3D Printing Composites

A special issue of Journal of Composites Science (ISSN 2504-477X). This special issue belongs to the section "Composites Manufacturing and Processing".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 47594

Special Issue Editor

Center for Composite Materials, Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, USA
Interests: additive manufacturing; textile-based functional device; fiber composite; energy
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Additive manufacturing (AM) or 3D printing, which has potential benefits for automation, low cost, rapid prototyping, and customizability, can greatly outperform conventional polymer and composite manufacturing technologies, which suffer from time-consuming and labor-intensive problems during operation. Recent novel additive manufacturing technologies and rapidly developed polymer materials/chemistry have emphasized their combinations for constructing complicated architectures and realizing structurally and functionally customized designs, offering a great opportunity for structural and functional applications that transcend current manufacturing and outperform existing material process–property–structure relationships.

Since the origin of AM in the 1980s, there has been a rapid development with increasing interest in the development and expansion of additive manufacturing technologies for polymers and their composites. Additive manufacturing has been considered one of the transformative technologies for manufacturing polymers and composites, not only in rapid prototyping but also in the potential benefits in computerization, high efficiency, resolution, and customizability that go beyond existing manufacturing/processing technologies to trigger imagination and possibility in polymer applications (e.g., responsive 4D printing). Therefore, this Special Issue aims to highlight the additive manufacturing of polymers and composites, including polymer materials discovery and development, polymer and composite manufacturing strategies and modifications, composite architectures and constructions, mechanical enhancement of reinforced polymer composites, functional-driven constituent composition–structure relationships, and polymer and composite functional design and applications. This Special Issue will be a collection of peer-reviewed contributions that present original breakthrough research, comprehensive reviews, perspectives, or highlights to advance the frontier of 3D printing in polymers and composites.

Contributed articles are sought in the following, but not limited to, areas:

  • Advances in the additive manufacturing of polymers and composites;
  • Advances in additive manufacturing techniques;
  • Additive manufacturing in structural applications (e.g., lightweight and energy absorbing);
  • Additive manufacturing in functional applications (e.g., bio-applications, energy, environment, electronics, medical models and devices, and robotics);
  • New materials, new techniques, and emerging applications in polymer and composite additive manufacturing.

Dr. Kun Fu
Guest Editor

Manuscript Submission Information

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Keywords

  • Composites
  • 3D printing
  • Additive manufacturing
  • Functional composites

Published Papers (20 papers)

