Based on analyzing the influences of a slicing scheme on stair-stepping effect, supporting structure, efficiency and deformation, etc. , analytical hierarchical process （AHP） combining with fuzzy synthetic evaluatio...Based on analyzing the influences of a slicing scheme on stair-stepping effect, supporting structure, efficiency and deformation, etc. , analytical hierarchical process （AHP） combining with fuzzy synthetic evaluation is introduced to make decision in slicing schemes for a processing part. The application in determining the slicing scheme for a computer mouse during prototyping shows that the method increases the rationality during decision- making and improves quality and efficiency for the prototyping part.展开更多
Fused deposition modelling(FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials ...Fused deposition modelling(FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials is proposed. First of all, according to the manufacturing process of FDM, orthotropic constitutive model is used to describe the mechanical behavior. Then the virtual fields method(VFM) is applied to characterize all the mechanical parameters(Q, Q, Q, Q) using the full-field strain,which is measured by digital image correlation(DIC). Since the principal axis of the FDM-fabricated structure is sometimes unknown due to the complexity of the manufacturing process, a disk in diametrical compression is used as the load configuration so that the loading angle can be changed conveniently. To verify the feasibility of the proposed method, finite element method(FEM) simulation is conducted to obtain the strain field of the disk. The simulation results show that higher accuracy can be achieved when the loading angle is close to 30?. Finally, a disk fabricated by FDM was used for the experiment. By rotating the disk, several tests with different loading angles were conducted. To determine the position of the principal axis in each test, two groups of parameters(Q, Q, Q, Q) are calculated by two different groups of virtual fields. Then the corresponding loading angle can be determined by minimizing the deviation between two groups of the parameters. After that, the four constants(Q, Q, Q, Q) were determined from the test with an angle of 27?.展开更多
Fused deposition modelling (FDM) is one of rapid prototyping (RP) technologies which uses an additive fabrication approach.Each commercially available FDM model has different types of process parameters for different ...Fused deposition modelling (FDM) is one of rapid prototyping (RP) technologies which uses an additive fabrication approach.Each commercially available FDM model has different types of process parameters for different applications.Some of the desired parts require excellent surface finish as well as good tolerance.The most common parameters requiring setup are the raster angle,tool path,slice thickness,build orientation,and deposition speed.The purpose of this paper is to discuss the process parameters of FDM Prodigy Plus (Stratasys,Inc.,Eden Prairie,MN,USA).Various selected parameters were tested and the optimum condition was proposed.The quality of the parts produced was accessed in terms of dimensional accuracy and surface finish.The optimum parameters obtained were then applied in the fabrication of the master pattern prior to silicone rubber moulding (SRM).These parameters would reduce the post processing time.The dimensional accuracy and surface roughness were analyzed using coordinate measuring machine (CMM) and surface roughness tester,respectively.Based on this study,the recommended parameters will improve the quality of the FDM parts produced in terms of dimensional accuracy and surface roughness for the application of SRM.展开更多
Biodegradable polymers are highly attractive as potential alternatives to petroleum-based polymers in an attempt to achieve carbon neutrality whilst maintaining the mechanical properties of the structures.Among these ...Biodegradable polymers are highly attractive as potential alternatives to petroleum-based polymers in an attempt to achieve carbon neutrality whilst maintaining the mechanical properties of the structures.Among these polymers,polylactic acid(PLA)is particularly promising due to its good mechanical properties,biocompatibility and thermoplasticity.In this work,we aim to enhance the mechanical properties of PLA using mechanically-defibrated cellulose nanofibers(CNFs)that exhibit remarkable mechanical properties and biodegradability.We also employ fused deposition modeling(FDM),one of the three-dimensional printing methods for thermoplastic polymers,for the low-cost fabrication of the products.Mechanically-defibrated CNF-reinforced PLA matrix composites are fabricated by FDM.Their tensile properties are investigated in two printing directions(0°/90°and+45°/-45°).The discussion about the relationship between printing direction and tensile behavoir of mechanically-defibrated CNF-reinforced PLA matrix composite is the unique point of this study.We further discuss the microstructure and fracture surface of mechanically-defibrated CNF-reinforced PLA matrix composite by scanning electron microscope.展开更多
To aim at prototype parts fabricated with fused deposition modeling(FDM)process,the problems how to improve and enhance their surface micro-precision are studied.The producing mechanism of surface roughness is explain...To aim at prototype parts fabricated with fused deposition modeling(FDM)process,the problems how to improve and enhance their surface micro-precision are studied.The producing mechanism of surface roughness is explained with three aspects concretely including the principle error of rapid prototyping(RP)process,the inherent characteristics of FDM process,and some mi-cro-scratches on the surface of the extruded fiber.Based on the micro-characters of section shape of the FDM prototype,a physical model reflecting the outer shape characters is abstracted.With the physical simplified and deduced,the evaluating equations of surface roughness are acquired.According to the FDM sample parts with special design for experimental measurement,the real surface roughness values of different inclined planes are obtained.And the measuring values of surface roughness are compared with the calculation values.Furthermore,the causes of surface roughness deviation between measuring values and calculation values are respectively analyzed and studied.With the references of analytic conclusions,the measuring values of the experimental part surface are revised,and the revised values nearly accord with the calculation values.Based on the influencing principles of FDM process parameters and special post processing of FDM prototype parts,some concrete measures are proposed to reduce the surface roughness of FDM parts,and the applying effects are better.展开更多
