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Journal articles on the topic 'Extruder geometry'
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1
Kocserha, István, and Ferenc Kristály. "Effects of Extruder Head’s Geometry on the Properties of Extruded Ceramic Products." Materials Science Forum 659 (September 2010): 499–504. http://dx.doi.org/10.4028/www.scientific.net/msf.659.499.
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A plastic brick clay with high clay mineral content was selected and the effects of different extruder heads on the main physical properties of the extruded products were investigated. The raw material was processed by a laboratory extruder after homogenization and wetting. Extruder heads with conical and special (spherical and torus) inner shape were applied to form and produce the green products which were examined after drying and firing. The rotation of the extruder screw was also varied between 15-55 1/min. Applying optical microscopy and SEM, the structure of the green products was analyzed. In addition to the physical properties of the products, the pressure caused by the extruder heads was determined by theoretical calculation and measurement. The results revealed that the physical properties of the products could be changed only by changing the shaping die geometry when the product size and production method remained unchanged. Maximal compressive strength of fired brick products (35.45 MPa) was obtained in case of the spherical head while the use of torus head caused some 5% decrease in the power consumption of the extruder. The density of fired products decreased and water adsorption increased when the rotation speed of the extruder screw was increased. The measurements confirmed the theoretical order of the applied extruder heads in terms of capability of pressure generation.
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Malik, M., and D. M. Kalyon. "3D Finite Element Simulation of Processing of Generalized Newtonian Fluids in Counter-rotating and Tangential TSE and Die Combination." International Polymer Processing 20, no. 4 (August 1, 2005): 398–409. http://dx.doi.org/10.1515/ipp-2005-0068.
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Abstract A full three-dimensional finite element analysis of the nonisothermal flow of generalized non-Newtonian fluids in counter-rotating tangential twin screw extruder is presented. Previous studies of the simulation of processing in tangential twin screw extruders have focused solely on the twin screw extruder, whereas here the coupled flow and heat transfer occurring in the integrated geometry of the extruder, connected to a die are considered. The FEM based numerical simulation of the coupled momentum-mass-energy conservation equations allowed the determination of the effects of some of the important system parameters, including the power law index and the staggering angle of the screws, on the pumping and pressurization capability of the extruder and the associated degree of fill in the extruder.
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Kadyirov, Aidar, Rustem Gataullin, and Julia Karaeva. "Numerical Simulation of Polymer Solutions in a Single-Screw Extruder." Applied Sciences 9, no. 24 (December 11, 2019): 5423. http://dx.doi.org/10.3390/app9245423.
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Single-screw extruders are the most common equipment used for polymer extrusion. The study of the hydrodynamics of a polymer melts flow in the extruder channel is the basis for modeling and understanding the extrusion process. In general form, the extruder includes a straight section with a screw installed in it. In this study, the three-dimensional mathematical modeling of the polymer solutions flow in the metering zone of a single-screw extruder is performed. The influences of the screw geometry (L/D2 = 1…3) on the flow structure and the pressure drop are analyzed under a speed rotation up to 60 rpm. Aqueous solutions of 0.5% polyacrylamide (0.5% PAA) and 1.5% sodium salt of carboxymethyl cellulose (1.5% CMC) are considered as the working fluid.
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Sikora, Janusz W., and Tomasz Garbacz. "The effect of the geometry of extrusion head flow channels on the adiabatic extrusion of low density polyethylene." Journal of Polymer Engineering 35, no. 6 (August 1, 2015): 605–10. http://dx.doi.org/10.1515/polyeng-2014-0276.
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Abstract Plastics extrusion can be divided into the following types: conventional extrusion (run at low speed of the rotating screw), adiabatic extrusion (screw speed is relatively high, yet the process requires the use of heaters) and high speed extrusion (extruder barrel requires cooling due to very high screw speeds). This paper presents the results of a study undertaken to investigate the adiabatic extrusion of low density polyethylene using heads with circular cross-section nozzles and different geometries of flow channels. In the experiments, we examined the temperature and pressure of the polymer in the plasticizing unit, as well as the relationships between the output, thermal power conveyed by the plastic, total power supplied to the extruder, extrusion efficiency, unit consumption of the total energy supplied to the extruder as well as the rotational speed of the screw and the extruder’s head geometry. It was found that the most favorable energy conditions, i.e., the highest efficiency of the adiabatic extrusion of low density polyethylene in the whole range of the tested screw speeds, are ensured when the head with the highest diameter and length nozzle is applied.
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Thieleke, Philipp, and Christian Bonten. "Enhanced Processing of Regrind as Recycling Material in Single-Screw Extruders." Polymers 13, no. 10 (May 11, 2021): 1540. http://dx.doi.org/10.3390/polym13101540.
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Regrind processing poses challenges for single-screw extruders due to the irregularly shaped particles. For grooved feed zones, the output is lessened by the reduction of bulk density in comparison to virgin material. Simultaneously, the melt temperature increases, reducing the extruder’s process window. Through experimental investigations on a test stand, a novel feed zone geometry (nominal diameter 35 mm) is developed. It aligns the regrind’s specific throughput with that of virgin material. The regrind processing window is essentially increased. As the solids conveying in the novel feed zone cannot be simulated with existing methods, numerical simulations using the discrete element method are performed. Since plastic deformation occurs in the novel feed zone geometry, a new hysteresis contact model is developed. In addition to spheres, the regrind and virgin particles are modeled as superquadrics to better approximate the irregular shape. The new contact model’s simulation results show excellent agreement with experimental compression tests. The throughput of the extruder simulations is considerably underestimated when using spheres to represent the real particles than when using irregularly shaped superquadrics. Corresponding advantages can be seen especially for virgin material.
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Camesasca, M., I. Manas-Zloczower, and M. Kaufman. "Influence of extruder geometry on laminar mixing: entropic analysis." Plastics, Rubber and Composites 33, no. 9-10 (November 2004): 372–76. http://dx.doi.org/10.1179/174328904x24853.
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Wang, Ping, Xiao Yang Shen, and Xian Liang Zong. "Optimum Design on Trapezoidal Thread Parameters of Co-Rotating Twin Screw Extruder." Advanced Materials Research 97-101 (March 2010): 245–49. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.245.
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In order to design trapezoidal thread parameters of co-rotating twin screw extruder that is used in non-fused materials processing, based on geometry of fully wiped co-rotating twin screw extruder by M. L. Booy, the paper adopts tangential approximation method to determine the parameters of trapezoidal thread choosing tangent of especial point of normal section curve. And reasonable spans of oblique angle, actual top width of flight, channel depth and thread lead are determined by the optimum design with objective function of maximal theoretical flux. Experiments show that a co-rotating twin screw pulping extruder of trapezoidal thread designed by the method is easier to machine and measure, and pulp processed by the twin screw pulping extruder can meet the quality requirements. Thus, twin screw designed by the method reserves the main strongpoint of the fully wiped co-rotating twin screw extruder.
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Karunakaran, K. P., and S. G. Dhande. "Computer aided design of cutters for helicoidal surfaces." Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture 212, no. 5 (May 1, 1998): 373–82. http://dx.doi.org/10.1243/0954405981515978.