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18 pages, 4068 KiB  
Article
Post-Process Considerations for Photopolymer 3D-Printed Injection Moulded Insert Tooling Applications
by Gavin Keane, Andrew V. Healy and Declan M. Devine
J. Compos. Sci. 2024, 8(4), 151; https://doi.org/10.3390/jcs8040151 - 17 Apr 2024
Viewed by 329
Abstract
Injection moulding (IM) is a manufacturing technique used to produce intricately detailed plastic components with various surface finishes, enabling the production of high-tolerance functional parts at scale. Conversely, stereolithography (SLA) three-dimensional (3D) printing offers an alternative method for fabricating moulds with shorter lead [...] Read more.
Injection moulding (IM) is a manufacturing technique used to produce intricately detailed plastic components with various surface finishes, enabling the production of high-tolerance functional parts at scale. Conversely, stereolithography (SLA) three-dimensional (3D) printing offers an alternative method for fabricating moulds with shorter lead times and reduced costs compared to conventional manufacturing. However, fabrication in a layer-by-layer fashion results in anisotropic properties and noticeable layer lines, known as the stair-step effect. This study investigates post-processing techniques for plaques with contrasting stair-step effects fabricated from commercially available SLA high-temperature resin, aiming to assess their suitability for IM applications. The results reveal that annealing significantly enhances part hardness and heat deflection temperature (HDT), albeit with a trade-off involving reduced flexural strength. Experimental findings indicate that the optimal stage for abrasive surface treatment is after UV curing and before annealing. Plaques exhibiting contrasting stair-step effects are characterized and evaluated for weight loss, dimensional accuracy, and surface roughness. The results demonstrate that abrasive blasting effectively removes the stair-step effect without compromising geometry while achieving polished surface finishes with roughness average (RA) values of 0.1 μm through sanding. Overall, a combination of abrasive blasting and sanding proves capable of precisely defining surface roughness without significant geometry loss, offering a viable approach to achieving traditional IM finishes suitable for both functional and aesthetic purposes. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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14 pages, 9254 KiB  
Article
Influence of SiC Doping on the Mechanical, Electrical, and Optical Properties of 3D-Printed PLA
by Stefania Skorda, Achilleas Bardakas, Apostolos Segkos, Nikoleta Chouchoumi, Emmanouel Hourdakis, George Vekinis and Christos Tsamis
J. Compos. Sci. 2024, 8(3), 79; https://doi.org/10.3390/jcs8030079 - 22 Feb 2024
Viewed by 1210
Abstract
Additive manufacturing, also known as 3D printing or digital fabrication technology, is emerging as a fast-expanding technology for the fabrication of prototypes and products in a variety of applications. This is mainly due to the advantages of 3D printing including the ease of [...] Read more.
Additive manufacturing, also known as 3D printing or digital fabrication technology, is emerging as a fast-expanding technology for the fabrication of prototypes and products in a variety of applications. This is mainly due to the advantages of 3D printing including the ease of manufacturing, the use of reduced material quantities minimizing material waste, low-cost mass production as well as energy efficiency. Polylactic acid (PLA) is a natural thermoplastic polyester that is produced from renewable resources and is routinely used to produce 3D-printed structures. One important feature that makes PLA appealing is that its properties can be modulated by the inclusion of nano or microfillers. This is of special importance for 3D-printed triboelectric nanogenerators since it can enhance the performance of the devices. In this work we investigate the influence of SiC micron-sized particles on the mechanical, electrical, and optical properties of a PLA-SiC composite for potential application in triboelectric energy harvesting. Our result show that the ultimate tensile strength of the pure PLA and 1%-doped PLA decreases with the number of fatigue cycles but increases by about 10% when SiC doping increases to 2% and 3%, while the strain at max load was about 3% independent of doping and the effective hardness was increased reaching a plateau at about 2 wt% SiC, about 40% above the value for pure PLA. Our results show that the mechanical properties of PLA can be enhanced by the inclusion of SiC, depending on the concentration of SiC. In addition, the same behavior is observed for the dielectric constant of the composite material increases as the SiC concentration increases, while the optical properties of the resulting composite are strongly dependent on the concentration of SiC. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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12 pages, 14444 KiB  
Article
3D Printed and Embedded Strain Sensors in Structural Composites for Loading Monitoring and Damage Diagnostics
by Dongfang Zhao, Xingyu Liu, Jacob Meves, Christopher Billings and Yingtao Liu
J. Compos. Sci. 2023, 7(10), 437; https://doi.org/10.3390/jcs7100437 - 14 Oct 2023
Viewed by 1561
Abstract
The development of novel embedded sensors for structural health monitoring (SHM) is crucial to provide real-time assessments of composite structures, ensuring safety, and prolonging their service life. Early damage diagnostics through advanced sensors can lead to timely maintenance, reducing costs and preventing potential [...] Read more.