A novel fiber Bragg grating(FBG)sensor with three-dimensional(3D)fused deposition modeling(FDM)approach is proposed for effective stress measurement in soil mass.The three-diaphragm structure design is developed to me...A novel fiber Bragg grating(FBG)sensor with three-dimensional(3D)fused deposition modeling(FDM)approach is proposed for effective stress measurement in soil mass.The three-diaphragm structure design is developed to measure earth and water pressures simultaneously.The proposed transducer has advantages of small size,high sensitivity,low cost,immunity to electromagnetic interference and rapid prototyping.The working principle,design parameters,and manufacturing details are discussed.The proposed transducer was calibrated for earth and water pressures measurement by using weights and a specially designed pressure chamber,respectively.The calibration results showed that the wavelength of the transducer was proportional to the applied pressure.The sensitivity coefficients of the earth and water pressures were 12.633 nm/MPa and 6.282 nm/MPa,respectively.Repeated tests and error analysis demonstrated the excellent stability and accuracy of the earth and water pressure measurements.The performance of the proposed transducer was further verified by a model experimental test and numerical analysis,which indicated that the proposed transducer has great potential for practical applications.展开更多
Although several research works in the literature have focused on studying the capabilities of additive manufacturing(AM) systems, few works have addressed the development of Design for Additive Manufacturing(DfAM) kn...Although several research works in the literature have focused on studying the capabilities of additive manufacturing(AM) systems, few works have addressed the development of Design for Additive Manufacturing(DfAM) knowledge,tools, rules, and methodologies, which has limited the penetration and impact of AM in industry. In this paper a comprehensive review of design and manufacturing strategies for Fused Deposition Modelling(FDM) is presented.Consequently, several DfAM strategies are proposed and analysed based on existing research works and the operation principles, materials, capabilities and limitations of the FDM process. These strategies have been divided into four main groups: geometry, quality, materials and sustainability. The implementation and practicality of the proposed DfAM is illustrated by three case studies. The new proposed DfAM strategies are intended to assist designers and manufacturers when making decisions to satisfy functional needs, while ensuring manufacturability in FDM systems.Moreover, many of these strategies can be applied or extended to other AM processes besides FDM.展开更多
Ideal tissue engineering scaffolds need interconnected pores and high porosity to enable cell survival,migration,proliferation,and differentiation.However,obtaining a high-resolution structure is difficult with tradit...Ideal tissue engineering scaffolds need interconnected pores and high porosity to enable cell survival,migration,proliferation,and differentiation.However,obtaining a high-resolution structure is difficult with traditional one-temperature control fused deposition modeling(FDM).In this study,we propose a dual-temperature control method to improve printability.A numerical model is developed in which the viscosity is a function of temperature and shear rate to study the influence of two different temperature control modes.Quantitative tests are used to assess filament formation and shape fidelity,including one-dimensional filament printing,deposition at corners,fusion,and collapse.By using dual-temperature control,the width of the deposited poly(ε-caprolactone)filament is reduced to 50μm.The comparative results of both the experimental method and numerical simulation suggest that the dual-temperature control FDM can manufacture spatially arranged constructs and presents a promising application in tissue engineering。展开更多
Fused deposition modeling(FDM) is one of the latest rapid prototyping techniques in which parts can be manufactured at a fast pace and are manufactured with a high accuracy. This research work is carried out to study ...Fused deposition modeling(FDM) is one of the latest rapid prototyping techniques in which parts can be manufactured at a fast pace and are manufactured with a high accuracy. This research work is carried out to study the friction and wear behavior of parts made of newly developed Nylon6-Fe composite material by FDM. This work also involves the comparison of the friction and wear characteristics of the Nylon6-Fe composite with the existing acrylonitrile butadiene styrene(ABS) filament of the FDM machine. This Is carried out on the pin on disk setup by varying the load(5, 10, 15 and 20 N) and speed(200 and 300 r/min). It is concluded that the newly developed composite is highly wear resistant and can be used in industrial applications where wear resistance is of paramount importance. Morphology of the surface in contact with the Nylon6-Fe composite and ABS is also carried out.展开更多
A new particle deposition model, namely partial deposition model, is developed in order to improve the accuracy of prediction to particle deposition. Concepts of critical velocity and critical angle are proposed and u...A new particle deposition model, namely partial deposition model, is developed in order to improve the accuracy of prediction to particle deposition. Concepts of critical velocity and critical angle are proposed and used to determine whether particles are deposited or not. The comparison of numerical results calculated by partial deposition model and existing deposition model shows that the deposition distribution obtained by partial deposition model is more reasonable. Based on the predicted deposition results, the change of total pressure loss coefficient with operating time and the distribution of pressure coefficients on blade surface after 500 hours are predicted by using partial deposition model.展开更多
The paper discusses the mechanical and thermal performance manifested in natural nanorods attapulgite(ATP)reinforced Acrylonitrile butadiene styrene(ABS)nanocomposites in the process of fused deposition modeling(FDM)....The paper discusses the mechanical and thermal performance manifested in natural nanorods attapulgite(ATP)reinforced Acrylonitrile butadiene styrene(ABS)nanocomposites in the process of fused deposition modeling(FDM).Molten extrusion technique was taken to manufacture the filaments of ABS/organic-attapulgite(OAT)nanocomposites with different mass fraction and the printing operation was made by one commercial FDM three-dimensional(3D)printer.Results indicate that the mechanical performance of these FDM 3D printed specimens are improved obviously via the introduction of OAT,and tensile strength of the ABS/OAT nanocomposites parts with only 2 wt%OAT addition is enhanced by 48.1%.At the same time,the addition OAT can reduce the linear expansion coefficient and creep flexibility,and improve the thermal stability and dimensional accuracy of these FDM 3D printed parts.展开更多