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The design of cutters is an important consideration for the manufacture of helicoidal surfaces such as extruder screw surfaces. These surfaces are produced mostly by milling processes using form cutters of end mill type, side mill type or disc type, such as side-and-face mill or grinding wheel. The methodology proposed in the paper addresses the problem of the design of cutters for the machining of helicoidal surfaces. Using the proposed methodology, the characteristic profile(s) of the cutter can be determined from the given cross-sectional profile and lead of a helicoidal surface. By sweeping this characteristic profile along an appropriate path or around an axis, the geometry of the specific form cutter can be obtained. Such a geometry could be a turning tool, an end mill, a side mill, a side-and-face mill or a grinding wheel, depending on the process adopted for manufacture. The proposed methodology can also be used to determine the geometry of the helicoidal surface that will be obtained by using a given cutter. In the paper, the procedure to obtain the geometry of the cutters for machining extruder screws is explained with illustrations.
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Miloš Matúš, Juraj Beniak, Peter Križan, and Ľubomír Šooš. "Mathematical design theory of screw extruder used for additive manufacturing." Global Journal of Engineering and Technology Advances 5, no. 3 (December 30, 2020): 059–68. http://dx.doi.org/10.30574/gjeta.2020.5.3.0113.
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Additive manufacturing as the technology of the future brings new challenges. One of them is the economic efficiency of production. This paper focuses on the mathematical analysis and structural design of extrusion screw used for additive manufacturing. The primary objective is to analyze the screw tool geometry and determine a procedure for its design, specifically the theory involved with the pressing tool and force relations which are necessary for the verification of the proposed tool geometry and its strength analysis. Procedures for determining frictional performance of the screw press are used in designing the drive of the screw extruder of 3D printer. Familiarity with the above mentioned procedures forms the basis for research into new tool - screw that will improve the service life and competitiveness of the technology.
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Kelly, A. L., E. C. Brown, and P. D. Coates. "Melt temperature field measurement: influence of extruder screw and die geometry." Plastics, Rubber and Composites 34, no. 9 (November 2005): 410–16. http://dx.doi.org/10.1179/174328905x72003.
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Dixit, Ankit, and Vikash Kumar. "Miniature pellet extruder concept for robotic 3D printing application." IAES International Journal of Robotics and Automation (IJRA) 11, no. 2 (March 2, 2022): 161. http://dx.doi.org/10.11591/ijra.v11i2.pp161-167.
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<span>Additive manufacturing more commonly known as 3D printing has been in the limelight of manufacturing research for a long. Many advances have been made in the past in elementary printing techniques, materials, and post-processing schemes. In this paper, a concept of a miniature pellet extruder is added at the end of the articulated robotic arm. The idea is to create a system that capable to print larger and more complex shapes of any parts with the help of a low payload capacity robotic arm and provide output as a single-piece structure. It also helps to print and handle objects with larger and more complex geometry with an optimized cycle time. Knowledge from this research work will also help to choose not only the right low payload capacity robotic arm, but also provides a logical approach for selecting a pellet extruder over a filament extruder.</span>
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Winck, J., and S. Frerich. "Numerical Simulation of Fluid Flow and Mixing Dynamics inside Planetary Roller Extruders." International Polymer Processing 36, no. 5 (November 1, 2021): 508–18. http://dx.doi.org/10.1515/ipp-2020-4084.
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Abstract In this contribution, the fluid flow and mixing dynamics inside planetary roller extruders are simulated using the finite element method (FEM) and the mesh superposition technique (MST). Three-dimensional configurations with planetary spindles of varying number and geometry of planetary spindles were created to analyse the influence of the spindle configuration and the rotational speed on the process behavior. Therefore, pressure gradients, flow velocities and directions, shear rates, the mixing index and residence time distributions were evaluated. The distributive and dispersive mixing efficiencies varied depending on the planetary spindle configuration, and these configurations thus suit different processing tasks. In comparison to the standard planetary spindles, the TT3 spindles, with their incomplete toothing, and the knob spindles, with their double transversal helical toothing, showed intense axial and radial mixing. In general, the mixing performance of the planetary roller extruder is explained by a high rate of extensional flow and frequent changes in flow type. The reported numerical approach allows, for the first time, a comprehensive observation of the process behavior of planetary roller extruders.
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Maia, J. M., O. S. Carneiro, A. V. Machado, and J. A. Covas. "On-Line Rheometry for Twin-Screw Extrusion (Along the Extruder) and its Applications." Applied Rheology 12, no. 1 (February 1, 2002): 18–24. http://dx.doi.org/10.1515/arh-2002-0002.
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Abstract Due to a number of practical difficulties, both in- and on-line measurements of the rheological properties of complex systems during extrusion are usually performed at the end of the extruder, under very specific experimental conditions. This makes this type of instruments more useful for quality control than for process optimisation, since information about the influence of the geometry and/or processing conditions on the evolution of the material characteristics inside the extruder is not easily gathered. Recently, however, the authors have developed an on-line capillary rheometry system that overcomes most of the existing problems and allows small amounts of sample to be tested in very near real time, along the extruder. The present work aims at illustrating the usefulness of this concept for the study of physical compounding processes and some reactive systems. Two very different systems will be used for that purpose: a reactive extrusion process (the peroxide-induced thermal degradation of polypropylene) and the dispersive mixing involved in the preparation of thermoplastic/carbon fibre composites.
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Pongmuksuwan, Pornlada, and Wanlop Harnnarongchai. "The Smart Blending for Multilayer Structure of PLA/EVOH." Key Engineering Materials 751 (August 2017): 258–63. http://dx.doi.org/10.4028/www.scientific.net/kem.751.258.
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The concept of smart blender to form a multilayer structure of PLA/EVOH has been developed. Unlike conventional mixing, smart blending provides a formation of multilayer structure by dictating the motion of stir rod to agitate melts. The PLA and EVOH are supplied separately by a single-screw extruder. An experimental rig is assembled at the end of a co-extruder, and melt from an extruder entered an experimental rig via a cylindrical port. The molten EVOH is recursively stretched and folded in an experimental rig of PLA major phase to give an alternating layer structure. The rod is rotated by variable speed motor that is independently controllable. The rod rotational speed and volumetric flow rates of EVOH and PLA are of our interest. Careful design of stir rod in smart blending is necessary for effective performance. The computational model provided the visualization of flow profile inside an experimental rig. The simulation determined the geometry of the stir rod required to achieve the spiral flow developed of the melt. The experimental results suggest that the injected streams of EVOH are stretched and folded to multiple and distributed layers ranging thickness from 10 to 200 um. The characteristic folding of EVOH melt depends on the volumetric flow rate of the screw extruder and rod rotational speed. However, the coalescence of EVOH layers is observed for high rod rotational speed.
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Zhang, Bing, Xiao Feng Liu, and Chao Bi. "Extrusion Uniformity Optimization for Shaping Channel Design in Large-Scale Die-Plate of Underwater Pelletizing." Applied Mechanics and Materials 275-277 (January 2013): 562–66. http://dx.doi.org/10.4028/www.scientific.net/amm.275-277.562.
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As an important component of large-scale extruder system for polymer material, Die-plate can be regarded as the final determinant for pelletization uniformity. Polymer melt was shaped in shaping channels and extruded from die-holes from Die-plate and then be diced. The design of shaping channels directly influences the uniformity for polymer-melt extrusion pressure and extrusion velocity of different die holes. In this paper, a three-dimensional flow model for polymer flow in Die-plate channel was presented, and then finite element simulation was used to analyze the distribution of extrusion velocity in each die-hole. Based on simulation result, a BP neural network model was applied to analyze the relationship between geometry factors of Die-plate, such as length of shaping channels, die hole extrusion velocity distribution, and extrusion uniformity. This optimization method can be used in the design of Die-plate to improve effect and quality of actual polymer production and processing.
