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Ritter T, McNiffe E, Higgins T, Sam-Daliri O, Flanagan T, Walls M, Ghabezi P, Finnegan W, Mitchell S, Harrison NM. Design and Modification of a Material Extrusion 3D Printer to Manufacture Functional Gradient PEEK Components. Polymers (Basel) 2023; 15:3825. [PMID: 37765679 PMCID: PMC10538106 DOI: 10.3390/polym15183825] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/23/2023] [Accepted: 08/27/2023] [Indexed: 09/29/2023] Open
Abstract
In recent years, the creative use of polymers has been expanded as the range of achievable material properties and options for manufacturing and post-processing continually grows. The main goal of this research was to design and develop a fully-functioning material extrusion additive manufacturing device with the capability to produce functionally graded high-temperature thermoplastic PEEK (polyether ether ketone) materials through the manipulation of microstructure during manufacturing. Five different strategies to control the chamber temperature and crystallinity were investigated, and concepts of thermal control were introduced to govern the crystallisation and cooling mechanics during the extrusion process. The interaction of individually deposited beads of material during the printing process was investigated using scanning electron microscopy to observe and quantify the porosity levels and interlayer bonding strength, which affect the quality of the final part. Functional testing of the printed parts was carried out to identify crystallinity, boundary layer adhesion, and mechanical behaviour. Furnace cooling and annealing were found to be the most effective methods, resulting in the highest crystallinity of the part. Finally, a functionally graded material cylindrical part was printed successfully, incorporating both low and high crystalline regions.
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Affiliation(s)
- Tobias Ritter
- School of Engineering, University of Galway, Galway, Ireland (W.F.); (S.M.); (N.M.H.)
- I-Form, the SFI Research Centre for Advanced Manufacturing, Ireland
| | - Eric McNiffe
- School of Engineering, University of Galway, Galway, Ireland (W.F.); (S.M.); (N.M.H.)
- I-Form, the SFI Research Centre for Advanced Manufacturing, Ireland
| | - Tom Higgins
- School of Engineering, University of Galway, Galway, Ireland (W.F.); (S.M.); (N.M.H.)
- I-Form, the SFI Research Centre for Advanced Manufacturing, Ireland
| | - Omid Sam-Daliri
- School of Engineering, University of Galway, Galway, Ireland (W.F.); (S.M.); (N.M.H.)
- I-Form, the SFI Research Centre for Advanced Manufacturing, Ireland
| | - Tomas Flanagan
- Éire Composites Teo, Údarás Industrial Estate, An Choill Rua, Inverin, Co., H91 Y923 Galway, Ireland
| | - Michael Walls
- CTL Tástáil Teo, Údarás Industrial Estate, An Choill Rua, Inverin, Co., H91 Y923 Galway, Ireland
| | - Pouyan Ghabezi
- School of Engineering, University of Galway, Galway, Ireland (W.F.); (S.M.); (N.M.H.)
- I-Form, the SFI Research Centre for Advanced Manufacturing, Ireland
- Construct Innovate & SFI MaREI Research Centre, University of Galway, Galway, Ireland
| | - William Finnegan
- School of Engineering, University of Galway, Galway, Ireland (W.F.); (S.M.); (N.M.H.)
- I-Form, the SFI Research Centre for Advanced Manufacturing, Ireland
- Construct Innovate & SFI MaREI Research Centre, University of Galway, Galway, Ireland
| | - Sinéad Mitchell
- School of Engineering, University of Galway, Galway, Ireland (W.F.); (S.M.); (N.M.H.)
- Ryan Institute for Environmental, Marine and Energy Research, University of Galway, Galway, Ireland
| | - Noel M. Harrison
- School of Engineering, University of Galway, Galway, Ireland (W.F.); (S.M.); (N.M.H.)