Naturalfibre as a reinforcing agent has been widely used in many industrial applications.Nevertheless,several factors need to be considered,such as the size and weight percentage of thefibre used in binding.Using fused ...Naturalfibre as a reinforcing agent has been widely used in many industrial applications.Nevertheless,several factors need to be considered,such as the size and weight percentage of thefibre used in binding.Using fused deposition modelling(FDM),this factor was investigated by varying the size of naturalfibre as the responding variable with afixed weight percentage of kenaffibre.The process of modifying the naturalfibre in terms of size might increase the dispersion of kenaffibre in the polymer matrix and increase the adhesion bonding between thefibre and matrix of composites,subsequently improving the interfacial bonding between these two phases.In this paper,the effect offibre size was evaluated by performing the mechanical test,Scanning Electron Micrograph(SEM)to observe the morphology of the composites,and also by surface analysis.The surface roughness was visualised using a 3D profilometer and thefigure was illustrated as colour shading in the image.The composite withfibre size≤100μm displayed better tensile andflexural strength,compared to other sizes.In conclusion,by reducing the size of thefibre,the composites could develop high strength performance for industrial applications.展开更多
In this study,we investigated warpage and corner lifting minimization for three-dimensional printed parts generated by macro-size fused deposition modeling(FDM).First,the reasons for warpage were theoretically elucida...In this study,we investigated warpage and corner lifting minimization for three-dimensional printed parts generated by macro-size fused deposition modeling(FDM).First,the reasons for warpage were theoretically elucidated.This approach revealed that the thermal deformation and differential volumetric shrinkage of the extruded molten plastic resulted in warpage of FDM parts.In addition,low adhesion between the deposited model and the heated or non-heated printing bed may intensify warpage further.As a next step,initial small-size and medium-size models were used to identify parameters to manage and minimize warpage in a way that would reduce material consumption and running time.Finally,a macro-size model was built to experimentally investigate and verify the technical solutions to minimize the warpage of FDM parts.In conclusion,an improved part with reduced warpage was efficiently produced after detailed consideration of thermal effects and adhesion force.Potential exists to widen the application scope of FDM technology in manufacturing for processes like thermoforming that involve mold core fabrication with heating.This technology,which has applications not only in mechanical engineering but also in related engineering fields,is convenient and could readily be applied to practical manufacturing industries.展开更多
The geometrical model of the filament during the fused deposition modeling (FDM) process was firstly proposed based on three different models, tractrix, parabola, and catenary. Comparing with the actual measured filam...The geometrical model of the filament during the fused deposition modeling (FDM) process was firstly proposed based on three different models, tractrix, parabola, and catenary. Comparing with the actual measured filament curves on the Stratasys 1600 FDM machine, it is indicated that the tractrix model had the best agreement with the actual measured curves. With the analytical simulation, the nozzle trajectories in the straight-line deposition road, circle road, and arbitrary continuous curve road were deduced, according to the traxtric based geometrical model of the filament.展开更多
The urgent need to develop customized functional products only possible by 3D printing had realized when faced with the unavailability of medical devices like surgical instruments during the coronavirus-19 disease and...The urgent need to develop customized functional products only possible by 3D printing had realized when faced with the unavailability of medical devices like surgical instruments during the coronavirus-19 disease and the ondemand necessity to perform surgery during space missions.Biopolymers have recently been the most appropriate option for fabricating surgical instruments via 3D printing in terms of cheaper and faster processing.Among all 3D printing techniques,fused deposition modelling(FDM)is a low-cost and more rapid printing technique.This article proposes the fabrication of surgical instruments,namely,forceps and hemostat using the fused deposition modeling(FDM)process.Excellent mechanical properties are the only indicator to judge the quality of the functional parts.The mechanical properties of FDM-processed parts depend on various process parameters.These parameters are layer height,infill pattern,top/bottom pattern,number of top/bottom layers,infill density,flow,number of shells,printing temperature,build plate temperature,printing speed,and fan speed.Tensile strength and modulus of elasticity are chosen as evaluation indexes to ascertain the mechanical properties of polylactic acid(PLA)parts printed by FDM.The experiments have performed through Taguchi’s L27orthogonal array(OA).Variance analysis(ANOVA)ascertains the significance of the process parameters and their percent contributions to the evaluation indexes.Finally,as a multiobjective optimization technique,grey relational analysis(GRA)obtains an optimal set of FDM process parameters to fabricate the best parts with comprehensive mechanical properties.Scanning electron microscopy(SEM)examines the types of defects and strong bonding between rasters.The proposed research ensures the successful fabrication of functional surgical tools with substantial ultimate tensile strength(42.6 MPa)and modulus of elasticity(3274 MPa).展开更多
The employment of natural fibres in fused deposition modeling has raised much attention from researchers in finding a suitable formulation for the natural fibre composite filaments.Moreover,selection of suitable natur...The employment of natural fibres in fused deposition modeling has raised much attention from researchers in finding a suitable formulation for the natural fibre composite filaments.Moreover,selection of suitable natural fibres for fused deposition modeling should be performed before the development of the composites.It could not be performed without identifying selection criteria that comprehend both materials and fused deposition modeling process requirements.Therefore,in this study,integration of the Analytic Hierarchy Process(AHP)/Analytic Network Process(ANP)has been introduced in selecting the natural fibres based in different clusters of selection concurrently.The selection process has been performed based on the interdependency among the selection criteria.Pairwise comparison matrices are constructed based on AHP’s hierarchical model and super matrices are constructed based on the ANP’s network model.As a result,flax fibre has ranked at the top of the selection by scored 19.5%from the overall evaluation.Flax fibre has excellent material properties and been found in various natural fibre composite applications.Further investigation is needed to study the compatibility of this fibre to be reinforced with a thermoplastic polymer matrix to develop a resultant natural fibre composite filament for fused deposition modeling.展开更多