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Stevenson, J. F. "Newtonian Simulation and Dimensional Control of the Single Roller Die Extrusion Line." Rubber Chemistry and Technology 59, no. 4 (September 1, 1986): 651–65. http://dx.doi.org/10.5254/1.3538226.
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Abstract A single roller die consists of a fixed plate die bounded on one edge by a rotating cylinder. Material is forced through the die by a combination of pressure flow from an extruder and drag flow by the roller. Extrusion lines for tire components have traditionally been controlled by manipulating the size (cross-sectional area) of the extrudate through adjustments of the line speed relative to the screw speeds for cold-feed extruders or feed-strip widths and/or mill speeds for hot-feed extruders. Intentional changes in shape (ratios of dimensions normalized for size change) required altering the die geometry. Sources of variation in size and shape during extrusion include transients during start up, property changes within and between batches, short-term cycling of output rate, temperature cycling and drift, and inadequate control of independent variables such as screw and line speeds. The objective of this paper is to demonstrate how a single roller die line can be used to control independently two categories of dimensions (e.g., thicknesses and widths). This independent control necessarily requires that at least two other variables be manipulated, in this case, screw speed and roller die speed.
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Subbotin, E. V., А. G. Shcherbinin, and Y. M. Hasyanova. "SELECTION OF RATIONAL GEOMETRY EXTRUDER SCREW FOR PROCESSING OF HEAT RESISTANCE POLYMER COMPOSITIONS." Scientific and Technical Volga region Bulletin 6, no. 4 (August 2016): 99–101. http://dx.doi.org/10.24153/2079-5920-2016-6-4-99-101.
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Isametova, Madina, Bakhyt Absadykov, Bauyrzhan Bazarbay, and Gulbarshyn Smailova. "Development of the design and technology of extrusion of metal-polymer mixtures for the production of feedstocks." Eastern-European Journal of Enterprise Technologies 4, no. 1 (118) (August 31, 2022): 23–33. http://dx.doi.org/10.15587/1729-4061.2022.259532.
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The paper is devoted to the development of new equipment for the production of metal-polymer thread. 3D printing with metal-polymer thread is one of the advanced directions in the technology of manufacturing metal parts of complex shape. The proposed technology is an alternative to the currently existing metal injection molding (MIM) technology and selective laser melting printing technology. An important step in this work was to conduct computational experiments to determine the effect of screw rotation on the process pressure parameter and the design of the main assembly of the screw extruder. As a result of the research, the pressures on the metal-polymer composition were determined depending on the rotation speed of the screw. With a rotation of 30 rpm, the pressure reached 0.05 Pa and the maximum pressure was 0.18 MPa. The experiments were carried out in the CradelSFlow program. The computer calculation showed a margin of the screw strength coefficient k=1.8, and a maximum deflection of 2.8∙10–4 m, which meets the condition of static rigidity. To determine the correct value of the gap δ between the screw ridge and the extruder walls, an analysis of the rotor dynamics was carried out. The result of this study is the critical extruder rotation speed of 60 rpm at which the phenomenon of precession may occur. Amplitude-frequency characteristics ydin=7∙10–4 m. According to the results of the dynamic calculation, the screw dimensions were adjusted, the geometry was reduced by ∆=0.5 mm. The experiments made it possible to verify the optimal parameters of the technological process of metal-polymer mixture extrusion. The data obtained are important for the improvement and development of 3D printing technology for metal parts of complex geometric shape.
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Wałęsa, Krzysztof, Jan Górecki, Maciej Berdychowski, Aleksandra Biszczanik, and Dominik Wojtkowiak. "Modelling of the Process of Extrusion of Dry Ice through a Single-Hole Die Using the Smoothed Particle Hydrodynamics (SPH) Method." Materials 15, no. 22 (November 20, 2022): 8242. http://dx.doi.org/10.3390/ma15228242.
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This article presents the outcome of research on modelling the process of the extrusion of crystalline dry ice. The purpose of this process is to densify the material and obtain pellets of several millimeters in diameter. This reduces the sublimation rate in ambient conditions of the material whose temperature in a solid state is 195 K. A lower sublimation rate means a reduction of the loss of product in its final applications, which include refrigeration and reduction of atmospheric emissions of gaseous CO2. A ram-type extruder was considered in this analysis, in which dry ice was extruded through a single-hole die of varying geometry. The article presents the results of numerical analyses of the extrusion process, using a simulation method based on the Smoothed Particle Hydrodynamics (SPH) approach. The results from simulations were verified by the experimental data in terms of the maximum force required to complete the process, in order to assess the applicability of the proposed method in further research on dry ice compression.
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Boparai, Kamaljit Singh, Rupinder Singh, and Harwinder Singh. "Process optimization of single screw extruder for development of Nylon 6-Al-Al2O3 alternative FDM filament." Rapid Prototyping Journal 22, no. 4 (June 20, 2016): 766–76. http://dx.doi.org/10.1108/rpj-09-2014-0119.
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Purpose The purpose of this study is to investigate the process parameters of a single-screw extruder for development of Nylon6-Al-Al2O3-based alternative fused deposition modeling process (FDM) feedstock filament (in lieu of commercial acrylonitrile butadiene styrene filament). The effect of major screw extruder parameters on the tensile strength of fabricated filaments has also been analyzed. Design/methodology/approach The Taguchi experimental log has been designed for investigating the significance of input parameters of screw extruders (such as mean barrel temperature, die temperature, screw speed, material composition and speed of take up unit) on the tensile strength of fabricated filaments. The suitability of alternative material as an FDM filament has been verified by rheological investigations. The tensile strength of an alternative feedstock filament has been investigated experimentally according to the ASTM-638 standard. The analysis was performed by the analysis of variance (ANOVA) method with the help of MINITAB 17 software. The stiffness of the FDM printed parts with nine different feedstock filaments (prepared by selecting nine different combinations of analytical parameters) was determined by dynamic mechanical analysis (DMA). Findings The tensile strength of the feedstock filament was significantly affected by the variation of major input parameters during the processing of alternative material on a single-screw extruder. The ANOVA shows that two process parameters (namely, material composition and die temperature) were significant at the 5 per cent level (“F” value 41 and 21.96, respectively) and remaining two (mean barrel temperature and screw speed) were insignificant at the 5 per cent level. Further, a linear regression model has been developed to predict the tensile strength of the alternative feedstock FDM filament. The results highlight that a deviation of <1 per cent was observed (in the tensile strength of nine sets of experimental runs) as compared to the predicted values of the regression model. In addition to above, the DMA result also indicates that the filament fabricated with optimum combination of parameters has highest stiffness and is more suitable for the FDM system. Research limitations/implications During the processing of alternative material in a single-screw extruder and FDM system, the increase of filler contents adversely affects the contact surfaces. Practical implications The FDM parts with customized properties (viz., thermal and tribological) can be fabricated with alternative feedstock filament material. Originality/value The potential to consider alternative filament material for FDM system includes rapid manufacturing of functional parts, tailor-made grinding tools for dentists and rapid tooling of metal matrix composites having complex geometry.
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Vergnes, Bruno. "Average Shear Rates in the Screw Elements of a Corotating Twin-Screw Extruder." Polymers 13, no. 2 (January 19, 2021): 304. http://dx.doi.org/10.3390/polym13020304.
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The rapid estimation of the average shear rate encountered by the material as it flows along the screw elements of a corotating twin-screw extruder is a key point for many applications. In this paper, two methods of evaluation are presented that allow the calculation of the average shear rate as a function of the screw geometry, feed rate, and screw speed. A comparison is made between the approximate and exact methods. It is shown that it is crucial to take into account the shear component due to the pressure flow, especially in the left-handed screw elements.