- I-Form, the SFI Research Centre for Advanced Manufacturing, Ireland
- Construct Innovate & SFI MaREI Research Centre, University of Galway, Galway, Ireland
- Ryan Institute for Environmental, Marine and Energy Research, University of Galway, Galway, Ireland
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2
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Bernagozzi G, Battegazzore D, Arrigo R, Frache A. Optimizing the Rheological and Thermal Behavior of Polypropylene-Based Composites for Material Extrusion Additive Manufacturing Processes. Polymers (Basel) 2023; 15:polym15102263. [PMID: 37242838 DOI: 10.3390/polym15102263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/09/2023] [Accepted: 05/10/2023] [Indexed: 05/28/2023] Open
Abstract
In this study, composites based on a heterophasic polypropylene (PP) copolymer containing different loadings of micro-sized (i.e., talc, calcium carbonate, and silica) and nano-sized (i.e., a nanoclay) fillers were formulated via melt compounding to obtain PP-based materials suitable for Material Extrusion (MEX) additive manufacturing processing. The assessment of the thermal properties and the rheological behavior of the produced materials allowed us to disclose the relationships between the influence of the embedded fillers and the fundamental characteristics of the materials affecting their MEX processability. In particular, composites containing 30 wt% of talc or calcium carbonate and 3 wt% of nanoclay showed the best combination of thermal and rheological properties and were selected for 3D printing processing. The evaluation of the morphology of the filaments and the 3D-printed samples demonstrated that the introduction of different fillers affects their surface quality as well as the adhesion between subsequently deposited layers. Finally, the tensile properties of 3D-printed specimens were assessed; the obtained results showed that modulable mechanical properties can be achieved depending on the type of the embedded filler, opening new perspectives towards the full exploitation of MEX processing in the production of printed parts endowed with desirable characteristics and functionalities.
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Affiliation(s)
- Giulia Bernagozzi
- Department of Applied Science and Technology, Politecnico di Torino, Viale Teresa Michel 5, 15121 Alessandria, Italy
| | - Daniele Battegazzore
- Department of Applied Science and Technology, Politecnico di Torino, Viale Teresa Michel 5, 15121 Alessandria, Italy
| | - Rossella Arrigo
- Department of Applied Science and Technology, Politecnico di Torino, Viale Teresa Michel 5, 15121 Alessandria, Italy
- Local INSTM Unit, 15121 Alessandria, Italy
| | - Alberto Frache
- Department of Applied Science and Technology, Politecnico di Torino, Viale Teresa Michel 5, 15121 Alessandria, Italy
- Local INSTM Unit, 15121 Alessandria, Italy
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3
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Austermann J, Kuscera R, Wipperfürth J, Hopmann C, Dahlmann R. Influence of material modification and fillers on the dimensional stability and warpage of polypropylene in screw‐extrusion‐based large area additive manufacturing. POLYM ENG SCI 2023. [DOI: 10.1002/pen.26309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Affiliation(s)
- Johannes Austermann
- Institute for Plastics Processing (IKV) in Industry and Craft RWTH Aachen University Seffenter Weg 201 Aachen 52074 Germany
| | - Renata Kuscera
- REHAU Industries SE & Co Coesfelder Straße 47 Velen 46342 Germany
| | - Jens Wipperfürth
- Institute for Plastics Processing (IKV) in Industry and Craft RWTH Aachen University Seffenter Weg 201 Aachen 52074 Germany
| | - Christian Hopmann
- Institute for Plastics Processing (IKV) in Industry and Craft RWTH Aachen University Seffenter Weg 201 Aachen 52074 Germany
| | - Rainer Dahlmann
- Institute for Plastics Processing (IKV) in Industry and Craft RWTH Aachen University Seffenter Weg 201 Aachen 52074 Germany
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4
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Differential Scanning Calorimetry Material Studies: Benzil Melting Point Method for Eliminating the Thermal History of DSC. J CHEM-NY 2022. [DOI: 10.1155/2022/3423429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
How to eliminate the thermal history present in differential scanning calorimetry, this question has been widely concerned. Benzil has a serious thermal history that is not well eliminated by conventional thermal history methods. Herein, using benzil as a target, we developed a freeze-gradient temperature rate heating up method to eliminate the thermal history of DSC. Compared with the conventional method, this method avoids the introduction of new thermal histories by new crystalline forms that may appear during the cooling crystallization process. The results show that the peak shape of the melting peak is sharper and the peak emergence position is closer to the theoretical melting point after the elimination of the thermal history by the freeze-gradient heating up method. Based on this method, we optimized other factors to establish a complete method for the determination of melting point by DSC, analyzed the uncertainty of the method, and obtained an extended uncertainty of 0.19°C for DSC in this method. The validation results show that the p-nitrotoluene of the melting point reference substance was 52.64°C, which is within its reference value of (52.53 ± 0.20) °C, showing that this method is reliable. This study provides a reference for other thermal analysis methods to eliminate thermal history.
