Academic literature on the topic 'Extruder geometry'
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Journal articles on the topic "Extruder geometry"
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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.
Full textAbstract:
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.
Full textDissertations / Theses on the topic "Extruder geometry"
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Elsey, Justin Rae. "Dynamic Modelling, Measurement and Control of Co-rotating Twin-Screw Extruders." University of Sydney. Department of Chemical Engineering, 2003. http://hdl.handle.net/2123/687.
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Co-rotating twin-screw extruders are unique and versatile machines that are used widely in the plastics and food processing industries. Due to the large number of operating variables and design parameters available for manipulation and the complex interactions between them, it cannot be claimed that these extruders are currently being optimally utilised. The most significant improvement to the field of twin-screw extrusion would be through the provision of a generally applicable dynamic process model that is both computationally inexpensive and accurate. This would enable product design, process optimisation and process controller design to be performed cheaply and more thoroughly on a computer than can currently be achieved through experimental trials. This thesis is divided into three parts: dynamic modelling, measurement and control. The first part outlines the development of a dynamic model of the extrusion process which satisfies the above mentioned criteria. The dynamic model predicts quasi-3D spatial profiles of the degree of fill, pressure, temperature, specific mechanical energy input and concentrations of inert and reacting species in the extruder. The individual material transport models which constitute the dynamic model are examined closely for their accuracy and computational efficiency by comparing candidate models amongst themselves and against full 3D finite volume flow models. Several new modelling approaches are proposed in the course of this investigation. The dynamic model achieves a high degree of simplicity and flexibility by assuming a slight compressibility in the process material, allowing the pressure to be calculated directly from the degree of over-fill in each model element using an equation of state. Comparison of the model predictions with dynamic temperature, pressure and residence time distribution data from an extrusion cooking process indicates a good predictive capability. The model can perform dynamic step-change calculations for typical screw configurations in approximately 30 seconds on a 600 MHz Pentium 3 personal computer. The second part of this thesis relates to the measurement of product quality attributes of extruded materials. A digital image processing technique for measuring the bubble size distribution in extruded foams from cross sectional images is presented. It is recognised that this is an important product quality attribute, though difficult to measure accurately with existing techniques. The present technique is demonstrated on several different products. A simulation study of the formation mechanism of polymer foams is also performed. The measurement of product quality attributes such as bulk density and hardness in a manner suitable for automatic control is also addressed. This is achieved through the development of an acoustic sensor for inferring product attributes using the sounds emanating from the product as it leaves the extruder. This method is found to have good prediction ability on unseen data. The third and final part of this thesis relates to the automatic control of product quality attributes using multivariable model predictive controllers based on both direct and indirect control strategies. In the given case study, indirect control strategies, which seek to regulate the product quality attributes through the control of secondary process indicators such as temperature and pressure, are found to cause greater deviations in product quality than taking no corrective control action at all. Conversely, direct control strategies are shown to give tight control over the product quality attributes, provided that appropriate product quality sensors or inferential estimation techniques are available.
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Elsey, Justin Rae. "Dynamic Modelling, Measurement and Control of Co-rotating Twin-Screw Extruders." Thesis, The University of Sydney, 2002. http://hdl.handle.net/2123/687.
Full textAbstract:
Co-rotating twin-screw extruders are unique and versatile machines that are used widely in the plastics and food processing industries. Due to the large number of operating variables and design parameters available for manipulation and the complex interactions between them, it cannot be claimed that these extruders are currently being optimally utilised. The most significant improvement to the field of twin-screw extrusion would be through the provision of a generally applicable dynamic process model that is both computationally inexpensive and accurate. This would enable product design, process optimisation and process controller design to be performed cheaply and more thoroughly on a computer than can currently be achieved through experimental trials. This thesis is divided into three parts: dynamic modelling, measurement and control. The first part outlines the development of a dynamic model of the extrusion process which satisfies the above mentioned criteria. The dynamic model predicts quasi-3D spatial profiles of the degree of fill, pressure, temperature, specific mechanical energy input and concentrations of inert and reacting species in the extruder. The individual material transport models which constitute the dynamic model are examined closely for their accuracy and computational efficiency by comparing candidate models amongst themselves and against full 3D finite volume flow models. Several new modelling approaches are proposed in the course of this investigation. The dynamic model achieves a high degree of simplicity and flexibility by assuming a slight compressibility in the process material, allowing the pressure to be calculated directly from the degree of over-fill in each model element using an equation of state. Comparison of the model predictions with dynamic temperature, pressure and residence time distribution data from an extrusion cooking process indicates a good predictive capability. The model can perform dynamic step-change calculations for typical screw configurations in approximately 30 seconds on a 600 MHz Pentium 3 personal computer. The second part of this thesis relates to the measurement of product quality attributes of extruded materials. A digital image processing technique for measuring the bubble size distribution in extruded foams from cross sectional images is presented. It is recognised that this is an important product quality attribute, though difficult to measure accurately with existing techniques. The present technique is demonstrated on several different products. A simulation study of the formation mechanism of polymer foams is also performed. The measurement of product quality attributes such as bulk density and hardness in a manner suitable for automatic control is also addressed. This is achieved through the development of an acoustic sensor for inferring product attributes using the sounds emanating from the product as it leaves the extruder. This method is found to have good prediction ability on unseen data. The third and final part of this thesis relates to the automatic control of product quality attributes using multivariable model predictive controllers based on both direct and indirect control strategies. In the given case study, indirect control strategies, which seek to regulate the product quality attributes through the control of secondary process indicators such as temperature and pressure, are found to cause greater deviations in product quality than taking no corrective control action at all. Conversely, direct control strategies are shown to give tight control over the product quality attributes, provided that appropriate product quality sensors or inferential estimation techniques are available.