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Xu, Yi She, Xiong Hua Guo, and Hui Mei Kang. "Differential Shear-Compression Theory of Solids Conveying in Vane Extruder." Advanced Materials Research 753-755 (August 2013): 1377–81. http://dx.doi.org/10.4028/www.scientific.net/amr.753-755.1377.
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Based on the study of the solids conveying in the vane extruder, a new concept of the differential shear-compression theory is presented. The objective existing of shear and compressive forces is proved by the mathematical method. And the exerted force is proved to be depended on the compression displacement and the differential of compression speed when solid materials are transported in the solids conveying zone of the vane extruder at any moment. Because of the rotor eccentricity to the stator, a conveying mathematical model between the thickness of the material differential laminate and the rotor angle is established. The nonlinear function E(β) andG(β), related to the thickness, density and compactness of materials are obtained through experiment, and the radial force of inner surface of the stator acted on the differential laminate is calculated by the Hooke's law. Based on the torque balance of the material laminate, the force is calculated by integration in the chamber. The finite element analysis of the mathematic model are applied to verify the validity of the differential shear-compression theory, which is also practical to metal material rolling, high pressure double roll crush and other processes with converging geometry.
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Kaczor, Daniel, Krzysztof Bajer, Grzegorz Domek, Piotr Madajski, Aneta Raszkowska-Kaczor, and Paweł Szroeder. "Influence of Extruder Plasticizing Systems on the Selected Properties of PLA/Graphite Composite." Acta Mechanica et Automatica 16, no. 4 (October 14, 2022): 316–24. http://dx.doi.org/10.2478/ama-2022-0038.
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Abstract Twin-screw extrusion is a crucial method for the direct inserting of carbon micro- and nanomaterials into a polymer matrix using a dry procedure. The study aimed to determine the influence of the parameters of the twin-screw extruder plasticizing system on the dispersion homogeneity and distribution of graphite filler in the polylactide polymer matrix and overall quality of the composite. As a filler, a graphite micropowder with a 5 μm lateral size of platelets was used at concentration of 1 wt.%. Three configurations of screws with different mixing intensity and various types segments were considered in the extrusion experiments. Morphology and chemical structure of the obtained composites were examined using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy – attenuated total reflectance (FTIR-ATR) and Raman spectroscopy. Differential scanning calorimetry (DSC) and melting flow rate measurements (MFR) were used to asses thermal and rheological properties of the composites. Samples of the polylactide/graphite composites were also subjected to mechanical tests. The results show that the selection of the mechanical parameters of twin-screw extruder plasticizing system plays a key role in the preparation of the homogeneous PLA/graphite composites. Incorrect selection of the screw geometry results in poor mixing quality and a significant deterioration of the mechanical and thermal properties of the composites. Optimised mixing and extrusion parameters can be the starting point for the design of efficient twin-screw extruder plasticizing system for fabrication of PLA composites with carbon nanotube and graphene fillers.
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Truong, Tat-Tai, Quang-Cherng Hsu, Van-Canh Tong, and Jinn-Jong Sheu. "A Design Approach of Porthole Die for Flow Balance in Extrusion of Complex Solid Aluminum Heatsink Profile with Large Variable Wall Thickness." Metals 10, no. 5 (April 25, 2020): 553. http://dx.doi.org/10.3390/met10050553.
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In this study, porthole die used for extrusion of a solid heatsink profile with wall thickness variation ratio up to 15.3 was designed using finite element (FE) simulations. To improve the flow balance in the die, a design approach was introduced to find the appropriate die structure, which includes the porthole and pocket geometry correction, the bearing length adjustment, and the port bridge structure modification. Using the proposed die, the predicted velocity relative difference (VRD) and the maximum velocity difference (ΔV) of extrudate were significantly lower than those of an initial die, which was preliminarily designed based on general design experiences. The required extrusion force and the residual stress in the product were also reduced significantly. Then, the effects of the port bridge structure and welding chamber height on the behavior of the metal flow in the die were investigated. To verify the proposed die design, experimental extrusions were conducted on a 930-ton extruder. The experiment results showed that the extruded product fulfilled the requirements for dimensional tolerances. The design approach presented in this paper can be useful for practical implementation of die design when extruding similar solid heatsink profiles with large wall thickness variation.
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Wan, Qia, Youjian Xu, and Can Lu. "A fundamental study of parameter adjustable additive manufacturing process based on FDM process." MATEC Web of Conferences 189 (2018): 05001. http://dx.doi.org/10.1051/matecconf/201818905001.
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In Fused deposition modeling (FDM) process, there has been a confliction between high productivity and high quality of products. The product resolution is proportional to the flow rate of heated material extrusion, which directly affects the build time. To reduce the build time with acceptable resolution, the idea of parameter adjustable printing process has been introduced. The controllable extruder was modified and two types of diameter changeable nozzle have been designed. This work realizes different resolution building based on the part geometry during FDM process, which can efficiently assure the quality of products and improve the productivity at the same time.
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Rożeń, A., R. A. Bakker, and J. Bałdyga. "Effect of Operating Parameters and Screw Geometry on Micromixing in a Co-Rotating Twin-Screw Extruder." Chemical Engineering Research and Design 79, no. 8 (November 2001): 938–42. http://dx.doi.org/10.1205/02638760152721163.
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Bernardo, Felipe, José A. Covas, and Sebastião V. Canevarolo. "On-Line Optical Monitoring of the Mixing Performance in Co-Rotating Twin-Screw Extruders." Polymers 14, no. 6 (March 14, 2022): 1152. http://dx.doi.org/10.3390/polym14061152.
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The use of real-time techniques to evaluate the global mixing performance of co-rotating twin-screw extruders is well consolidated, but much less is reported on the specific contribution of individual screw zones. This work uses on-line flow turbidity and birefringence to ascertain the mixing performance of kneading blocks with different geometries. For this purpose, one of the barrel segments of the extruder was modified in order to incorporate four sampling devices and slit dies containing optical windows were attached to them. The experiments consisted in reaching steady extrusion and then adding a small amount of tracer. Upon opening each sampling device, material was laterally detoured from the local screw channel, and its turbidity and birefringence were measured by the optical detector. Residence time distribution curves (RTD) were obtained at various axial positions along three different kneading blocks and under a range of screw speeds. It is hypothesized that K, a parameter related to the area under each RTD curve, is a good indicator of dispersive mixing, whereas variance can be used to assess distributive mixing. The experimental data confirmed that these mixing indices are sensitive to changes in processing conditions, and that they translate the expected behavior of each kneading block geometry.
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Golman, Boris, Piotr Skrzypacz, and Wittaya Julklang. "Modeling and Numerical Study of Ceramic Paste Extrusion." MATEC Web of Conferences 333 (2021): 02011. http://dx.doi.org/10.1051/matecconf/202133302011.
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The extrusion processes of ceramic pastes, including 3D printing, are used for the production of high-value products. Ceramic paste extrusion is a complex process which depends on the paste rheological properties, die and extruder geometries, and operational parameters. Modeling and quantitative analysis of paste molding are important to design proper extrusion process for the production of high-value extrudates of desired strength, shape, and morphology. In this paper, the mathematical model of ram extrusion of ceramic materials is established, and the paste continuity and momentum equations for non-Newtonian fluid based on the modified Herschel-Bulkley viscous model were solved numerically. The effects of die geometry and paste feed rate on the distributions of paste velocity and pressure in the extruder and die were investigated numerically. As a result, the steeper radial profile of longitudinal velocity and higher value of longitudinal velocity were obtained in the narrow die. The pressure significantly increases in the die at a high feed rate, and the pressure profile is almost flat in the barrel. The rate of increase of the maximum pressure decreases with an increase of paste feed rate. The pressure steeply increases in the die of small diameter. The maximum pressure linearly increases with the ratio of die length to diameter.
