and scheduled maintenance, have been used. Yet, with growing system complexity, Industry 4.0, and abundant sensor data, dynamic strategies through PHM have emerged. The most advanced maintenance strategy is prescriptive maintenance (PxM), which allows manufacturers not only to predict failures but also to establish condition-based production plans and controls. To this end, our study explores the integration of PxM with PPC. First, we propose a fault prediction model based on health indicators and future loads of a single-machine system. The proposed fault prediction is integrated into a joint PxM and PPC simulation model that compares the make­span of three joint PxM and PPC strategies inter se and versus reactive and scheduled maintenance. A simulation study using industrial data from an extrusion process evaluates the different strategies across different time horizons (one month to a year). The findings indicate that joint PxM and PPC outperform other strategies, providing significant time savings over traditional methods. Further, a sensitivity analysis is conducted to assess the robustness of the PxM strategies under varying levels of measurement noise, revealing potential challenges under high noise conditions. The study contributes to the field of PHM by providing insights into the effectiveness of joint PxM and PPC strategies and offering a comprehensive analysis of their performance under different conditions.

DESIGN AND FABRICATION OF CIVIL 3D PRINTER

The advent of 3D printing technology has revolution- ized the construction industry, offering innovative so- lutions for rapid, cost-effective, and sustainable build- ing practices. This research paper presents a compre- hensive study on the manufacturing and fabrication of a 3D concrete printer tailored for large-scale construc- tion applications. The paper outlines the design princi- ples, mechanical and electrical systems, material con- siderations, and software integration necessary for the development of an efficient and reliable 3D concrete printer. Key components of the printer, including the frame, extrusion system, and control mechanisms, are meticulously designed to ensure precision, stability, and durability. Advanced materials such as high- performance concrete mixes are formulated to meet the unique requirements of 3D printing, balancing workability, strength, and setting time. The integration of sensors and automation technology facilitates real- time monitoring and control, enhancing the accuracy and consistency of the printed structures. The implementation phase involved extensive testing and validation, highlighting the printer’s capability to construct complex geometries and large-scale ele- ments with minimal human intervention. Results indi- cate significant improvements in construction speed, cost savings, and material efficiency compared to tra- ditional methods. The paper concludes with a discus- sion on potential applications, challenges, and future directions for 3D concrete printing technology in the construction industry.

DEVELOPING AN EXTRUDER MACHINE OPERATING SYSTEM THROUGH PLC PROGRAMMING WITH HMI DESIGN TO ENHANCE MACHINE OUTPUT AND OVERALL EQUIPMENT EFFECTIVENESS (OEE)

Designing a state-of-the-art PLC-based extrusion machine with a user-friendly HMI ensures seamless operation, enhancing Overall Equipment Effectiveness (OEE). This project focuses on automating an extrusion system with advanced technologies for optimized functionality and reliability. The architecture includes sophisticated components to boost productivity and product quality. Key aspects involve orderly control and synchronization of the extruder motor, feeder motor, lubrication pump, and vacuum pump for consistent performance with precise temperate profile. A significant innovation is the centralized blower system for machine temperature profile analysis and control, replacing individual controllers to enhance thermal management efficiency and ensure uniform temperature distribution. A high-low temperature alarm system alerts operators to deviations, maintaining process stability. Real-time data on current (Amps) and frequency (Hz) is displayed on the HMI from the inverter for monitoring and diagnostics. The system also features machine downline controlling capabilities for efficient management of downstream processes. Collectively, these innovations create a robust, efficient, and user-friendly extrusion machine that enhances OEE and product quality.

Effects of high gravity on properties of parts fabricated using material extrusion system by additive manufacturing

Additive manufacturing (AM) has gained significant attention in recent years owing to its ability to fabricate intricate shapes and structures that are often challenging or unattainable using conventional manufacturing techniques. This high-quality development trend entails higher requirements for the structural design of 3D printers. In this study, polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS) filaments were fed through a heated extrusion nozzle, which melted the material and deposited it onto a build platform. This study's objectives are high-gravitational material extrusion (HG-MEX) systems development, analyzing the high gravity influences on the flow behavior of materials during extrusion, and understanding the effects of gravitational on material flow and overall extrusion performance. HG-MEX systems have great potential for addressing various challenges in additive manufacturing, such as precise manufacturing. The highlight of the progress is that we developed an HG-MEX system and applied surface science to material extrusion in different gravity. We established a system and obtained results on different gravity, we analyzed the analogy between different gravity phenomena. We analyzed the interplay between the behavior of the fabricated parts and gravity. We analyzed high gravity effects on extrusion processes. The results confirmed the characteristics and feasibility of the developed system. The results suggest that a material extrusion line operating under 15 G conditions resulted in better printing quality compared to one operating under 1 G conditions. This observation implies that high gravity had a positive effect on the extrusion process, leading to improved material extrusion performance.