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Vera-Sorroche, Javier. "Thermal homogeneity and energy efficiency in single screw extrusion of polymers : the use of in-process metrology to quantify the effects of process conditions, polymer rheology, screw geometry and extruder scale on melt temperature and specific energy consumption." Thesis, University of Bradford, 2014. http://hdl.handle.net/10454/13965.
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Polymer extrusion is an energy intensive process whereby the simultaneous action of viscous shear and thermal conduction are used to convert solid polymer to a melt which can be formed into a shape. To optimise efficiency, a homogeneous melt is required with minimum consumption of process energy. In this work, in-process monitoring techniques have been used to characterise the thermal dynamics of the single screw extrusion process with real-time quantification of energy consumption. Thermocouple grid sensors were used to measure radial melt temperatures across the melt flow at the entrance to the extruder die. Moreover, an infrared sensor flush mounted at the end of the extruder barrel was used to measure non-invasive melt temperature profiles across the width of the screw channel in the metering section of the extruder screw. Both techniques were found to provide useful information concerning the thermal dynamics of the extrusion process; in particular this application of infrared thermometry could prove useful for industrial extrusion process monitoring applications. Extruder screw geometry and extrusion variables should ideally be tailored to suit the properties of individual polymers but in practise this is rarely achieved due the lack of understanding. Here, LDPE, LLDPE, three grades of HDPE, PS, PP and PET were extruded using three geometries of extruder screws at several set temperatures and screw rotation speeds. Extrusion data showed that polymer rheology had a significant effect on the thermal efficiency on the extrusion process. In particular, melt viscosity was found to have a significant effect on specific energy consumption and thermal homogeneity of the melt. Extruder screw geometry, set extrusion temperature and screw rotation speed were also found to have a direct effect on energy consumption and melt consistency. Single flighted extruder screws exhibited poorer temperature homogeneity and larger fluctuations than a barrier flighted screw with a spiral mixer. These results highlighted the importance of careful selection of processing conditions and extruder screw geometry on melt homogeneity and process efficiency. Extruder scale was found to have a significant influence on thermal characteristics due to changes in surface area of the screw, barrel and heaters which consequently affect the effectiveness of the melting process and extrusion process energy demand. In this thesis, the thermal and energy characteristics of two single screw extruders were compared to examine the effect of extruder scale and processing conditions on measured melt temperature and energy consumption. Extrusion thermal dynamics were shown to be highly dependent upon extruder scale whilst specific energy consumption compared more favourably, enabling prediction of a process window from lab to industrial scale within which energy efficiency can be optimised. Overall, this detailed experimental study has helped to improve understanding of the single screw extrusion process, in terms of thermal stability and energy consumption. It is hoped that the findings will allow those working in this field to make more informed decisions regarding set conditions, screw geometry and extruder scale, in order to improve the efficiency of the extrusion process.
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Nagaraj, Aditi. "The effect of die geometry on extruded paste flow for continuous production of pharmaceutical tablets." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/68850.
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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, February 2011."February 2011." Vita. Cataloged from PDF version of thesis.
Includes bibliographical references (p. 33).
The design of an extruder-based continuous tablet forming process of a sample active pharmaceutical ingredient (API) and ethyl acetate requires a device to form and compress the tablets. The flow of the wet extrusion is driven by the pressure head generated by the torque of the screws; the minimum pressure head is dictated by the head loss across the exit die. Since the API powder blend and ethyl acetate solvent form a highly filled suspension paste, the liquid phase tends to flow at a different speed than the solid when the driving pressure changes. As such, the three die geometries, straight, curve, and elbow, resulted in average steady state liquid mass fraction of 0.179 ± 0.005, 0.249 + 0.01, and 0.200 ± 0.009 respectively, although the increases in mass fraction do not correspond to increases in pressure drop across the die. This experiment tests a particular tablet forming process, which involves using the pressure of the extruder to squeeze out the liquid content of the tablets during forming. The occurrence of liquid phase migration after this tabletting process is confirmed in each die tested. The extent of variation in liquid content shows a 30% increase for the straight die, a 50-200% increase for the curve die, and 50-150% increase for the elbow die. These results suggest that a tablet forming device should not use the pressure of the extruder, due to the complications of paste flow.
by Aditi Nagaraj.