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Golman, Boris, Piotr Skrzypacz, and Wittaya Julklang. "Modeling and Numerical Study of Ceramic Paste Extrusion." MATEC Web of Conferences 333 (2021): 02011. http://dx.doi.org/10.1051/matecconf/202133302011.
Full textAbstract:
The extrusion processes of ceramic pastes, including 3D printing, are used for the production of high-value products. Ceramic paste extrusion is a complex process which depends on the paste rheological properties, die and extruder geometries, and operational parameters. Modeling and quantitative analysis of paste molding are important to design proper extrusion process for the production of high-value extrudates of desired strength, shape, and morphology. In this paper, the mathematical model of ram extrusion of ceramic materials is established, and the paste continuity and momentum equations for non-Newtonian fluid based on the modified Herschel-Bulkley viscous model were solved numerically. The effects of die geometry and paste feed rate on the distributions of paste velocity and pressure in the extruder and die were investigated numerically. As a result, the steeper radial profile of longitudinal velocity and higher value of longitudinal velocity were obtained in the narrow die. The pressure significantly increases in the die at a high feed rate, and the pressure profile is almost flat in the barrel. The rate of increase of the maximum pressure decreases with an increase of paste feed rate. The pressure steeply increases in the die of small diameter. The maximum pressure linearly increases with the ratio of die length to diameter.
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Osipenko, M. A., and Y. I. Nyashin. "Model of leakages through radial clearences in a single screw extruder with linearly changing geometry of screw." Computational Continuum Mechanics 5, no. 4 (2012): 461–68. http://dx.doi.org/10.7242/1999-6691/2012.5.4.54.
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Sombatsompop, N., and M. Panaploy. "Die geometry effects on the temperature profile measurements of flowing PP melt in a twin-screw extruder." Polymer Testing 21, no. 1 (2002): 17–25. http://dx.doi.org/10.1016/s0142-9418(01)00039-3.
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Shalenko, Vadym, Boris Korniychuk, and Andriі Masluyk. "Z-axis limit switch 3D printer." Gіrnichі, budіvelnі, dorozhnі ta melіorativnі mashini, no. 96 (December 31, 2020): 22–27. http://dx.doi.org/10.32347/gbdmm2020.96.0301.
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Not much time has passed since the appearance of the first 3D printer. Today there are many different printers. They differ in various 3D printing technologies, namely: Stereolithography – SL, Selective Laser Sintering, Fused Deposition Modeling – FDM, Laminated Object Manufacturing – LOM, Polyjet and Ployjet Matrix.
In recent years, the spread of 3D printing technology has become and continues to be used more and more today. Of course, in the future we will see a large-scale spread of additive methods, but the practical application of 3D printing today is available to everyone. Melting deposition modeling technologies have become widespread and available.
The authors in this article consider possible options for upgrading the mounting of the end sensor of the Z Axis and automating the process of calibration of the zero gap of the extruder nozzle relative to the working surface of the printer. This calibration is important. This affects the accuracy and printing process of the future plastic model.
During the operation of the 3D printer, it is often necessary to service the extruder, which forces the process of calibrating the zero gap of the printer nozzle. Optimally correct selected nozzle clearance affects the accuracy, geometry of the model and printing as a whole. It also allows you to get rid of peeling off the model from the desktop surface and the destruction of the model during printing.
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Lucchetta, Giovanni, and Serafina Chirico. "Acetaldehyde Generation in Processing PET by Means of Hot Runner Systems." Key Engineering Materials 611-612 (May 2014): 922–27. http://dx.doi.org/10.4028/www.scientific.net/kem.611-612.922.
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Polyethylene terephthalate (PET) is a polyester widely used as packaging material in drink-bottling application. PET is rather sensitive to heat and oxidation and during processing it may undergo degradation reaction with generation of acetaldehyde. In this work the generation of acetaldehyde in a hot runner system has been measured. A special test apparatus was developed to separate the contributions due to the action of the extruder screw from those due to the melt residence at high temperature. Results showed that the acetaldehyde content non-linearly increases with temperature and residence time. A model has been proposed to provide for the generation of acetaldehyde as a function of temperature and residence time regardless of the geometry and other specific conditions of the process.
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Diaz-Perete, Daniel, Jorge Manuel Mercado-Colmenero, Jose Manuel Valderrama-Zafra, and Cristina Martin-Doñate. "New Procedure for BIM Characterization of Architectural Models Manufactured Using Fused Deposition Modeling and Plastic Materials in 4.0 Advanced Construction Environments." Polymers 12, no. 7 (July 4, 2020): 1498. http://dx.doi.org/10.3390/polym12071498.
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This paper presents a new procedure for the building information modeling (BIM) characterization of structural topologies manufactured with plastic materials and fused deposition modeling (FDM) additive technology. The procedure presented here transforms the architectural geometry into an expanded three-dimensional model, capable of directly linking the topology of the plastic structure with the technological, functional and economic requirements for working in advanced construction 4.0 environments. The model incorporates a new algorithm whose objective is to recognize the topological surface of the plastic structural part obtaining in a fully automated way the FDM manufacturing time as well as the manufacturing cost. The new algorithm starts from the voxelized geometrical surface of the architectural model, calculating the manufacturing time from the full geometric path traveled by the extruder in a voxel, the extruder’s speed, the print pattern and the layer height. In this way it is possible to obtain a complete digital model capable of managing and analyzing the plastic architectural object in an advanced BIM 4.0 environment. The model presented in this paper was applied to two architectural structures designed for a real urban environment. The final structural geometries have been obtained through topological processes in order to reduce the raw plastic manufacturing material and to improve the plastic structure strength. The architectural elements have been validated structurally by the means of numerical simulations, following the scenario of loads and boundary conditions required for the real project. The displacement maps point to a maximum value of 0.5 mm according to the project requirements. The Von Mises stress fields indicate maximum values of 0.423 and 0.650 MPa, not exceeding in any case the tensile yield strength of the thermoplastic material.
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Tesfaye Kebede, Ali, Esakki Balasubramanian, AS Praveen, Lade Rohit, and Kumar Arvind. "Preliminary investigations on extrusion of high viscosity slurry using direct writing technique." International Journal for Simulation and Multidisciplinary Design Optimization 11 (2020): 15. http://dx.doi.org/10.1051/smdo/2020012.
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Traditionally solid propellants are manufactured using casting and molding techniques. The effective burning rate of solid propellants is strongly depended on its cross section and geometry. The preparation of mold and mandrel for the manufacturability of various geometric profiles are tedious, time consuming, increases the cost and more human efforts are needed. In order to mitigate these issues, a disruptive technology called additive manufacturing (AM) is in the verge of development. Although the method is effective, additional study must be conducted to improve the flow characteristics of slurries for the high solid loading and there is a huge necessity to reduce the prolonged curing time. The present study focuses on preliminary investigations of extrusion of high viscosity slurry using a pneumatically driven extrusion system. The slurry was prepared with a 80 wt.% solid loading of NaCl having particle sizes of 45 µm and 150 µm, 15.6 wt.% HTPB, 2.2 wt.% TDI, 2.2 wt.% DOA and 0.03 wt.% of ferric acrylacetonate. The slurry was extruded with an aid of pneumatically controlled extruder and each layer was formed. Formed by extruding the slurry using 1.65 mm internal diameter nozzle. Infrared (IR) heater was utilized to transfer the radiational energy for partial curing of each layer and thereby adhesion of other layer was guaranteed. Simulation is performed to determine the temperature distribution using ANSYS platform for comparing the curing temperature of the printed part top surface. Preliminary experiments confirm that extrusion of slurry and heating of each layer can be effectively achieved with the proposed 3D printing technique. Three tensile specimens were produced in accordance with ASTMD 412-C and their corresponding mechanical properties are evaluated. The printed parts have the tensile strength of 0.7 MPa, elongation of 4.85 % and modulus of elasticity of 18.5 MPa which are comparable with the properties of conventional casted part.