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5
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Influence of Ambient Temperature on Part Distortion: A Simulation Study on Amorphous and Semi-Crystalline Polymer. Polymers (Basel) 2022; 14:polym14050879. [PMID: 35267702 PMCID: PMC8912715 DOI: 10.3390/polym14050879] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/27/2022] [Accepted: 02/10/2022] [Indexed: 12/30/2022] Open
Abstract
Semi-crystalline polymers develop higher amounts of residual stress and part distortion (warpage) compared to amorphous polymers due to their crystalline nature. Additionally, the FDM processing parameters such as ambient temperature play an important role in the resulting residual stresses and part distortion of the printed part. Hence, in this study, the effect of ambient temperature on the in-built residual stresses and warpage of amorphous acrylonitrile-butadiene-styrene (ABS) and semi-crystalline polypropylene (PP) polymers was investigated. From the results, it was observed that increasing the ambient temperature from 50 °C to 75 °C and further to 120 °C resulted in 0.22-KPa and 0.37-KPa decreases in residual stress of ABS, but no significant change in the amount of warpage. For PP, increasing ambient temperature from 50 °C to 75 °C led to a more considerable decrease in residual stress (0.5 MPa) and about 3% increase in warpage. Further increasing to 120 °C resulted in a noticeable 2 MPa decrease in residual stress and a 3.4% increase in warpage. Reduction in residual stress in both ABS and PP as a result of increasing ambient temperature was due to the reduced thermal gradients. The enhanced warpage in PP with increase in ambient temperature, despite the reduction in residual stress, was ascribed to crystallization and shrinkage.
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Dimonie D, Mathe S, Iftime MM, Ionita D, Trusca R, Iftimie S. Modulation of the PLLA Morphology through Racemic Nucleation to Reach Functional Properties Required by 3D Printed Durable Applications. MATERIALS (BASEL, SWITZERLAND) 2021; 14:6650. [PMID: 34772174 PMCID: PMC8588124 DOI: 10.3390/ma14216650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/29/2021] [Accepted: 10/31/2021] [Indexed: 11/16/2022]
Abstract
This paper presents an alternative for enhancing the durability of poly (L-lactide) (PLLA) by racemic nucleation following stereo-complexation with a selected poly (D-lactide) (PLDA). The compounds are obtained by melt blending of a PLLA grade, previously designed for 3D printing but with a low heat deflection temperature and impact resistance, with grades of PLDA differing in their molecular weight (Mw), D-lactide content (DS) and concentration. Our method considered how to reveal the racemic nucleation caused by stereo-complexation and its influence on functional properties. The FTIR study we performed showed that, depending on Mw, DS and concentration of the stereo-complexer (PDLA) used, bigger or smaller spectral changes can occur. The stereo-complexation was confirmed by the DSC analysis and, for the selected compound, by the POM, SEM, AFM microscopies, functional property and shapeability as 3D printing filaments. All the obtained results sustain the idea that, if a PLLA with Mw of 4.5 × 104 g·mol-1 is modified with PDLA with a medium Mw of 11.6 × 104 g·mol-1, medium DS of 4% and 1% concentration, a racemic nucleation is possible. It produces a racemic polylactic acid (PDLLA) with improved durability and good shapeability as 3D printing filaments. These results are explicable if the dependence of the intermolecular interactions appears between the PLLA and stereo-complexer PDLA. To enlarge the durable applicability of racemic polylactic acid (PDLLA), future research should identify other parameters controling the PLA stereo-complexing as the intensifying the mobility of the macromolecules, the finding of the optimal recemic cristalization window.
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Affiliation(s)
- Doina Dimonie
- National Institute for Research and Development in Chemistry and Petrochemistry, 202 Splaiul Independentei, 060021 Bucharest, Romania;
| | - Silvia Mathe
- Doctoral School “Applied Chemistry and Materials Science”, Politehnica University of Bucharest, 1-7 Gheorghe Polizu, 011061 Bucharest, Romania
| | - Manuela Maria Iftime
- “Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi, Romania; (M.M.I.); (D.I.)
| | - Daniela Ionita
- “Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi, Romania; (M.M.I.); (D.I.)