FDM （fused deposition modeling） has become popular among Additive Manufacturing technologies due to its speed, geometric scalability, and low cost; however, the primitive nature of the FDM build surface fundamentall...FDM （fused deposition modeling） has become popular among Additive Manufacturing technologies due to its speed, geometric scalability, and low cost; however, the primitive nature of the FDM build surface fundamentally limits the utility of FDM in terms of reliability, autonomy, and material selection. Currently, FDM relies on adhesive forces between the first layer of a print and the build surface; depending on the materials involved, this adhesive bond may or may not be reliable. Thermal contraction between the build plate and build materials can break that bond, which causes warpage and delamination of the part from the build surface and subsequent failure of the part. Furthermore, with each print, the user must use tools or manual maneuvering to separate the printed part from the build surface as well as retexture or replace the used build surface. In this paper, we present a novel build platform that allows for a mechanical bond between the print and build surface by using dovetail-shaped features. The first layer of the print flows into the features and becomes mechanically captivated by the build platform. Once the print is completed, the platform is rolled or flexed open to release the part from the mechanical bond. This design not only lowers the risk of delamination during printing but also eliminates the need for a user to reset or replace the build surface between print jobs. The effectiveness of each geometry was determined by measuring the distance at the pinch point compared to the distance that the extrusion filled below the pinch point. The captivation ratio was measured to compare the different geometries tested and determine which direction of extrusion creates a better ratio.展开更多
Integrating extrusion-based fused deposition modeling(FDM)with advancements in conductive thermoplastic materials is fostering innovation in the fabrication of sensors,electrodes,and printable electronics.This review ...Integrating extrusion-based fused deposition modeling(FDM)with advancements in conductive thermoplastic materials is fostering innovation in the fabrication of sensors,electrodes,and printable electronics.This review presents an in-depth analysis of the advantages and disadvantages of FDM compared to other additive manufacturing(AM)techniques,focusing on its unique capacity to create functional components.Various materials,including host materials and conductive filaments,both commercial and custom-made,are examined for their suitability in conductive component fabrication.The impact of key process parameters,such as pre-printing settings,printing parameters(e.g.,layer thickness,infill density and pattern,print speed,extrusion width,raster angle and orientation,and bed temperature),and post-printing settings on the performance of conductive filaments is also discussed.The review highlights the working principles and applications of different types of sensors printed using FDM,including strain,pressure,temperature,and acceleration sensors,the fabrication of electrodes for physiological and electrochemical monitoring,showcasing the potential of FDM to integrate multifunctional sensing capabil-ities in a single build.Finally,the review explores the future prospects of FDM in sensor and electrode manufacturing,identifying key challenges that need to be overcome to further enhance the technology's potential in advanced applications.展开更多
The black shales of Wufeng and Longmaxi Formation(Late Ordovician-Early Silurian period)in Sichuan Basin are the main strata for marine shale gas exploration,which have a yearly shale gas production of 228×10^(8)...The black shales of Wufeng and Longmaxi Formation(Late Ordovician-Early Silurian period)in Sichuan Basin are the main strata for marine shale gas exploration,which have a yearly shale gas production of 228×10^(8)m^(3)and cumulative shale gas production of 919×10^(8)m^(3).According to the lithological and biological features,filling sequences,sedimentary structures and lab analysis,the authors divided the Wufeng/Guanyinqiao and Longmaxi Formations into shore,tidal flat,shoal,shallow water shelf and deep water shelf facies,and confirmed that a shallow water deposition between the two sets of shales.Although both Formations contain similar shales,their formation mechanisms differ.During the deposition of Wufeng shale,influenced by the Caledonian Movement,the Central Sichuan and Guizhou Uplifts led to the transformation of the Sichuan Basin into a back-bulge basin.Coinstantaneous volcanic activity provided significant nutrients,contributing to the deposition of Wufeng Formation black shales.In contrast,during the deposition of Longmaxi shale,collisions caused basement subsidence,melting glaciers raised sea levels,and renewed volcanic activity provided additional nutrients,leading to Longmaxi Formation black shale accumulation.Considering the basic sedimentary geology and shale gas characteristics,areas such as Suijiang-Leibo-Daguan,Luzhou-Zigong,Weirong-Yongchuan,and Nanchuan-Dingshan are identified as key prospects for future shale gas exploration in the Wufeng-Longmaxi Formations.展开更多
The lower member of Dalazi Formation is an important oil reservoir in the Songjiang Basin.Based on the research on its field-measured geological profiles,lithological combination characteristics and grain size distrib...The lower member of Dalazi Formation is an important oil reservoir in the Songjiang Basin.Based on the research on its field-measured geological profiles,lithological combination characteristics and grain size distribution characteristics,combined with the analysis of the spatial distribution characteristics,sedimentary structural characteristics and hydrodynamic conditions of the sediments in this member,nine sedimentary microfacies of the fan delta plain subfacies,fan delta front subfacies and littoral-shallow lacustrine subfacies have been identified.The study reveals that lower member of Dalazi Formation in the research area follows a fan delta–shallow lacustrine depositional model in the steep slope zone of a rift lake basin.The sediments primarily originate from the Pre-Mesozoic strata in the steep southeastern and eastern margins.The basin center migrated from the early Xiaoshahe area to the Yangmucun–Shenglicun area,and the sedimentary system gradually transitioned from fan delta to littoral-shallow lacustrine facies.展开更多
基金Supported by the Science and Technology Support Key Project of Jiangsu Province (DE2008365)~~
文摘Based on analyzing the influences of a slicing scheme on stair-stepping effect, supporting structure, efficiency and deformation, etc. , analytical hierarchical process （AHP） combining with fuzzy synthetic evaluation is introduced to make decision in slicing schemes for a processing part. The application in determining the slicing scheme for a computer mouse during prototyping shows that the method increases the rationality during decision- making and improves quality and efficiency for the prototyping part.