The development of novel embedded sensors for structural health monitoring (SHM) is crucial to provide real-time assessments of composite structures, ensuring safety, and prolonging their service life. Early damage diagnostics through advanced sensors can lead to timely maintenance, reducing costs and preventing potential catastrophic failures. This paper presents the synthesis, 3D printing, and characterization of novel embedded strain sensors using multi-walled carbon nanotube (MWCNT) -enhanced nanocomposites in fiberglass reinforced composites for potential damage diagnostics and SHM applications. MWCNTs are dispersed within structural epoxy for the additive manufacturing of nanocomposites with piezoresistive sensing capability. The 3D-printed nanocomposite sensors are embedded in fiberglass-reinforced composite laminates. The piezoresistive sensing capabilities of the 3D-printed sensors within composites are characterized by applying different levels of maximum loads and load rates under three-point bending loads. Additionally, the long-term reliability of the developed strain sensors is evaluated up to 1000 cycles. The recorded piezoresistive sensing signals show high sensitivity for the externally applied bending loads with advanced gauge factor up to 100, resulting in potential load sensing capability for in-situ damage diagnostics and real-time SHM for structural composites. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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21 pages, 5396 KiB  
Article
Solving Some Graph Problems in Composite 3D Printing Using Spreadsheet Modeling
by Larysa Hlinenko, Volodymyr Fast, Yevheniia Yakovenko, Roman Trach, Tomasz Wierzbicki, Sylwia Szymanek, Aleksandra Leśniewska, Yuriy Daynovskyy, Vasyl Rys and Eugeniusz Koda
J. Compos. Sci. 2023, 7(7), 299; https://doi.org/10.3390/jcs7070299 - 20 Jul 2023
Viewed by 915
Abstract
The use of composite materials in additive manufacturing has significant potential and prospects for development. However, the 3D printing of composite materials also has some challenges, such as tool path planning and optimization, material distribution and planning, optimization of printing parameters, and others. [...] Read more.
The use of composite materials in additive manufacturing has significant potential and prospects for development. However, the 3D printing of composite materials also has some challenges, such as tool path planning and optimization, material distribution and planning, optimization of printing parameters, and others. Graph theory may be suitable for solving some of them. Many practical problems can be modeled as problems of identifying subsets of graph vertices or edges with certain extremal properties. Such problems belong to the category of graph extremal problems. Some of these problems can be represented as integer linear programming problems, for which, in order to solve, modifications of simplex method can be used. These methods are supported by MS Excel Solver add-in, which suggests the possibility of solving these problems effectively with its help. The task of implementing procedures for solving such problems by means of standard engineering software seems to be possible. This paper aims to develop efficient spreadsheet models of some extremal problems for graphs of higher strength in order to prove the feasibility and to unify the procedures of solving such problems via the MS Excel Solver add-in. Several spreadsheet models based on the graph representation by its expanded incidence matrix, while specifying a vector of unknowns as the vector of binary variables associated with vertices or edges of the sought parts of the graph, have been developed and proven to be efficient for solving such problems by simplex method via the MS Excel Solver add-in. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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17 pages, 5311 KiB  
Article
Carbon-Fiber- and Nanodiamond-Reinforced PLA Hierarchical 3D-Printed Core Sandwich Structures
by Michel Theodor Mansour, Konstantinos Tsongas and Dimitrios Tzetzis
J. Compos. Sci. 2023, 7(7), 285; https://doi.org/10.3390/jcs7070285 - 12 Jul 2023
Cited by 3 | Viewed by 1136
Abstract
The aim of the present paper is to investigate the mechanical behavior of FFF 3D-printed specimens of polylactic acid (PLA), PLA reinforced with nanodiamonds (PLA/uDiamond) and PLA reinforced with carbon fibers (PLA/CF) under various experimental tests such as compressive and cyclic compressive tests, [...] Read more.
The aim of the present paper is to investigate the mechanical behavior of FFF 3D-printed specimens of polylactic acid (PLA), PLA reinforced with nanodiamonds (PLA/uDiamond) and PLA reinforced with carbon fibers (PLA/CF) under various experimental tests such as compressive and cyclic compressive tests, nanoindentation tests, as well as scanning electron microscopy tests (SEM). Furthermore, the current work aims to design and fabricate hierarchical honeycombs of the zeroth, first and second order using materials under investigation, and perform examination tests of their dynamic behavior. The mechanical behavior of hierarchical sandwich structures was determined by conducting experimental bending tests along with finite element analysis (FEA) simulations. The results reveal that the incorporation of nanodiamonds into the PLA matrix enhanced the elastic modulus, strength and hardness of the 3D-printed specimens. In addition, the second order of the PLA/uD hierarchical sandwich structure presented increased strength, elastic and flexural modulus in comparison with the zeroth and first hierarchies. Regarding the dynamic behavior, the second order of the PLA/uD honeycomb structure revealed the biggest increase in stiffness as compared to PLA nanocomposite filaments. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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21 pages, 3951 KiB  