S.B.
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Stasiek, Andrzej. "Badania procesu współbieżnego dwuślimakowego wytłaczania modyfikowanego polipropylenu przy zmiennej geometrii ślimaków." Rozprawa doktorska, Uniwersytet Technologiczno-Przyrodniczy w Bydgoszczy, 2015. http://dlibra.utp.edu.pl/Content/886.
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Celem pracy było badanie i opis wybranych cech konstrukcyjnych ślimaków wytłaczarki dwuślimakowej współbieżnej oraz parametrów technologicznych procesu na właściwości kompozytów PP/talk wytworzonych w tym procesie
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Chien-Nan, Chou, and 周建男. "Study on Rotor's Geometry Modeling of Twin Screw Extruder." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/79752587832652510935.
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碩士正修科技大學
機電工程研究所
94
Twin screw extruders have become, an important part of processing technology especially for polymer processing. They are widely used in chemical plants for reactive processing including both polymerization and grafting reactions. In chemical/polymerization plants, they are used for post-reactive processing steps including coagulation and devolatilization. Twin screw extruders are also used in post polymerization plant bulk polymer processing. This includes compounding of particulates, blending and reactive processing of polymers. There are also applications to thermoplastic final shaping operations, particularly for profile extrusion. In order to get best economic benefits and quickest time response, the advantages and shortages of existing methods for machining twin-screws are analyzed. In view of the production of co-rotating twin-screw is various and mostly in small batch, a new approach for forming cylinder helical surface with milling cutter is put forward. It presents the theoretical foundation for machining of twin-screw. Changing the diameters and fixing angles of milling cutter can meet the machining requirements of helical surface. This method has been applied in the process of manufacturing twin-screw in rubber and plastic mechanics, which simplifies the process route and shortens the prepare time in production and the same time saves the cost and improves technical and economic benefits. The mathematic model of co-rotating twin-screw machining with milling tool is built. According to this model the tool parameters and theoretical machining error are computed and analyzed. The technique and approach can effectively aid the designing and choosing of cylinder helical surface machining tools for co-rotating twin-screw. The process of co-rotating twin-screw machining is simulated based on the theory of machining with milling cutter, and the machining simulation theory and its key techniques are discussed. The mathematic model and computation are proved correct and feasible through cutting experiment.
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Deng, J., K. Li, E. Harkin-Jones, M. Price, N. Karnachi, Adrian L. Kelly, Javier Vera-Sorroche, Philip D. Coates, Elaine C. Brown, and M. R. Fei. "Energy monitoring and quality control of a single screw extruder." 2014. http://hdl.handle.net/10454/10619.
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YesPolymer extrusion, in which a polymer is melted and conveyed to a mould or die, forms the basis of most polymer processing techniques. Extruders frequently run at non-optimised conditions and can account for 15-20% of overall process energy losses. In times of increasing energy efficiency such losses are a major concern for the industry. Product quality, which depends on the homogeneity and stability of the melt flow which in turn depends on melt temperature and screw speed, is also an issue of concern of processors. Gear pumps can be used to improve the stability of the production line, but the cost is usually high. Likewise it is possible to introduce energy meters but they also add to the capital cost of the machine. Advanced control incorporating soft sensing capabilities offers opportunities to this industry to improve both quality and energy efficiency. Due to strong correlations between the critical variables, such as the melt temperature and melt pressure, traditional decentralized PID (Proportional-Integral-Derivative) control is incapable of handling such processes if stricter product specifications are imposed or the material is changed from one batch to another. In this paper, new real-time energy monitoring methods have been introduced without the need to install power meters or develop data-driven models. The effects of process settings on energy efficiency and melt quality are then studied based on developed monitoring methods. Process variables include barrel heating temperature, water cooling temperature, and screw speed. Finally, a fuzzy logic controller is developed for a single screw extruder to achieve high melt quality. The resultant performance of the developed controller has shown it to be a satisfactory alternative to the expensive gear pump. Energy efficiency of the extruder can further be achieved by optimising the temperature settings. Experimental results from open-loop control and fuzzy control on a Killion 25 mm single screw extruder are presented to confirm the efficacy of the proposed approach. (C) 2013 Elsevier Ltd. All rights reserved.
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Abeykoon, Chamil, P. J. Martin, Adrian L. Kelly, K. Li, Elaine C. Brown, and Philip D. Coates. "Investigation of the Temperature Homogeneity of Die Melt Flows in Polymer Extrusion." 2014. http://hdl.handle.net/10454/10566.