基金the financial support from the National Natural Science Foundation of China (Grants 11672153, 11232008, and 11227801)
文摘Fused deposition modelling(FDM), a widely used rapid prototyping process, is a promising technique in manufacturing engineering. In this work, a method for characterizing elastic constants of FDM-fabricated materials is proposed. First of all, according to the manufacturing process of FDM, orthotropic constitutive model is used to describe the mechanical behavior. Then the virtual fields method(VFM) is applied to characterize all the mechanical parameters(Q, Q, Q, Q) using the full-field strain,which is measured by digital image correlation(DIC). Since the principal axis of the FDM-fabricated structure is sometimes unknown due to the complexity of the manufacturing process, a disk in diametrical compression is used as the load configuration so that the loading angle can be changed conveniently. To verify the feasibility of the proposed method, finite element method(FEM) simulation is conducted to obtain the strain field of the disk. The simulation results show that higher accuracy can be achieved when the loading angle is close to 30?. Finally, a disk fabricated by FDM was used for the experiment. By rotating the disk, several tests with different loading angles were conducted. To determine the position of the principal axis in each test, two groups of parameters(Q, Q, Q, Q) are calculated by two different groups of virtual fields. Then the corresponding loading angle can be determined by minimizing the deviation between two groups of the parameters. After that, the four constants(Q, Q, Q, Q) were determined from the test with an angle of 27?.
文摘Fused deposition modelling (FDM) is one of rapid prototyping (RP) technologies which uses an additive fabrication approach.Each commercially available FDM model has different types of process parameters for different applications.Some of the desired parts require excellent surface finish as well as good tolerance.The most common parameters requiring setup are the raster angle,tool path,slice thickness,build orientation,and deposition speed.The purpose of this paper is to discuss the process parameters of FDM Prodigy Plus (Stratasys,Inc.,Eden Prairie,MN,USA).Various selected parameters were tested and the optimum condition was proposed.The quality of the parts produced was accessed in terms of dimensional accuracy and surface finish.The optimum parameters obtained were then applied in the fabrication of the master pattern prior to silicone rubber moulding (SRM).These parameters would reduce the post processing time.The dimensional accuracy and surface roughness were analyzed using coordinate measuring machine (CMM) and surface roughness tester,respectively.Based on this study,the recommended parameters will improve the quality of the FDM parts produced in terms of dimensional accuracy and surface roughness for the application of SRM.
基金supported by the Program for Creation of Interdisciplinary Research and Ensemble Program of Frontier Research Institute for Interdisciplinary Sciences,Tohoku University。
文摘Biodegradable polymers are highly attractive as potential alternatives to petroleum-based polymers in an attempt to achieve carbon neutrality whilst maintaining the mechanical properties of the structures.Among these polymers,polylactic acid(PLA)is particularly promising due to its good mechanical properties,biocompatibility and thermoplasticity.In this work,we aim to enhance the mechanical properties of PLA using mechanically-defibrated cellulose nanofibers(CNFs)that exhibit remarkable mechanical properties and biodegradability.We also employ fused deposition modeling(FDM),one of the three-dimensional printing methods for thermoplastic polymers,for the low-cost fabrication of the products.Mechanically-defibrated CNF-reinforced PLA matrix composites are fabricated by FDM.Their tensile properties are investigated in two printing directions(0°/90°and+45°/-45°).The discussion about the relationship between printing direction and tensile behavoir of mechanically-defibrated CNF-reinforced PLA matrix composite is the unique point of this study.We further discuss the microstructure and fracture surface of mechanically-defibrated CNF-reinforced PLA matrix composite by scanning electron microscope.
基金This project is supported by National Natural Science Foundation of China(No.50575139)
文摘To aim at prototype parts fabricated with fused deposition modeling(FDM)process,the problems how to improve and enhance their surface micro-precision are studied.The producing mechanism of surface roughness is explained with three aspects concretely including the principle error of rapid prototyping(RP)process,the inherent characteristics of FDM process,and some mi-cro-scratches on the surface of the extruded fiber.Based on the micro-characters of section shape of the FDM prototype,a physical model reflecting the outer shape characters is abstracted.With the physical simplified and deduced,the evaluating equations of surface roughness are acquired.According to the FDM sample parts with special design for experimental measurement,the real surface roughness values of different inclined planes are obtained.And the measuring values of surface roughness are compared with the calculation values.Furthermore,the causes of surface roughness deviation between measuring values and calculation values are respectively analyzed and studied.With the references of analytic conclusions,the measuring values of the experimental part surface are revised,and the revised values nearly accord with the calculation values.Based on the influencing principles of FDM process parameters and special post processing of FDM prototype parts,some concrete measures are proposed to reduce the surface roughness of FDM parts,and the applying effects are better.