| | - Roxana Trusca
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Politehnica University of Bucharest, 1-7 Gheorghe Polizu, 011061 Bucharest, Romania;
| | - Sorina Iftimie
- Department of Electricity and Magnetism, Solid-State Physics, and Biophysics, Faculty of Physics, University of Bucharest, 405 Atomistilor, 077125 Magurele, Romania;
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7
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Vaes D, Coppens M, Goderis B, Zoetelief W, Van Puyvelde P. The Extent of Interlayer Bond Strength during Fused Filament Fabrication of Nylon Copolymers: An Interplay between Thermal History and Crystalline Morphology. Polymers (Basel) 2021; 13:polym13162677. [PMID: 34451217 PMCID: PMC8401508 DOI: 10.3390/polym13162677] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 11/16/2022] Open
Abstract
One of the main drawbacks of Fused Filament Fabrication is the often-inadequate mechanical performance of printed parts due to a lack of sufficient interlayer bonding between successively deposited layers. The phenomenon of interlayer bonding becomes especially complex for semi-crystalline polymers, as, besides the extremely non-isothermal temperature history experienced by the extruded layers, the ongoing crystallization process will greatly complicate its analysis. This work attempts to elucidate a possible relation between the degree of crystallinity attained during printing by mimicking the experienced thermal history with Fast Scanning Chip Calorimetry, the extent of interlayer bonding by performing trouser tear fracture tests on printed specimens, and the resulting crystalline morphology at the weld interface through visualization with polarized light microscopy. Different printing conditions are defined, which all vary in terms of processing parameters or feedstock molecular weight. The concept of an equivalent isothermal weld time is utilized to validate whether an amorphous healing theory is capable of explaining the observed trends in weld strength. Interlayer bond strength was found to be positively impacted by an increased liquefier temperature and reduced feedstock molecular weight as predicted by the weld time. An increase in liquefier temperature of 40 °C brings about a tear energy value that is three to four times higher. The print speed was found to have a negligible effect. An elevated build plate temperature will lead to an increased degree of crystallinity, generally resulting in about a 1.5 times larger crystalline fraction compared to when printing occurs at a lower build plate temperature, as well as larger spherulites attained during printing, as it allows crystallization to occur at higher temperatures. Due to slower crystal growth, a lower tie chain density in the amorphous interlamellar regions is believed to be created, which will negatively impact interlayer bond strength.
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Affiliation(s)
- Dries Vaes
- Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200J Box 2424, 3001 Leuven, Belgium; (D.V.); (M.C.)
| | - Margot Coppens
- Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200J Box 2424, 3001 Leuven, Belgium; (D.V.); (M.C.)
| | - Bart Goderis
- Department of Chemistry, KU Leuven, Celestijnenlaan 200F Box 2404, 3001 Leuven, Belgium;
| | - Wim Zoetelief
- DSM Additive Manufacturing, Urmonderbaan 22, 6167 RD Geleen, The Netherlands;
| | - Peter Van Puyvelde
- Department of Chemical Engineering, KU Leuven, Celestijnenlaan 200J Box 2424, 3001 Leuven, Belgium; (D.V.); (M.C.)
- Correspondence:
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8
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9
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Fused Filament Fabrication of Polymers and Continuous Fiber-Reinforced Polymer Composites: Advances in Structure Optimization and Health Monitoring. Polymers (Basel) 2021; 13:polym13050789. [PMID: 33806621 PMCID: PMC7961789 DOI: 10.3390/polym13050789] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 02/26/2021] [Accepted: 02/26/2021] [Indexed: 02/07/2023] Open
Abstract
3D printed neat thermoplastic polymers (TPs) and continuous fiber-reinforced thermoplastic composites (CFRTPCs) by fused filament fabrication (FFF) are becoming attractive materials for numerous applications. However, the structure of these materials exhibits interfaces at different scales, engendering non-optimal mechanical properties. The first part of the review presents a description of these interfaces and highlights the different strategies to improve interfacial bonding. The actual knowledge on the structural aspects of the thermoplastic matrix is also summarized in this contribution with a focus on crystallization and orientation. The research to be tackled to further improve the structural properties of the 3D printed materials is identified. The second part of the review provides an overview of structural health monitoring technologies relying on the use of fiber Bragg grating sensors, strain gauge sensors and self-sensing. After a brief discussion on these three technologies, the needed research to further stimulate the development of FFF is identified. Finally, in the third part of this contribution the technology landscape of FFF processes for CFRTPCs is provided, including the future trends.