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NoPolymer extrusion is fundamental to the processing of polymeric materials and melt flow temperature homogeneity is a major factor which influences product quality. Undesirable thermal conditions can cause problems such as melt degradation, dimensional instability, weaknesses in mechanical/optical/geometrical properties, and so forth. It has been revealed that melt temperature varies with time and with radial position across the die. However, the majority of polymer processes use only single-point techniques whose thermal measurements are limited to the single point at which they are fixed. Therefore, it is impossible for such techniques to determine thermal homogeneity across the melt flow. In this work, an extensive investigation was carried out into melt flow thermal behavior of the output of a single extruder with different polymers and screw geometries over a wide range of processing conditions. Melt temperature profiles of the process output were observed using a thermocouple mesh placed in the flow and results confirmed that the melt flow thermal behavior is different at different radial positions. The uniformity of temperature across the melt flow deteriorated considerably with increase in screw rotational speed while it was also shown to be dependent on process settings, screw geometry, and material properties. Moreover, it appears that the effects of the material, machine, and process settings on the quantity and quality of the process output are heavily coupled with each other and this may cause the process to be difficult to predict and variable in nature. (C) 2013 Society of Plastics Engineers
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Kelly, Adrian L., Elaine C. Brown, and Philip D. Coates. "The effect of screw geometry on melt temperature profile in single screw extrusion." 2006. http://hdl.handle.net/10454/3917.
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NoExperimental observations of melt temperature profiles and melting performance of extruder screws are reported. A novel temperature sensor consisting of a grid of thermocouple junctions was used to take multiple temperature readings in real time across melt flow in a single screw extruder. Melt pressure in the die and power consumption were also monitored. Three extruder screws at a range of screw speeds were examined for a commercial grade of low density polyethylene. Results showed melt temperature fields at low throughputs to be relatively independent of screw geometry with a flat-shaped temperature profile dominated by conduction. At high throughputs, melting performance and measured temperature fields were highly dependent upon screw geometry. A barrier-flighted screw with Maddock mixer achieved significantly better melting than single flighted screws. Low temperature "shoulder" regions were observed in the temperature profiles of single-flighted screws at high throughput, due to late melting of the solid bed. Stability of the melt flow was also dependent upon screw geometry and the barrier-flighted screw achieving flow with lower variation in melt pressure and temperature. Dimensionless numbers were used to analyze the relative importance of conduction, convection, and viscous shear to the state of the melt at a range of extrusion conditions.
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Abeykoon, Chamil, P. J. Martin, K. Li, and Adrian L. Kelly. "Dynamic modelling of die melt temperature profile in polymer extrusion: Effects of process settings, screw geometry and material." 2014. http://hdl.handle.net/10454/10568.
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NoExtrusion is one of the major methods for processing polymeric materials and the thermal homogeneity of the process output is a major concern for manufacture of high quality extruded products. Therefore, accurate process thermal monitoring and control are important for product quality control. However, most industrial extruders use single point thermocouples for the temperature monitoring/control although their measurements are highly affected by the barrel metal wall temperature. Currently, no industrially established thermal profile measurement technique is available. Furthermore, it has been shown that the melt temperature changes considerably with the die radial position and hence point/bulk measurements are not sufficient for monitoring and control of the temperature across the melt flow. The majority of process thermal control methods are based on linear models which are not capable of dealing with process nonlinearities. In this work, the die melt temperature profile of a single screw extruder was monitored by a thermocouple mesh technique. The data obtained was used to develop a novel approach of modelling the extruder die melt temperature profile under dynamic conditions (i.e. for predicting the die melt temperature profile in real-time). These newly proposed models were in good agreement with the measured unseen data. They were then used to explore the effects of process settings, material and screw geometry on the die melt temperature profile. The results showed that the process thermal homogeneity was affected in a complex manner by changing the process settings, screw geometry and material. (C) 2013 Elsevier Inc. All rights reserved.
Book chapters on the topic "Extruder geometry"
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König, Thomas. "Geometry of the Co-Rotating Extruders: Conveying, and Kneading Elements." In Co-Rotating Twin-Screw Extruder, 91–104. München: Carl Hanser Verlag GmbH & Co. KG, 2007. http://dx.doi.org/10.3139/9783446433410.005.
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Spyropoulos, Mary, and Alisa Andrasek. "Material Disruption." In Proceedings of the 2020 DigitalFUTURES, 290–96. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-33-4400-6_27.
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AbstractThis paper examines the role of computational simulation of material processes with robotics fabrication, with the intent of examining its implications for architectural design and construction. Simulation techniques have been adopted in the automotive industry amongst others, advancing their design and manufacturing outputs. At present, architecture is yet to explore the full potential of this technology and their techniques. The need for simulation is evident in exploring the behaviours of materials and their relative properties. Currently, there is a distinct disconnect between the virtual model and its fabricated counterpart. Through research in simulation, we can begin to understand and clearly visualize the relationship between material behaviours and properties that can lead to a closer correlation between the digital design and its fabricated outcome. As the first phase of investigation, the material of clay is used due to its volatile qualities embedded within the material behaviour. The input geometry is constrained to rudimentary extruded forms in order to not obscure the behaviour of the material, but rather allow for it to drive the machine-making process.