基金funding support from the National Natural Science Foundation of China(Grant Nos.41972271 and 42177127)Sanya Science and Education Innovation Park of Wuhan University of Technology(Grant No.2020KF0007)。
文摘A novel fiber Bragg grating(FBG)sensor with three-dimensional(3D)fused deposition modeling(FDM)approach is proposed for effective stress measurement in soil mass.The three-diaphragm structure design is developed to measure earth and water pressures simultaneously.The proposed transducer has advantages of small size,high sensitivity,low cost,immunity to electromagnetic interference and rapid prototyping.The working principle,design parameters,and manufacturing details are discussed.The proposed transducer was calibrated for earth and water pressures measurement by using weights and a specially designed pressure chamber,respectively.The calibration results showed that the wavelength of the transducer was proportional to the applied pressure.The sensitivity coefficients of the earth and water pressures were 12.633 nm/MPa and 6.282 nm/MPa,respectively.Repeated tests and error analysis demonstrated the excellent stability and accuracy of the earth and water pressure measurements.The performance of the proposed transducer was further verified by a model experimental test and numerical analysis,which indicated that the proposed transducer has great potential for practical applications.
基金Supported by National Science and Technology Council(CONACYT)of Mexico(Grant No.CB-2010-01-154430)PROMEP Program of the Public Education Secretariat(SEP)of MexicoFund for Research Support(FAI)of UASLP
文摘Although several research works in the literature have focused on studying the capabilities of additive manufacturing(AM) systems, few works have addressed the development of Design for Additive Manufacturing(DfAM) knowledge,tools, rules, and methodologies, which has limited the penetration and impact of AM in industry. In this paper a comprehensive review of design and manufacturing strategies for Fused Deposition Modelling(FDM) is presented.Consequently, several DfAM strategies are proposed and analysed based on existing research works and the operation principles, materials, capabilities and limitations of the FDM process. These strategies have been divided into four main groups: geometry, quality, materials and sustainability. The implementation and practicality of the proposed DfAM is illustrated by three case studies. The new proposed DfAM strategies are intended to assist designers and manufacturers when making decisions to satisfy functional needs, while ensuring manufacturability in FDM systems.Moreover, many of these strategies can be applied or extended to other AM processes besides FDM.
基金The authors gratefully acknowledge the support provided by the National Natural Science Foundation of China(Nos.52250006 and 52075482)the Starry Night Science Fund of Zhejiang University Shanghai Institute for Advanced Study(No.SNZJU-SIAS-004).
文摘Ideal tissue engineering scaffolds need interconnected pores and high porosity to enable cell survival,migration,proliferation,and differentiation.However,obtaining a high-resolution structure is difficult with traditional one-temperature control fused deposition modeling(FDM).In this study,we propose a dual-temperature control method to improve printability.A numerical model is developed in which the viscosity is a function of temperature and shear rate to study the influence of two different temperature control modes.Quantitative tests are used to assess filament formation and shape fidelity,including one-dimensional filament printing,deposition at corners,fusion,and collapse.By using dual-temperature control,the width of the deposited poly(ε-caprolactone)filament is reduced to 50μm.The comparative results of both the experimental method and numerical simulation suggest that the dual-temperature control FDM can manufacture spatially arranged constructs and presents a promising application in tissue engineering。
基金PTU Jalandhar,Manufacturing Research Lab GNDEC,Ludhiana and DST GOI for financial support
文摘Fused deposition modeling(FDM) is one of the latest rapid prototyping techniques in which parts can be manufactured at a fast pace and are manufactured with a high accuracy. This research work is carried out to study the friction and wear behavior of parts made of newly developed Nylon6-Fe composite material by FDM. This work also involves the comparison of the friction and wear characteristics of the Nylon6-Fe composite with the existing acrylonitrile butadiene styrene(ABS) filament of the FDM machine. This Is carried out on the pin on disk setup by varying the load(5, 10, 15 and 20 N) and speed(200 and 300 r/min). It is concluded that the newly developed composite is highly wear resistant and can be used in industrial applications where wear resistance is of paramount importance. Morphology of the surface in contact with the Nylon6-Fe composite and ABS is also carried out.
文摘A new particle deposition model, namely partial deposition model, is developed in order to improve the accuracy of prediction to particle deposition. Concepts of critical velocity and critical angle are proposed and used to determine whether particles are deposited or not. The comparison of numerical results calculated by partial deposition model and existing deposition model shows that the deposition distribution obtained by partial deposition model is more reasonable. Based on the predicted deposition results, the change of total pressure loss coefficient with operating time and the distribution of pressure coefficients on blade surface after 500 hours are predicted by using partial deposition model.
基金The authors gratefully acknowledge the financial support by the Jiangsu Key R&D program(BE2019072).
文摘The paper discusses the mechanical and thermal performance manifested in natural nanorods attapulgite(ATP)reinforced Acrylonitrile butadiene styrene(ABS)nanocomposites in the process of fused deposition modeling(FDM).Molten extrusion technique was taken to manufacture the filaments of ABS/organic-attapulgite(OAT)nanocomposites with different mass fraction and the printing operation was made by one commercial FDM three-dimensional(3D)printer.Results indicate that the mechanical performance of these FDM 3D printed specimens are improved obviously via the introduction of OAT,and tensile strength of the ABS/OAT nanocomposites parts with only 2 wt%OAT addition is enhanced by 48.1%.At the same time,the addition OAT can reduce the linear expansion coefficient and creep flexibility,and improve the thermal stability and dimensional accuracy of these FDM 3D printed parts.