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10
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Bayart M, Charlon S, Soulestin J. Fused filament fabrication of scaffolds for tissue engineering; how realistic is shape-memory? A review. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123440] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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11
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Synergistic effect of plasticizer and nucleating agent on crystallization behavior of polylactide during fused filament fabrication. POLYMER 2021. [DOI: 10.1016/j.polymer.2021.123426] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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12
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Vidakis N, Petousis M, Tzounis L, Maniadi A, Velidakis E, Mountakis N, Kechagias JD. Sustainable Additive Manufacturing: Mechanical Response of Polyamide 12 over Multiple Recycling Processes. MATERIALS 2021; 14:ma14020466. [PMID: 33478083 PMCID: PMC7835918 DOI: 10.3390/ma14020466] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 01/12/2021] [Accepted: 01/15/2021] [Indexed: 01/10/2023]
Abstract
Plastic waste reduction and recycling through circular use has been critical nowadays, since there is an increasing demand for the production of plastic components based on different polymeric matrices in various applications. The most commonly used recycling procedure, especially for thermoplastic materials, is based on thermomechanical process protocols that could significantly alter the polymers’ macromolecular structure and physicochemical properties. The study at hand focuses on recycling of polyamide 12 (PA12) filament, through extrusion melting over multiple recycling courses, giving insight for its effect on the mechanical and thermal properties of Fused Filament Fabrication (FFF) manufactured specimens throughout the recycling courses. Three-dimensional (3D) FFF printed specimens were produced from virgin as well as recycled PA12 filament, while they have been experimentally tested further for their tensile, flexural, impact and micro-hardness mechanical properties. A thorough thermal and morphological analysis was also performed on all the 3D printed samples. The results of this study demonstrate that PA12 can be successfully recycled for a certain number of courses and could be utilized in 3D printing, while exhibiting improved mechanical properties when compared to virgin material for a certain number of recycling repetitions. From this work, it can be deduced that PA12 can be a viable option for circular use and 3D printing, offering an overall positive impact on recycling, while realizing 3D printed components using recycled filaments with enhanced mechanical and thermal stability.
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Affiliation(s)
- Nectarios Vidakis
- Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Crete, Greece; (N.V.); (E.V.); (N.M.)
| | - Markos Petousis
- Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Crete, Greece; (N.V.); (E.V.); (N.M.)
- Correspondence: ; Tel.: +30-2810-37-9227
| | - Lazaros Tzounis
- Department of Materials Science and Engineering, University of Ioannina, 45110 Ioannina, Greece;
| | - Athena Maniadi
- Department of Materials Science and Technology, University of Crete, 70013 Heraklion, Crete, Greece;
| | - Emmanouil Velidakis
- Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Crete, Greece; (N.V.); (E.V.); (N.M.)
| | - Nikolaos Mountakis
- Mechanical Engineering Department, Hellenic Mediterranean University, 71410 Heraklion, Crete, Greece; (N.V.); (E.V.); (N.M.)
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Gaweł A, Kuciel S. The Study of Physico-Mechanical Properties of Polylactide Composites with Different Level of Infill Produced by the FDM Method. Polymers (Basel) 2020; 12:E3056. [PMID: 33419345 PMCID: PMC7767082 DOI: 10.3390/polym12123056] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/15/2020] [Accepted: 12/17/2020] [Indexed: 11/16/2022] Open
Abstract
The aim of this study was to evaluate the changes in physical-mechanical properties of the samples manufactured by 3D printing technology with the addition of varying degrees of polylactide (PLA) infill (50, 70, 85 and 100%). Half of the samples were soaked in physiological saline. The material used for the study was neat PLA, which was examined in terms of hydrolytic degradation, crystallization, mechanical strength, variability of properties at elevated temperatures, and dissipation of mechanical energy depending on the performed treatment. A significant impact of the amount of infill on changeable mechanical properties, such as hydrolytic degradation and crystallization was observed. The FDM printing method allows for waste-free production of light weight unit products with constant specyfic strength.