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Han, Chang Dae. "Wire-Coating Extrusion." In Rheology and Processing of Polymeric Materials: Volume 2: Polymer Processing. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195187830.003.0010.
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The process of coating a wire with a polymeric material is basically an extrusion operation in which either the molten polymer is extruded continuously over an axially moving wire or the wire is pulled through the extruded molten polymer. As schematically shown in Figure 5.1, the typical wire-coating unit consists of a pay-off device, a wire preheater, an extruder equipped with a cross-head die, a cooling trough, and a take-off device. Various control and measuring instruments are utilized in the commercial line (Griff 1962). The two basic wire-coating dies are pressure-type dies and tubing-type dies, as shown schematically in Figure 5.2. The tubing-type dies are annular in cross-section. The flow geometry outside the tubing die is important from the point of view of obtaining a coating with better mechanical and electrical properties and surface smoothness. However, little effort has been spent on studying this particular aspect of the process. The pressure-type wire-coating die is an annulus, the side surface of which is the wire to be coated, moving at a constant speed. The flow through this type of die is analogous to the flow through an annulus formed by coaxial cylinders with the inner cylinder moving in the axial direction. In the past, analysis of wire-coating extrusion for pressure-type die has been carried out for Newtonian and power-law fluids (Bagley and Storey 1963; Bernhardt 1962; Carley et al. 1979; Han and Rao 1978; McKelvey 1963). Like in the film coextrusion process presented in Chapter 9, in wire-coating coextrusion two different polymers may be concentrically coated on the wire in a single step (LeNir 1974). Tough abrasive-resistant nylon, for example, can be coated over a much less expensive polyethylene core, or one can have a thin coat of color compound over unpigmented insulator, thus taking advantage of the different properties of two components at a reduced cost. Considerable savings in the cost of processing can be achieved by applying two coats in a single step.
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José Salvador Tomassini, Carlos. "Design, Simulation, and Analysis of the Extrusion Process of a PVC Thermoplastic Profile to Optimize the Design of the Die and the Machine Parameters." In Fiber-Reinforced Plastics. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.100909.
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The objective of this work is to verify the design of an existing die for the manufacture of an extruded profile using the simulation of the flow in the head using a simulation software that uses computational fluid dynamics and also the experimental design and construction of a calibrator by means of the extrusion the geometry and desired dimensions of the profile. The rheological behavior of rigid PVC in the extruded molten state was investigated, which in itself is a difficult target due to the intrinsic weakness of this polymer that degrades when heated above 140°C. By means of a special capillary rheometer, rheological data, k and n of the power law, were obtained to introduce them, together with the process input parameters and the flow channel geometry in the simulation software. The flow channel was drawn with the head and calibrator using CAD-3D software. The different parts of the calibrator were manufactured and assembled into the equipment. The extrusion was performed with the process parameters: screw speed and material temperature used in the simulation software. The results obtained by the extrusion, geometry and final dimensions of the profile, mass flow, pressure, and temperature in the head were compared with those delivered by the software, being the same satisfactory.
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"Extrusion Die and Tooling." In Aluminum Extrusion Technology, 87–118. ASM International, 2000. http://dx.doi.org/10.31399/asm.tb.aet.t68260087.
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Abstract This chapter familiarizes readers with the design, configuration, and function of tooling and dies used to extrude aluminum alloys. It discuses basic design considerations, including the geometry, location, and orientation of die openings; allowances for thermal shrinkage, stretching, and deflection; and the length and profile of bearing surfaces. It outlines the steps and processes involved in die making, describes the selection and treatment of die materials, and examines the factors that influence friction and wear. It also discusses the general procedures for on-site die correction.
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Han, Chang Dae. "Foam Extrusion." In Rheology and Processing of Polymeric Materials: Volume 2: Polymer Processing. Oxford University Press, 2006. http://dx.doi.org/10.1093/oso/9780195187830.003.0015.
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There are two processes used in the production of thermoplastic foams, namely, foam extrusion and structural foam injection molding (Benning 1969; Frisch and Saunders 1973). Foam extrusion, in which either chemical or physical blowing agents are used, is the focus of this chapter. Investigations of foam extrusion have dealt with the type and choice of process equipment (Collins and Brown 1973; Knau and Collins 1974; Senn and Shenefiel 1971; Wacehter 1970), the effect of die design (Fehn 1967; Han and Ma 1983b), the effect of blowing agents on foaming characteristics (Burt 1978, 1979; Han and Ma 1983b; Hansen 1962; Ma and Han 1983), and relationships between the foam density, cell geometry, and mechanical properties (Croft 1964; Kanakkanatt 1973; Mehta and Colombo 1976; Meinecke and Clark 1973). Chemical blowing agents are generally low-molecular-weight organic compounds, which decompose at and above a critical temperature and thereby release a gas (or gases), for example, nitrogen, carbon dioxide, or carbon monoxide. Examples of physical blowing agents include nitrogen, carbon dioxide, fluorocarbons (e.g., trichlorofluoromethane, dichlorodifluoromethane, and dichlorotetrafluoroethane), pentane, etc. They are introduced as a component of the polymer charge or under pressure into the molten polymer in the barrel of the extruder. It is extremely important to control the formation and growth of gas bubbles in order to produce foams of uniform quality (i.e., uniform cell structure). The fundamental questions one may ask in thermoplastic foam processing are: (1) What is the optimal concentration of blowing agent in order to have the minimum number of open cells and thus the best achievable mechanical property? (2) How many bubbles will be nucleated at the instant of nucleation? (3) What is the critical pressure at which bubbles nucleate in a molten polymer? (4) What are the processing–property relationships in foam extrusion and structural foam injection molding? Understandably, the answers to such questions depend, among many factors, on: (1) the solubility of the blowing agent in a molten polymer, (2) the diffusivity of the blowing agent in a molten polymer, (3) the concentration of the blowing agent in the mixture with a molten polymer, (4) the chemical structure of the polymers, (5) the initial pressure of the system, and (6) the equilibrium (or initial) temperature of the system.