基金The result was obtained through the financial support of the Ministry of Education Malaysia under Grant Number RACER/2019/FKM-CARE/F00408This paper’s publication also funded by UTeM Incentive Jurnal Q00049/JURNAL/2020/FKM.
文摘Naturalfibre as a reinforcing agent has been widely used in many industrial applications.Nevertheless,several factors need to be considered,such as the size and weight percentage of thefibre used in binding.Using fused deposition modelling(FDM),this factor was investigated by varying the size of naturalfibre as the responding variable with afixed weight percentage of kenaffibre.The process of modifying the naturalfibre in terms of size might increase the dispersion of kenaffibre in the polymer matrix and increase the adhesion bonding between thefibre and matrix of composites,subsequently improving the interfacial bonding between these two phases.In this paper,the effect offibre size was evaluated by performing the mechanical test,Scanning Electron Micrograph(SEM)to observe the morphology of the composites,and also by surface analysis.The surface roughness was visualised using a 3D profilometer and thefigure was illustrated as colour shading in the image.The composite withfibre size≤100μm displayed better tensile andflexural strength,compared to other sizes.In conclusion,by reducing the size of thefibre,the composites could develop high strength performance for industrial applications.
基金The work presented in this study was orally presented at the first China–Vietnam symposium on precision manufacturing–CVPMS 2018,Industrial University of Ho Chi Minh City in Vietnam.
文摘In this study,we investigated warpage and corner lifting minimization for three-dimensional printed parts generated by macro-size fused deposition modeling(FDM).First,the reasons for warpage were theoretically elucidated.This approach revealed that the thermal deformation and differential volumetric shrinkage of the extruded molten plastic resulted in warpage of FDM parts.In addition,low adhesion between the deposited model and the heated or non-heated printing bed may intensify warpage further.As a next step,initial small-size and medium-size models were used to identify parameters to manage and minimize warpage in a way that would reduce material consumption and running time.Finally,a macro-size model was built to experimentally investigate and verify the technical solutions to minimize the warpage of FDM parts.In conclusion,an improved part with reduced warpage was efficiently produced after detailed consideration of thermal effects and adhesion force.Potential exists to widen the application scope of FDM technology in manufacturing for processes like thermoforming that involve mold core fabrication with heating.This technology,which has applications not only in mechanical engineering but also in related engineering fields,is convenient and could readily be applied to practical manufacturing industries.
基金Project (No. 50576088) supported by the National Natural Science Foundation of China
文摘The geometrical model of the filament during the fused deposition modeling (FDM) process was firstly proposed based on three different models, tractrix, parabola, and catenary. Comparing with the actual measured filament curves on the Stratasys 1600 FDM machine, it is indicated that the tractrix model had the best agreement with the actual measured curves. With the analytical simulation, the nozzle trajectories in the straight-line deposition road, circle road, and arbitrary continuous curve road were deduced, according to the traxtric based geometrical model of the filament.
文摘The urgent need to develop customized functional products only possible by 3D printing had realized when faced with the unavailability of medical devices like surgical instruments during the coronavirus-19 disease and the ondemand necessity to perform surgery during space missions.Biopolymers have recently been the most appropriate option for fabricating surgical instruments via 3D printing in terms of cheaper and faster processing.Among all 3D printing techniques,fused deposition modelling(FDM)is a low-cost and more rapid printing technique.This article proposes the fabrication of surgical instruments,namely,forceps and hemostat using the fused deposition modeling(FDM)process.Excellent mechanical properties are the only indicator to judge the quality of the functional parts.The mechanical properties of FDM-processed parts depend on various process parameters.These parameters are layer height,infill pattern,top/bottom pattern,number of top/bottom layers,infill density,flow,number of shells,printing temperature,build plate temperature,printing speed,and fan speed.Tensile strength and modulus of elasticity are chosen as evaluation indexes to ascertain the mechanical properties of polylactic acid(PLA)parts printed by FDM.The experiments have performed through Taguchi’s L27orthogonal array(OA).Variance analysis(ANOVA)ascertains the significance of the process parameters and their percent contributions to the evaluation indexes.Finally,as a multiobjective optimization technique,grey relational analysis(GRA)obtains an optimal set of FDM process parameters to fabricate the best parts with comprehensive mechanical properties.Scanning electron microscopy(SEM)examines the types of defects and strong bonding between rasters.The proposed research ensures the successful fabrication of functional surgical tools with substantial ultimate tensile strength(42.6 MPa)and modulus of elasticity(3274 MPa).
基金Mastura M.T.received financial support from the Ministry of Higher Education Malaysia(https://www.mohe.gov.my/en/services/research/mygrants)Universiti Teknikal Malaysia Melaka through the Fundamental Research Grant Scheme(FRGS/1/2020/FTKMP-CARE/F00456).
文摘The employment of natural fibres in fused deposition modeling has raised much attention from researchers in finding a suitable formulation for the natural fibre composite filaments.Moreover,selection of suitable natural fibres for fused deposition modeling should be performed before the development of the composites.It could not be performed without identifying selection criteria that comprehend both materials and fused deposition modeling process requirements.Therefore,in this study,integration of the Analytic Hierarchy Process(AHP)/Analytic Network Process(ANP)has been introduced in selecting the natural fibres based in different clusters of selection concurrently.The selection process has been performed based on the interdependency among the selection criteria.Pairwise comparison matrices are constructed based on AHP’s hierarchical model and super matrices are constructed based on the ANP’s network model.As a result,flax fibre has ranked at the top of the selection by scored 19.5%from the overall evaluation.Flax fibre has excellent material properties and been found in various natural fibre composite applications.Further investigation is needed to study the compatibility of this fibre to be reinforced with a thermoplastic polymer matrix to develop a resultant natural fibre composite filament for fused deposition modeling.