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Affiliation(s)
| | - Stanisław Kuciel
- Faculty of Materials Engineering and Physics, Institute of Materials Engineering, Tadeusz Kosciuszko Cracow University of Technology, Al. Jana Pawła II 37, 31-864 Cracow, Poland;
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14
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Fused Deposition Modeling of Polyamides: Crystallization and Weld Formation. Polymers (Basel) 2020; 12:polym12122980. [PMID: 33327516 PMCID: PMC7764950 DOI: 10.3390/polym12122980] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 11/16/2022] Open
Abstract
International newspapers and experts have called 3D printing the industrial revolution of this century. Among all its available variants, the fused deposition modeling (FDM) technique is of greater interest since its application is possible using simple desktop printers. FDM is a complex process, characterized by a large number of parameters that influence the quality and final properties of the product. In particular, in the case of semicrystalline polymers, which afford better mechanical properties than amorphous ones, it is necessary to understand the crystallization kinetics as the processing conditions vary, in order to be able to develop models that allow having a better control over the process and consequently on the final properties of the material. In this work it was proposed to study the crystallization kinetics of two different polyamides used for FDM 3D printing and to link it to the microstructure and properties obtained during FDM. The kinetics are studied both in isothermal and fast cooling conditions, thanks to a home-built device which allows mimicking the quenching experienced during filament deposition. The temperature history of a single filament is then determined by mean of a micro-thermocouple and the final crystallinity of the sample printed in a variety of conditions is assessed by differential scanning calorimetry. It is found that the applied processing conditions always allowed for the achievement of the maximum crystallinity, although in one condition the polyamide mesomorphic phase possibly develops. Despite the degree of crystallinity is not a strong function of printing variables, the weld strength of adjacent layers shows remarkable variations. In particular, a decrease of its value with printing speed is observed, linked to the probable development of molecular anisotropy under the more extreme printing conditions.
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15
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Terekhina S, Tarasova T, Egorov S, Skornyakov I, Guillaumat L, Hattali M. The effect of build orientation on both flexural quasi-static and fatigue behaviours of filament deposited PA6 polymer. INTERNATIONAL JOURNAL OF FATIGUE 2020; 140:105825. [PMID: 32834205 PMCID: PMC7357525 DOI: 10.1016/j.ijfatigue.2020.105825] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 07/06/2020] [Accepted: 07/08/2020] [Indexed: 06/09/2023]
Abstract
The present paper aims to study the effect of manufacturing build orientation on both flexural quasi-static and fatigue behaviours of semi-crystalline polyamide 6 obtained by Fused Filament Fabrication (FFF), by considering the porosity and surface roughness. The glass transition temperature, melting temperature, and crystallinity degree were measured complementary to understand better the process. Fatigue analysis is here fully described in visco-elastic domain of material. The results highlight that the XZ build orientation is better than the XY one and suggest that porosity plays an important role. The obtained results are also compared with conventional techniques given by the literature review.
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Affiliation(s)
- S. Terekhina
- Arts et Métiers ParisTech, Campus Angers, Laboratory LAMPA, 2 Bd du Ronceray, 49035 Angers Cedex 1, France
| | - T. Tarasova
- Moscow State University of Technology “STANKIN”, 3-A Vadkovskiy Pereulok, 127055 Moscow, Russia
| | - S. Egorov
- Moscow State University of Technology “STANKIN”, 3-A Vadkovskiy Pereulok, 127055 Moscow, Russia
| | - I. Skornyakov
- Moscow State University of Technology “STANKIN”, 3-A Vadkovskiy Pereulok, 127055 Moscow, Russia
| | - L. Guillaumat
- Arts et Métiers ParisTech, Campus Angers, Laboratory LAMPA, 2 Bd du Ronceray, 49035 Angers Cedex 1, France
| | - M.L. Hattali
- Université Paris-Saclay, CNRS, FAST, 91405 Orsay, France
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16
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Srinivas V, van Hooy-Corstjens CS, Rastogi S, Harings JA. Promotion of molecular diffusion and/or crystallization in fused deposition modeled poly(lactide) welds. POLYMER 2020. [DOI: 10.1016/j.polymer.2020.122637] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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17
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Synchrotron X-ray Scattering Analysis of Nylon-12 Crystallisation Variation Depending on 3D Printing Conditions. Polymers (Basel) 2020; 12:polym12051169. [PMID: 32443677 PMCID: PMC7285354 DOI: 10.3390/polym12051169] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/13/2020] [Accepted: 05/15/2020] [Indexed: 11/17/2022] Open
Abstract
Nylon-12 is an important structural polymer in wide use in the form of fibres and bulk structures. Fused filament fabrication (FFF) is an extrusion-based additive manufacturing (AM) method for rapid prototyping and final product manufacturing of thermoplastic polymer objects. The resultant microstructure of FFF-produced samples is strongly affected by the cooling rates and thermal gradients experienced across the part. The crystallisation behaviour during cooling and solidification influences the micro- and nano-structure, and deserves detailed investigation. A commercial Nylon-12 filament and FFF-produced Nylon-12 parts were studied by differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) to examine the effect of cooling rates under non-isothermal crystallisation conditions on the microstructure and properties. Slower cooling rates caused more perfect crystallite formation, as well as alteration to the thermal properties.
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