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Mahale, Rayappa Shrinivas, Gangadhar M. Kanaginahal, Shamanth Vasanth, Vivek Kumar Tiwary, Rajendrachari Shashanka, Sharath P. C., and Adarsh Patil. "Applications of Fused Deposition Modeling in Dentistry." In Advances in Chemical and Materials Engineering, 211–19. IGI Global, 2023. http://dx.doi.org/10.4018/978-1-6684-6009-2.ch012.
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Fused deposition modelling (FDM) is a popular additive manufacturing (AM) technique for modelling, prototyping, and production. FDM is a technology that creates three-dimensional things directly from three-dimensional CAD data. Layer by layer, thermoplastic material is extruded by a temperature-controlled head. FDM, also known as fused filament fabrication (FFF), is a simple and low-cost method of additive manufacturing that was first introduced in 1989. A thermoplastic filament is fed to a heated nozzle in the FFF process. The material is melted here, and the material is deposited as the nozzle travels layer by layer in the x and y axes along the geometry. FDM has proved beneficial in the medical field to produce more naturalistic models for educational, training, and research reasons, as well as treatment and surgical planning.
Conference papers on the topic "Extruder geometry"
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Cleeman, Jeremy, Alex Bogut, Brijesh Mangrolia, Adeline Ripberger, Arad Maghouli, Kunal Kate, and Rajiv Malhotra. "Multiplexed 3D Printing of Thermoplastics." In ASME 2022 17th International Manufacturing Science and Engineering Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/msec2022-80882.
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Abstract Extrusion-based additive manufacturing of large thermoplastic structures has significant emerging applications. The most popular approach to economically achieving such 3D printing is to increase the polymer flow rate along with the layer height and line width. However, this creates a fundamental compromise between the achievable geometric fidelity and the printing throughput. We explore a Multiplexed Fused Filament Fabrication (MF3) approach in which an array of FFF extruders concurrently prints different sections of the same part using small layer heights and line widths. Mounting all the extruders on one cartesian gantry without individual control of each extruder’s motion enables simple machine construction and control. 3D geometric complexity is realized by rastering the extruder array across the smallest rectangle bounding each 2D layer and by spatially specific deposition via “dynamic” filament retraction/ advancement in the extruders. The dynamic moniker is because, unlike conventional single extruder FFF, the extruder array does not stop during dynamic filament retraction/advancement. This achieves higher throughput at greater resolution without material-intensive overprinting and machining, geometrically-limited throughput of the dual-extruder strategy, cost and geometric limitations of robot-based multiplexing, and the complexity and geometric limitations of previous gantry-based multiplexing efforts. Our experiments reveal the parameters that affect dynamic retraction and advancement, and show a previously unknown coupling between the efficacy of dynamic filament retraction and dynamic filament advancement. We create part-scale thermal simulations to model temperature evolution in the part under the action of multiple concurrently acting extruders, revealing a unique temperature history that can affect bonding and mechanical properties. We show that MF3 can enable resilience to extruder failure by allowing other extruders to take over part fabrication while the damaged extruder is being replaced. We also demonstrate that MF3 enables flexibility in part scale and geometry, i.e., the ability to make multiple smaller parts of similar or distinct geometries in one production run and lesser number of larger parts of similar or distinct geometries in the next production run. Finally, we quantitatively analyze the future potential of MF3 to achieve similar or greater throughput than state-of-the-art Big Area Additive Manufacturing while significantly enhancing the geometric resolution.
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Giaier, Kevin S., David H. Myszka, Wesley P. Kramer, and Andrew P. Murray. "Variable Geometry Dies for Polymer Extrusion." In ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-38409.