文摘FDM （fused deposition modeling） has become popular among Additive Manufacturing technologies due to its speed, geometric scalability, and low cost; however, the primitive nature of the FDM build surface fundamentally limits the utility of FDM in terms of reliability, autonomy, and material selection. Currently, FDM relies on adhesive forces between the first layer of a print and the build surface; depending on the materials involved, this adhesive bond may or may not be reliable. Thermal contraction between the build plate and build materials can break that bond, which causes warpage and delamination of the part from the build surface and subsequent failure of the part. Furthermore, with each print, the user must use tools or manual maneuvering to separate the printed part from the build surface as well as retexture or replace the used build surface. In this paper, we present a novel build platform that allows for a mechanical bond between the print and build surface by using dovetail-shaped features. The first layer of the print flows into the features and becomes mechanically captivated by the build platform. Once the print is completed, the platform is rolled or flexed open to release the part from the mechanical bond. This design not only lowers the risk of delamination during printing but also eliminates the need for a user to reset or replace the build surface between print jobs. The effectiveness of each geometry was determined by measuring the distance at the pinch point compared to the distance that the extrusion filled below the pinch point. The captivation ratio was measured to compare the different geometries tested and determine which direction of extrusion creates a better ratio.
基金Financial support was provided by the European Union-Next Generation EU-NRRP M4.C2-Investment 1.5 Establishing and Strengthening of Innovation Ecosystems for Sustainability(Rome Technopole)under Project ECS00000024.
文摘Integrating extrusion-based fused deposition modeling(FDM)with advancements in conductive thermoplastic materials is fostering innovation in the fabrication of sensors,electrodes,and printable electronics.This review presents an in-depth analysis of the advantages and disadvantages of FDM compared to other additive manufacturing(AM)techniques,focusing on its unique capacity to create functional components.Various materials,including host materials and conductive filaments,both commercial and custom-made,are examined for their suitability in conductive component fabrication.The impact of key process parameters,such as pre-printing settings,printing parameters(e.g.,layer thickness,infill density and pattern,print speed,extrusion width,raster angle and orientation,and bed temperature),and post-printing settings on the performance of conductive filaments is also discussed.The review highlights the working principles and applications of different types of sensors printed using FDM,including strain,pressure,temperature,and acceleration sensors,the fabrication of electrodes for physiological and electrochemical monitoring,showcasing the potential of FDM to integrate multifunctional sensing capabil-ities in a single build.Finally,the review explores the future prospects of FDM in sensor and electrode manufacturing,identifying key challenges that need to be overcome to further enhance the technology's potential in advanced applications.
基金supported by the project of the China Geological Survey(DD20221661).
文摘The black shales of Wufeng and Longmaxi Formation(Late Ordovician-Early Silurian period)in Sichuan Basin are the main strata for marine shale gas exploration,which have a yearly shale gas production of 228×10^(8)m^(3)and cumulative shale gas production of 919×10^(8)m^(3).According to the lithological and biological features,filling sequences,sedimentary structures and lab analysis,the authors divided the Wufeng/Guanyinqiao and Longmaxi Formations into shore,tidal flat,shoal,shallow water shelf and deep water shelf facies,and confirmed that a shallow water deposition between the two sets of shales.Although both Formations contain similar shales,their formation mechanisms differ.During the deposition of Wufeng shale,influenced by the Caledonian Movement,the Central Sichuan and Guizhou Uplifts led to the transformation of the Sichuan Basin into a back-bulge basin.Coinstantaneous volcanic activity provided significant nutrients,contributing to the deposition of Wufeng Formation black shales.In contrast,during the deposition of Longmaxi shale,collisions caused basement subsidence,melting glaciers raised sea levels,and renewed volcanic activity provided additional nutrients,leading to Longmaxi Formation black shale accumulation.Considering the basic sedimentary geology and shale gas characteristics,areas such as Suijiang-Leibo-Daguan,Luzhou-Zigong,Weirong-Yongchuan,and Nanchuan-Dingshan are identified as key prospects for future shale gas exploration in the Wufeng-Longmaxi Formations.
基金Supported by Jinchang City Level Science and Technology Plan Project(No.2023RC012).
文摘The lower member of Dalazi Formation is an important oil reservoir in the Songjiang Basin.Based on the research on its field-measured geological profiles,lithological combination characteristics and grain size distribution characteristics,combined with the analysis of the spatial distribution characteristics,sedimentary structural characteristics and hydrodynamic conditions of the sediments in this member,nine sedimentary microfacies of the fan delta plain subfacies,fan delta front subfacies and littoral-shallow lacustrine subfacies have been identified.The study reveals that lower member of Dalazi Formation in the research area follows a fan delta–shallow lacustrine depositional model in the steep slope zone of a rift lake basin.The sediments primarily originate from the Pre-Mesozoic strata in the steep southeastern and eastern margins.The basin center migrated from the early Xiaoshahe area to the Yangmucun–Shenglicun area,and the sedimentary system gradually transitioned from fan delta to littoral-shallow lacustrine facies.