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Nair, Sooraj A. O., Subhashree Panda, Manu Santhanam, Gaurav Sant, and Narayanan Neithalath. "A critical examination of the influence of material characteristics and extruder geometry on 3D printing of cementitious binders." Cement and Concrete Composites 112 (September 2020): 103671. http://dx.doi.org/10.1016/j.cemconcomp.2020.103671.
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Kowalski, Ryan J., Jacob P. Hause, Helen Joyner (Melito), and Girish M. Ganjyal. "Waxy flour degradation – Impact of screw geometry and specific mechanical energy in a co-rotating twin screw extruder." Food Chemistry 239 (January 2018): 688–96. http://dx.doi.org/10.1016/j.foodchem.2017.06.120.
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Robinson, Martin, and Paul W. Cleary. "Effect of geometry and fill level on the transport and mixing behaviour of a co-rotating twin screw extruder." Computational Particle Mechanics 6, no. 2 (October 22, 2018): 227–47. http://dx.doi.org/10.1007/s40571-018-0210-y.
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Dovzhik, M. T. "Ways of increase of efficiency of process of the vibroextrusion of fibrous concrete." Кераміка: наука і життя, no. 2(43) (July 7, 2019): 18–22. http://dx.doi.org/10.26909/csl.2.2019.3.
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The process of mixing the components of the mixture is an important factor affecting the physical and mechanical properties and appearance of the final product. The proposed designs of vibroexcluders for mixing fibrous concrete and the formation of flat products provided analytical formulas for calculating the process of vibration extrusion.
The quantitative criterion of laminar convective mixing, which occurs when vibroexclusion, is the degree of increase in the surface area of the interface between the components, which in turn depends on the total deformation and initial orientation of the surface.
The constructions of vibroextruders are provided for the mixing of a fibrous concrete and forming flat products, and analytical formulas are given for the calculation of the vibroextrusion process.
The construction of a cascade vibrating extruder for the proposed mixing can be applied to a wide range of compositions of fibro concrete mixes, and a specially designed vibratory extruder for forming can significantly improve the longitudinal orientation of dispersed fittings in flat products.
The degree of longitudinal orientation of the fiber in the process of vibroexclusion of fiber concrete can be regulated by the geometry and size of the channels of the vibroexcutter bunker, as well as by the application of special guiding partitions.
Practically the degree of mixing is characterized by the speed of vibration exclusion. Due to the fact that the vibroextrusion mixing does not occur the destruction of fiber reinforcement, as a result of the successive passage of the mixture through several channels, the moment when the vibration excursion velocity stabilizes.
The given analytical dependencies give the possibility of quantitative description of differences in the deformation of the mixture and the final orientation of fibers in the products for the proposed apparatus. The degree of longitudinal orientation fibers need to be set separately for different products, depending on their purpose, and change the degree of orientation is carried out by changing the geometry of the vane bunker vibroextruder.
The results of the work are supposed to be used in the design of a new vibration excretory equipment for mixing fibrous concrete mixtures and the formation of dispersed reinforced products.
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Slapnik, Janez, Gregor Kraft, Thomas Wilhelm, Marcel Hribernik, Iztok Švab, Thomas Lucyshyn, and Gerald Pinter. "Influence of Viscose Fibre Geometry on the Structure–Property Relationships of High-Density Polyethylene Composites." Polymers 14, no. 20 (October 18, 2022): 4389. http://dx.doi.org/10.3390/polym14204389.
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This study investigated the influence of viscose fibre (VF) geometry on the microstructures and resulting properties of high-density polyethylene (HDPE) composites. Seven types of viscose fibres varying in cross-section shape, linear density, and length were pelletised, compounded into HDPE with a twin-screw extruder, and injection moulded. The microstructures of the composites were characterised by investigating their cross-sections and by extracting the fibres and measuring their lengths using optical microscopy (OM). The mechanical and thermal properties of the composites were characterised using differential scanning calorimetry (DSC), tensile tests, Charpy impact tests, and dynamic mechanical analysis (DMA). The composites prepared using cylindrical fibres with a linear density of 1.7 dtex exhibited the best fibre dispersion, highest orientation, and lowest fibre–fibre contact area. The decrease in the linear density of the cylindrical fibres resulted in increasingly worse dispersion and orientation, while composites containing non-cylindrical fibres exhibited a comparably larger fibre–fibre contact area. The initial fibre length of about 3 to 10 mm decreased to the mean values of 0.29 mm to 0.41 mm during processing, depending on the initial geometry. In general, cylindrical fibres exhibited a superior reinforcing effect in comparison to non-cylindrical fibres. The composites containing cylindrical fibres with a linear density of 1.7 dtex and a length of 5 mm exhibited the best reinforcing effect with an increase in tensile modulus and strength of 323% and 141%, respectively.
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Sengupta, Rajarshi, Mukul D. Tikekar, James V. Raj, Kris T. Delaney, Michael C. Villet, and Glenn H. Fredrickson. "Phase-field simulations of morphology development in reactive polymer blending." Journal of Rheology 67, no. 1 (January 2023): 1–14. http://dx.doi.org/10.1122/8.0000523.
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Reactive blending is an efficient method for synthesizing polymer blends. Industrially, this process is carried out in extruders, where the reacting polymers and the generated copolymer are subjected to high shear stresses. The dynamics of the process, and the resulting morphology is dictated by a coupling of the hydrodynamic forces in the extruder, the thermodynamic interactions between species, and the reaction kinetics on a complex interfacial manifold. We use phase-field simulations to quantify the evolution of the reactive blending process under an external shear flow. Specifically, we consider a model system of two homopolymers of equal length, which react via an end-coupling reaction to form a diblock copolymer of double the length. We compare the morphology development in two different initial geometries of the homopolymers—a cylindrical thread and a drop of one homopolymer in a matrix of the second. We investigate the effect of flow strength, measured by the shear rate, and reaction kinetics, quantified by a Damkohler number, on the progress of the reaction and morphology development. Cylindrical threads are susceptible to breakup via the Rayleigh capillary instability. We demonstrate that this instability can be suppressed by imposing shear along the direction of the thread and increasing the extent of the reaction. The reaction rate in this geometry is unaffected by shear imposed along the cylinder axis. Drops deform significantly under an imposed flow, eventually stretching to long cylindrical threads for sufficient shear rates. In the case of drops, shear stresses enhance the reaction rate by deforming the drop, enabling more homopolymers to come in contact at the expanded interface. We show that shear stresses significantly impact the morphology development and reaction dynamics in reactive polymer blending.
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Pisanu, Luciano, Leonardo Costa Santiago, Josiane Dantas Viana Barbosa, Valter Estevão Beal, and Marcio Luis Ferreira Nascimento. "Effect of the Process Parameters on the Adhesive Strength of Dissimilar Polymers Obtained by Multicomponent Injection Molding." Polymers 13, no. 7 (March 26, 2021): 1039. http://dx.doi.org/10.3390/polym13071039.