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This paper presents the development of variable geometry dies that enable the extrusion of plastic parts with a varying cross section. Extrusion accounts for 40% of all manufactured plastic parts because it is a relatively low-cost and high-production-rate process. Conventional polymer extrusion technology, however, is limited to fixed dies that produce continuous plastic products of constant cross section defined by the die exit profile. A shape-changing die allows the cross section of the extruded part to change over its length, thereby introducing the capacity to manufacture plastic faster and with lower tooling costs than injection molding. This paper discusses design guidelines that were developed for movable die features including revolute and prismatic joint details, land length, and the management of die leakage. To assess these guidelines, multiple dies have been designed and constructed to include an arbitrary four-sided exit profile where changes were made to the internal angles and length of sides as the extruder was operating. Experimental studies were conducted by using different extruder line settings and time between die movements. Test results are presented that include shape repeatability and the relationship between extrudate profile and die exit geometry.
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Ozsipahi, Mustafa, Sertac Cadirci, and Hasan Gunes. "Numerical and Analytical Investigation of Viscous Fluids in a Screw Extruder." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-66124.
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This study presents a flow model for a single screw extruder which has been investigated by means of analytical and numerical methods. Flow phenomena in single screw extruders has evoked attention of many researchers since non-Newtonian type of fluid transport by an extruder is utilized in many industrial applications. In this study we focused on the Newtonian-type of fluid transport by a single screw extruder since we aimed to generate an analytical model for the simplified Navier-Stokes equations under certain boundary conditions. The analytical model for a steady, laminar, isothermal and incompressible flow is derived using integral transform technique for a highly viscous flow where the convective acceleration terms are assumed to be negligible. Numerical investigation is conducted by an incompressible, laminar, finite volume based flow solver using a Volume of Fluid (VoF) approximation. An appropriate single-screw extruder model is used for the simulations. The novelty of the study relies on the usage of a simplified analytical model for a highly viscous flow and the comparison between the analytical and numerical results where the numerical results are obtained by a two-phase flow solver for the full Navier-Stokes equations using the complex extruder geometry.
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Matsumoto, Koki, Natsuki Kayamori, Tatsuya Tanaka, and Yoshihiko Arao. "The optimization of Blister Disk geometry for mixing performance in co-rotating twin-screw extruder." In PROCEEDINGS OF PPS-30: The 30th International Conference of the Polymer Processing Society – Conference Papers. AIP Publishing LLC, 2015. http://dx.doi.org/10.1063/1.4918386.
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Sun, Yong Kweon, and Yong Kyun Kim. "ENHANCEMENT OF HEAT TRANSFER BY CHAOTIC ADVECTION IN A SINGLE SCREW EXTRUDER WITH A STAGGERED FLIGHT GEOMETRY." In International Heat Transfer Conference 11. Connecticut: Begellhouse, 1998. http://dx.doi.org/10.1615/ihtc11.2030.
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Zhao, Donghua, and Weizhong Guo. "Research on Curved Layer Fused Deposition Modeling (CLFDM) With Variable Extruded Filament (VEF)." In ASME 2018 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/detc2018-85343.
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Fused Deposition Modeling (FDM), an Additive Manufacturing (AM) technique, is widely used due to its low-cost and open source. Geometry accuracy and strength performance of the printed parts are closely related to inter-layer bonding between adjacent layers and inter-road bonding in the layer. Because of the limit of layer-based AM, the longitudinal tensile strength of the filaments is much higher than the bonding strength between adjacent filaments, which brings anisotropy of the printed part. While CLFDM is devoted to solve this problem and obtain better geometry accuracy and meanwhile decrease build time by virtue of high continuity of filament, reduced stair-step effect, and lesser number of layers, especially when manufacturing thin and curved parts (shells). However, to the best of our knowledge in the aspects of process modeling of CLFDM, available researches focus mainly on simple curved layer, instead of more intricate ones possessing tiny features, which are more common in manufacturing. Therefore, to realize Solid Freeform Fabrication (SFF), this paper researches CLFDM with VEF (simultaneously changing the direction and the dimension of extruded filament according to manufacturing demand of the curved layer), which would be a fundamental study and a foundation for Advanced Design for Additive Manufacturing (ADFAM), slicing and path planning (extruder path generation) in 3D space. To realize slicing and printing with homogeneous and inhomogeneous extruded filament between consecutive layers and within the layer (flat or curved), models of flat layer FDM and CLFDM with VEF are respectively established. Then, the relationships among key process parameters are analyzed. Finally, graphical simulation of the proposed strategy based on a vase is provided to verify its effectiveness and advantages from a theoretical point of view. In general, variable direction of extruded filament along tangential directions of part surface imparts smoother surfaces, instead of rough exterior appearance resulting from stair-step effects. And variable dimension of extruded filament maximizes material extruded to increase build speed wherever allowed and minimizes deposition size for resolution whenever needed, resulting in curved layer surfaces with uneven layer thickness and having tiny features.
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Li, Ke, Han-Xiong Huang, and Guo Jiang. "Co-Effect of Chaotic Mixing and Clay on Morphology Development of Polypropylene/Polyamide 6 Blends Along Extruder." In ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-68589.