Thermal and Entropic analyses of free convection of nanofluid in a partially heterogeneous porous chamber using the two-phase mixture model

Entropy generation and convection heat transfer in a partially porous chamber with different side wall temperatures using CuO–H2O have been investigated. The importance of this issue is wide application of the results in solar collectors, thermal extrusion systems, heat exchangers, bio-medicine, nuclear waste disposal, etc. The innovation of the present work is related to the investigation of fluid and heat fields and entropy generation by using a matrix with subordination of porosity to the vertical axis and permeability, thermal conductivity, and viscosity with subordination of porosity. To obtain accurate results, the two-phase mixture model was used, and thermal conductivity and viscosity of nanofluid were simulated by experimental models by temperature and volume fraction dependence. Governing equations are solved by the FVM. The main findings indicate that the best and worst optimization factor will occur in the porous matrix ε = ε(y2) and ε = -ε(y2), respectively, which is 113 % and 86 % of NH of the homogeneous matrix, respectively. Also increasing the filling of the cavity, highly improves NH, so that the NH will reach from 1.19 to 1.82 with the increase of S from 0.25 to 1.

Dimensional accuracy of acrylonitrile butadiene styrene and polylactic acid samples printed in vacuum-assisted material extrusion system

This paper discusses the impact of integrating a vacuum system into a material extrusion 3D printing process for acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA) materials. The study aimed to investigate the effect of a vacuum system on the dimensional accuracy of the printed samples. Upon completion of the printing process, the samples’ dimensions were carefully assessed using a Coordinate Measuring Machine (CMM). The geometrical dimensions measured are the diameter, corner radius, fillet, thickness, width, length and angle. Based on the result obtained, the material has yet to reach 100% of the desired geometry, which was identified due to the shrinkage of the material after the printing process. The results show that the vacuum system improved material flow and reduced dimensional deviations by reducing air molecules and minimizing convection. The results indicated a significant enhancement in dimensional accuracy for both ABS and PLA samples when using the vacuum system. ABS samples showed a 4% increase in accuracy, while PLA samples exhibited a 2% improvement compared to samples printed without vacuum assistance. These improvements were achieved by optimizing process parameters such as layer height (0.15 mm), infill percentage (10%), printing speed (45 mm s−1), and bed temperature (60 °C). These parameters were selected to ensure finer details, improved precision, structural support, stability, better adhesion, and reduced warping.

Functionally graded hydrogels with opposing biochemical cues for osteochondral tissue engineering.

Osteochondral tissue (OC) repair remains a significant challenge in the field of musculoskeletal tissue engineering. OC tissue displays a gradient structure characterized by variations in both cell types and extracellular matrix components, from cartilage to the subchondral bone. These functional gradients observed in the native tissue have been replicated to engineer OC tissuein vitro. While diverse fabrication methods have been employed to create these microenvironments, emulating the natural gradients and effective regeneration of the tissue continues to present a significant challenge. In this study, we present the design and development of CMC-silk interpenetrating (IPN) hydrogel with opposing dual biochemical gradients similar to native tissue with the aim to regenerate the complete OC unit. The gradients of biochemical cues were generated using an in-house-built extrusion system. Firstly, we fabricated a hydrogel that exhibits a smooth transition of sulfated carboxymethyl cellulose (sCMC) and TGF-β1 (SCT gradient hydrogel) from the upper to the lower region of the IPN hydrogel to regenerate the cartilage layer. Secondly, a hydrogel with a hydroxyapatite (HAp) gradient (HAp gradient hydrogel) from the lower to the upper region was fabricated to facilitate the regeneration of the subchondral bone layer. Subsequently, we developed a dual biochemical gradient hydrogel with a smooth transition of sCMC + TGF-β1 and HAp gradients in opposing directions, along with a blend of both biochemical cues in the middle. The results showed that the dual biochemical gradient hydrogels with biochemical cues corresponding to the three zones (i.e. cartilage, interface and bone) of the OC tissue led to differentiation of bone-marrow-derived mesenchymal stem cells to zone-specific lineages, thereby demonstrating their efficacy in directing the fate of progenitor cells. In summary, our study provided a simple and innovative method for incorporating gradients of biochemical cues into hydrogels. The gradients of biochemical cues spatially guided the differentiation of stem cells and facilitated tissue growth, which would eventually lead to the regeneration of the entire OC tissue with a smooth transition from cartilage (soft) to bone (hard) tissues. This promising approach is translatable and has the potential to generate numerous biochemical and biophysical gradients for regeneration of other interface tissues, such as tendon-to-muscle and ligament-to-bone.