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The growing demand in the consumer market for products with sustainable technologies has motivated new applications using overmolded natural fiber composites. Therefore, studies have been conducted mainly to understand the adhesive properties of overmolded parts. In the present study, a polypropylene (PP) composite with 30% coconut fibers without additives was developed with the aid of a corotating twin screw extruder. Subsequently, a multicomponent injection mold was developed based on the geometry of the ISO 527 type I specimen, in which samples overmolded with PP and PP–coconut-fiber composite, with the overlap in the central area, were obtained to evaluate the adhesive strength of dissimilar materials. The objective of this study was to evaluate the bond between PP and PP–coconut-fiber composite under different processing conditions using an adhesive strength testing device to perform a pure shear analysis. The experimental conditions followed a statistical design considering four factors in two levels and a significance level of 5%. The results indicated that adhesive strength increased significantly as the overlap area increased. It was observed that temperature and injection flow rate were the factors that most contributed to strengthening the bonds of dissimilar materials.
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Liu, Yanchang, Yiren Pan, Xuehua Hu, and Fang Yu. "Squeezing Mechanical Analysis and Model Establishment of the Viscoelastic Rubber-Strip-Feeding Process of the Cold-Feed Rubber Extruder." Polymers 14, no. 17 (August 31, 2022): 3602. http://dx.doi.org/10.3390/polym14173602.
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In the process of rubber extrusion, the feed structure directly affects the extrusion quality, extrusion uniformity, screw lateral force, and feed power consumption. Until now, the feed structure was mainly based on empirical designs, and there was no theoretical model for the optimal design of a feed structure. This paper focused on the squeezing mechanical analysis and model establishment of the feeding process in which viscoelastic rubber strips are passed through feed-wedge clearance in cold-feed extruders. The screw flight rotation squeezing process was simplified into a disc rotation squeezing process; the instantaneous squeezing velocity in the disc rotation squeezing model was derived according to feed wedge clearance geometry and the disc rotating speed. By transforming rotation squeezing into differential slab squeezing, mathematical expressions of the velocity distribution, pressure distribution, total squeezing force, and power consumption in the feeding process were derived in a rectangular coordinate system under isothermal and quasi-steady assumptions and certain boundary conditions by using balance equations and a Newtonian viscous constitutive relation. Theoretical calculations and experimental values showed the same trend. Through comparison, it was found that the power consumption (P3) caused by sliding friction is about 200–900 W according to theoretical calculations, while the experimental test results show it to be about 300–700 W. Additionally, the difference between theoretical pressure value and the experimental pressure value can be controlled within 5–15%. This could reflect the main factors that affect the feeding process, so could be used for analyses of actual feeding problems, and to contribute to rough quantitative descriptions of the feeding process, finite element simulation, and the optimization of the feeding structure.
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Minguella, J., P. R. Challa, M. A. De Los Santos, J. Lobo, P. Morey, and J. M. Font. "Re-design of a component of a lower-limb robotic exoskeleton for integrating sensing capacity and enhancing multi-material direct additive manufacturing." IOP Conference Series: Materials Science and Engineering 1193, no. 1 (October 1, 2021): 012097. http://dx.doi.org/10.1088/1757-899x/1193/1/012097.
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Abstract The quest for the materialisation of advanced products is expanding the need for intelligent components and devices. One of the fields of application for such products is the medical technology industry, in which many value-added products could benefit from extending its embedded functionalities. To this regard, the obtention of such products via Additive Manufacturing Technologies would be very beneficial, providing that the design requirements could be met in a seamless and direct manner. In this context, the present article develops and analyses three design iterations of a component of a lower-limb robotic exoskeleton for integrating sensing capacity on it via multi-material direct additive manufacturing. In subsequent steps, the component geometry is optimised for additive direct manufacturing, and different functionalities are incorporated (padding for comfort and circuitry for sensing). For each iteration, the design is validated by means of finite element analysis and the main manufacturing parameters are assessed to compare the different times and costs yield. The third redesign incorporates three different materials (ABS, TPU and PE+Cu), but still it is possible to be 3D printed with a two extruder-head FDM 3D printer. The design and manufacturing results obtained could be implemented in further biomedical products or other parts requiring advanced functionalities.
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Shayuti, Muhammad Shafiq Mat, Rahida Wati Sharudin, Tengku Amran Tengku Mohd, Putri Nadzrul Faizura Megat Khamaruddin, Mohamad Zaki Abdullah, and Puteri Sri Melor Megat Yusoff. "Thermal Conductivity and Crystallography of Polypropylene/Polycarbonate/ Polypropylene-Graft-Maleic Anhydride Polymer Blend." Materials Science Forum 995 (June 2020): 56–62. http://dx.doi.org/10.4028/www.scientific.net/msf.995.56.
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The effect of blending polycarbonate (PC) into polypropylene (PP) matrix polymer on thermal conductivity and crystal structure was studied. The blends consisted of 5% to 35% of PC with 5% compatibilizer (polypropylene-graft-maleic anhydride or PP-g-MA), were compounded using twin-screw extruder and shaped into standard tests samples by compression molding. The thermal conductivity values for PP/PC/PP-g-MA blends were ranging from 0.22 – 0.24 W/m.K. When compared to Hanshin – Shtrikman model, the highest difference in the thermal conductivity values was 28.2% shown in 90/5/5 composition. The deviation was due to the exclusion of factors such as PC particulates’ geometry, size, and dispersion in PP matrix. X-ray Diffraction (XRD) test revealed the blends’ structures comprised of medium-range order domains, referring to imperfect crystals with nanoparticles. The locations of peaks in the XRD spectrum also suggest that the pure PP’s monoclinic alpha crystal appeared in all PP/PC/PP-g-MA blends and there was no other crystal obtained in the blends. From the result, the discovered traits of crystal structure displayed influence on the thermal conductivity of the blends. At the same time, reactive compatibilization was suspected to take place at the interface of PP and PC phases when PP-g-MA was introduced.
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Costanza, Girolamo, Angelo Del Ferraro, and Maria Elisa Tata. "Experimental Set-Up of the Production Process and Mechanical Characterization of Metal Foams Manufactured by Lost-PLA Technique with Different Cell Morphology." Metals 12, no. 8 (August 20, 2022): 1385. http://dx.doi.org/10.3390/met12081385.
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A flexible and versatile method for manufacturing open-cell metal foams, called lost-PLA, is presented in this work. With a double extruder 3D printer (FDM, Ultimaker S3, Utrecht, The Netherlands), it is possible to make polymer-based samples of the lost model. Through CAD modeling, different geometries were replicated so as to get black PLA samples. This method combines the advantages of rapid prototyping with the possibility of manufacturing Al-alloy specimens with low time to market. The production process is articulated in many steps: PLA foams are inserted into an ultra-resistant plaster mix, after which the polymer is thermally degraded. The next step consists of the gravity casting of the EN-6082 alloy in the plaster form, obtaining metal foams that are interesting from a technological point of view as well as with respect to their mechanical properties. These foam prototypes can find application in the automotive, civil and aeronautical fields due to their high surface/weight ratio, making them optimal for heat exchange and for the ability to absorb energy during compression. The main aspects on which we focus are the set-up of the process parameters and the characterization of the mechanical properties of the manufactured samples. The main production steps are examined at first. After that, the results obtained for mechanical performance during static compression tests with different geometry porosities are compared and discussed. The foam with truncated octahedron cells was found to show the highest absorbed energy/relative density ratio.