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Morphology development of polypropylene (PP)/polyamide 6 (PA6) (60/40 w/w) blends and their nanocomposites with 5 wt% clay along an extruder during compounding was investigated in this work. Two screw geometries were used. One was a conventional geometry, and the other one was a special geometry which was used to induce chaotic mixing. The scanning electron microscopy (SEM) of blends indicated that chaotic mixing facilitated to form thinner laminar layers and co-continuous phase structure. The co-continuous phase structure became uniform as the co-effect of chaotic mixing and clay. Transmission electron microscopy (TEM) results showed that the clay platelets dispersed in the PP phase initially migrated into PA6 phase. In addition, chaotic mixing made a better dispersion of clay in PA6 phase than conventional mixing. Rheological test results showed that the dynamic elastic modulus for the sample with co-continuous phase structure presented a solid-like response at lower frequencies.
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Stewart, Samuel R., John E. Wentz, and Joseph T. Allison. "Experimental and Computational Fluid Dynamic Analysis of Melt Flow Behavior in Fused Deposition Modelling of Poly(lactic) Acid." In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-52261.
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Fused deposition modelling (FDM) creates three-dimensional parts by feeding a rigid thermoplastic filament through a heated barrel to achieve a semi-fluid state and then extruding it layer-by-layer to create a part geometry. The melt flow behavior within FDM must be analyzed in order to correctly understand the temperature gradients within the system to promote part quality, process control, and efficiency. The presented research consists of analyzing the melt flow behavior of polymer poly(lactic) acid (PLA) within FDM. This includes an experimental analysis of the power output of the resistive heat source, a theoretical analysis of external coefficients of heat-transfer, and an experimental validation of liquefier temperatures. A three-dimensional fluid-flow model is created using the accurate geometry of the extruder assembly, calculated conditions from initial experimental results, and referenced material properties. Results of this research include a significant temperature difference between the areas of the liquefier assembly close in proximity to the power source to those further away such as the inlet and outlet, suggesting that external heat transfer mechanisms play a significant role in liquefier dynamics, contrary to the more common assumption of constant wall temperature or constant heat flux used in modeling. The research presented provides new information regarding the melt flow of PLA, a method of modeling external heat transfer, and a way of understanding power consumption that can lead to liquefier design improvements. The process itself will also aid in identifying modeling considerations for further investigations of melt flow involving various extruder designs and material options. Specifically, the use of this type of comprehensive model is of interest to the additive manufacturing community with respect to thermally sensitive component specification and heating and cooling needs within process based on changing system parameters such as extrusion temperature and mass flow rates (i.e. material feed rate and/or change in extrusion diameter).
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Simon, Timothy R., Giovanny A. Aguilera, and Fu Zhao. "Characterization of Particle Emission From Fuse Deposition Modeling Printers." In ASME 2017 12th International Manufacturing Science and Engineering Conference collocated with the JSME/ASME 2017 6th International Conference on Materials and Processing. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/msec2017-3007.
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Throughout the past decade the popularity of additive manufacture (AM) has grown tremendously. Although AM has been deemed as an environmentally friendly alternative to traditional processes, there have already been several studies done showing that AM processes can affect human health and the environment by emitting particles of a dynamic size range into its surrounding during a print. The objective of this paper is to look deeper into the issue of particle emissions from one of the most popular AM processes i.e. fused deposition modeling (FDM). Particle emissions from a Makeblock 3-D printer enclosed in a chamber and placed in a Class 1 cleanroom are measured using a high temporal resolution electrical low pressure impactor (ELPI) which takes close-to-real-time measurements of particles in the range of 6–200nm. A honeycomb cube with side length 1.25” and the NIST standard testing part are printed using acrylonitrile butadiene styrene (ABS) filament. Results show that particle emissions are closely related to the filament residence time in the extruder while less related to extruding speed. The initial spike of particle concentration right after printing starts is likely due to the long time needed to heat the extruder and the bed to the desired temperature. It is suggested that part geometry/features and build path could significantly affect particle emissions. TEM images suggest that particles may be formed through vapor condensation and coagulation of small particles.
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Chen, Hongrui, and Xingchen Liu. "Enhanced Toolpath Planning for Fused Filament Fabrication." In ASME 2020 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/detc2020-22725.
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Abstract The slicing software process the 3D geometry into 2D slices and toolpaths for additive manufacturing processes. Most slicing software allows users to select from an array of infill patterns and to specify the overall infill volume fraction globally. However, the ability to locally control the volume fraction, and mechanical properties, is often limited. In this paper, we propose a novel toolpath enhancing algorithm to enable the local control on the volume fraction of various stock and custom infill patterns. In particular, the algorithm widens the infill pattern by directly modifying their toolpath with connected Fermat curves. By preserving the topology of the original toolpath, the connected Fermat curve not only produces predictable boosts in part performance but also minimized the printing time by eliminating extruder traversals without material deposition. The field that controls local volume fraction can be designed either manually or through optimization. The effectiveness of the proposed approach in toolpath generation is demonstrated through volume fraction fields designed by both approaches.