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Little, Helen A., Nagendra G. Tanikella, Matthew J. Reich, Matthew J. Fiedler, Samantha L. Snabes, and Joshua M. Pearce. "Towards Distributed Recycling with Additive Manufacturing of PET Flake Feedstocks." Materials 13, no. 19 (September 25, 2020): 4273. http://dx.doi.org/10.3390/ma13194273.
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This study explores the potential to reach a circular economy for post-consumer Recycled Polyethylene Terephthalate (rPET) packaging and bottles by using it as a Distributed Recycling for Additive Manufacturing (DRAM) feedstock. Specifically, for the first time, rPET water bottle flake is processed using only an open source toolchain with Fused Particle Fabrication (FPF) or Fused Granular Fabrication (FGF) processing rather than first converting it to filament. In this study, first the impact of granulation, sifting, and heating (and their sequential combination) is quantified on the shape and size distribution of the rPET flakes. Then 3D printing tests were performed on the rPET flake with two different feed systems: an external feeder and feed tube augmented with a motorized auger screw, and an extruder-mounted hopper that enables direct 3D printing. Two Gigabot X machines were used, each with the different feed systems, and one without and the latter with extended part cooling. 3D print settings were optimized based on thermal characterization, and both systems were shown to 3D print rPET directly from shredded water bottles. Mechanical testing showed the importance of isolating rPET from moisture and that geometry was important for uniform extrusion. The mechanical strength of 3D-printed parts with FPF and inconsistent flow is lower than optimized fused filament, but adequate for a wide range of applications. Future work is needed to improve consistency and enable water bottles to be used as a widespread DRAM feedstock.
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Singh Boparai, Kamaljit, Rupinder Singh, and Harwinder Singh. "Experimental investigations for development of Nylon6-Al-Al2O3 alternative FDM filament." Rapid Prototyping Journal 22, no. 2 (March 21, 2016): 217–24. http://dx.doi.org/10.1108/rpj-04-2014-0052.
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Purpose The purpose of this paper is to fabricate Nylon6-Al-Al2O3-based alternative fused deposition modeling process (FDM) feedstock filament in place of commercial acrylonitrile butadiene styrene (ABS) filament (having required rheological and mechanical properties) for rapid manufacturing (RM) and rapid tooling (RT) applications. The detailed steps for fabrication of alternative FDM feedstock filament (as per field application) with relatively low manufacturing cost and tailor-made properties have been highlighted. Design/methodology/approach The rheological and mechanical suitability of nylon6-Al-Al2O3 feedstock filament has been investigated experimentally. The approach is to predict and incorporate essential properties such as flow rate, flexibility, stiffness and mechanical strength at processing conditions and compared with commercial ABS material. The proportions of various constituents have been varied to modify and improve rheological behavior and mechanical properties of alternative FDM feedstock filament. Findings The alternative material of feed stock filament was successfully developed and loaded in commercial FDM setup without changing any hardware and software. The result of study suggests that the newly developed composite material filament has relatively poor mechanical properties but have highly thermal stability and wear resistant as compared to ABS filament and hence can be used for tailor-made applications. Research limitations/implications In this work, no additive was added for improving the bond formation of metal and polymeric materials. The newly developed filament was prepared on single screw extruder. For more uniform mixing of metal and polymeric materials, further studies may be conducted on twin screw extruder. Also, for the present research work, the testing of newly developed filament has been limited up to mechanical testing, which may be extended to chemical and thermal analysis to understand thermal stability and degradation mechanism of newly developed composite material. Practical implications The proportion of filler material (Al-Al2O3) in Nylon6 matrix was set as a constraint, which was adjusted based upon melt flow index of original equipment manufacturer developed material (ABS), and temperature conditions were available at FDM nozzle (so that hardware and software system of commercial FDM setup need not to be altered). Originality/value The present approach outlined selection, processing, fabrication and testing procedure for alternate feedstock filament, which fulfills the necessary requirements of FDM process and has been customized for RT and RM applications. This work highlights mechanical strength evaluation of feedstock filament (which is necessary before the loading of material in FDM system). The potential applications of this investigation include RM of functional parts, tailor-made grinding tools for dentists and RT of metal matrix composite having complex geometry.
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Azhikannickal, Elizabeth, and Aaron Uhrin. "Dimensional Stability of 3D Printed Parts: Effects of Process Parameters." Ohio Journal of Science 119, no. 2 (July 12, 2019): 9. http://dx.doi.org/10.18061/ojs.v119i2.6593.
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The three-dimensional (3D) printing manufacturing process begins with the creation of a 3D model—using computer aided design (CAD) software—of the part to be printed. Using a type of 3D printing known as fused deposition modeling (FDM®), the 3D printer extrudes molten plastic to scan lines to create individual layers (i.e., the infill): one on top of the other. (Note that "scan" in this context refers to the movement of the extruder head, along an x,y coordinate path, while depositing molten plastic.) This process is repeated until the overall geometry, specified by the 3D model, is built. This process is attractive for producing proof of concept or prototype parts in various fields including automotive, aerospace, and medical. However, FDM subjects the material to rapid heating and cooling; therefore, some degree of undesirable warpage of the part occurs post fabrication. The primary objective of this study was to determine the effect of 4 process parameters (i.e., infill shape, infill density, number of perimeters created per layer, and layer height) on the total dimensional error of a representative 3D-printed part. This part (the "simple part"), used in Trials 1 through 3 of this study, was a square acrylonitrile butadiene styrene (ABS) plate having a nominal measurement of 50 mm × 50 mm × 5 mm thick. A residual error (the difference between the measured post-printing dimension and the theoretical CAD file dimension) was calculated along each given direction and for each test print. Finally, a root mean square (RMS) error (i.e., the square root of the average of the squared residual errors along the length, width, and thickness directions) was calculated for each printed part. Three repeat test prints were carried out for each parameter. The number of perimeters played a key role in the dimensional stability of the part. As the number of perimeters increased up to 5, the RMS error decreased. Beyond 5 perimeters, however, the RMS error increased due to excessive warpage/curvature at the corners of the part. Ultimately, when examined individually, a grid infill shape at 100% density, a 0.4 mm layer height, and 5 perimeters each produced the lowest warpage. In combination, these same 4 parameters also produced the lowest RMS error (based on dimensional analysis of 3 test prints) when used to print a more complicated part (the "stacked part") in Trial 4.
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Liu, Yong Feng, Ai Hua Zhu, Jian Wei Yang, and Hong Sen Tian. "Study on Product Virtual Design for the Diesel Engine Combustion System." Advanced Materials Research 479-481 (February 2012): 1691–94. http://dx.doi.org/10.4028/www.scientific.net/amr.479-481.1691.
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To carry out product virtual design for diesel engine combustion system, the top-down method is used. The diesel engine combustion system is designed and each part is modeled in Pro/E. Pro/E is a solid modeler and this offers considerable advantage for solid model creation. Normally, the geometry is first sketched in 2-D and then extruded in the third direction to generate a 3-D model. In Pro/E, it is important to first create the base geometry. The base geometry is that captures the design intent of the part to be modeled. This base geometry can be created using either the EXTRUDE or the REVOLVE options. Once this base geometry has been created, additional features like holes, rounds, chamfers, fillets, ribs, etc can be added in the finishing stages of the part creation. The center of the bowl does not coincide with the center of the cylinder due to the presence of valve pockets. The obvious advantage of this configuration is that is gives the true geometry of the piston and the connecting rod ports can be accommodated when the piston is at the top dead center.