Article
Investigation on Mechanical and Thermal Properties of 3D-Printed Polyamide 6, Graphene Oxide and Glass-Fibre-Reinforced Composites under Dry, Wet and High Temperature Conditions
by Mariah Ichakpa, Matthew Goodyear, Jake Duthie, Matthew Duthie, Ryan Wisely, Allan MacPherson, John Keyte, Ketan Pancholi and James Njuguna
J. Compos. Sci. 2023, 7(6), 227; https://doi.org/10.3390/jcs7060227 - 03 Jun 2023
Cited by 3 | Viewed by 1341
Abstract
This study is focused on 3D printing of polyamide 6 (PA6), PA6/graphene oxide (PA6/GO) and PA6/glass-fibre-reinforced (PA6/GF) composites. The effect of graphene oxide and glass-fibre reinforcement on 3D-printed PA6 is explored for improvement of the interfacial bond and interlaminar strength in ambient, wet [...] Read more.
This study is focused on 3D printing of polyamide 6 (PA6), PA6/graphene oxide (PA6/GO) and PA6/glass-fibre-reinforced (PA6/GF) composites. The effect of graphene oxide and glass-fibre reinforcement on 3D-printed PA6 is explored for improvement of the interfacial bond and interlaminar strength in ambient, wet and high temperature conditions relating to electric car battery box requirements. The influence of environmental conditions and process parameters on the 3D-printed polymer composites quality is also examined. Commercial PA6 filament was modified with GO to investigate the thermal and mechanical properties. The modified composites were melt-compounded using a twin-feed extruder to produce an improved 3D-printing filament. The improved filaments were then used to 3D-print test samples for tensile and compression mechanical testing using universal testing machines and thermal characterisation was performed following condition treatment in high temperature and water for correlation to dry/ambient samples. The study results show the studied materials were mostly suitable in dry/ambient conditions. PA6/GF samples demonstrated the highest strength of all three samples in ambient and high-temperature conditions, but the least strength in wet conditions due to osmotic pressure at the fibre/matrix interface that led to fibre breakage. The introduction of 0.1% GO improved the tensile strength by 33%, 11% and 23% in dry/ambient, dry/high temperature and wet/ambient conditions, respectively. The wet PA6/GO samples demonstrated the least strength in comparison to the ambient and high-temperature conditions. Notwithstanding this, PA6/GO exhibited the highest tensile strength in the wet condition, making it the most suitable for a high-strength, water-exposed engineering application. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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14 pages, 3672 KiB  
Article
High-Pressure FDM 3D Printing in Nitrogen [Inert Gas] and Improved Mechanical Performance of Printed Components
by Yousuf Pasha Shaik, Jens Schuster and Naresh Kumar Naidu
J. Compos. Sci. 2023, 7(4), 153; https://doi.org/10.3390/jcs7040153 - 10 Apr 2023
Viewed by 1945
Abstract
Fundamentally, the mechanical characteristics of 3D-printed polymeric objects are determined by their fabrication circumstances. In contrast to traditional polymer processing processes, additive manufacturing requires no pressure during layer consolidation. This study looks at how a high-pressure autoclave chamber without oxygen affects layer consolidation [...] Read more.
Fundamentally, the mechanical characteristics of 3D-printed polymeric objects are determined by their fabrication circumstances. In contrast to traditional polymer processing processes, additive manufacturing requires no pressure during layer consolidation. This study looks at how a high-pressure autoclave chamber without oxygen affects layer consolidation throughout the fused deposition modelling process, as well as the mechanical qualities of the products. To attain high strength qualities for 3D-printed components such as injection-molded specimens, an experimental setup consisting of a 3D printer incorporated within a bespoke autoclave was designed. The autoclave can withstand pressures of up to 135 bar and temperatures of up to 185 °C. PLA 3D printing was carried out in the autoclave at two different pressures in compressed air and nitrogen atmospheres: 0 bar and 5 bar. Furthermore, injection molding was done using the same PLA material. Tensile, flexural, and Charpy tests were carried out on samples that were 3D printed and injection molded. In nitrogen, oxidation of the environment was prevented by autoclave preheating before printing, and autoclave pressure during printing considerably promotes layer consolidation. This imprinted mechanical strength on the 3D-printed items, which are virtually as strong as injection-molded components. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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17 pages, 9150 KiB  
Article
Engineering Ligament Scaffolds Based on PLA/Graphite Nanoplatelet Composites by 3D Printing or Braiding
by Magda Silva, Isabel Pinho, Hugo Gonçalves, Ana C. Vale, Maria C. Paiva, Natália M. Alves and José A. Covas
J. Compos. Sci. 2023, 7(3), 104; https://doi.org/10.3390/jcs7030104 - 07 Mar 2023
Cited by 2 | Viewed by 1592
Abstract
The development of scaffolds for tissue-engineered growth of the anterior cruciate ligament (ACL) is a promising approach to overcome the limitations of current solutions. This work proposes novel biodegradable and biocompatible scaffolds matching the mechanical characteristics of the native human ligament. Poly(L-lactic acid) [...] Read more.
The development of scaffolds for tissue-engineered growth of the anterior cruciate ligament (ACL) is a promising approach to overcome the limitations of current solutions. This work proposes novel biodegradable and biocompatible scaffolds matching the mechanical characteristics of the native human ligament. Poly(L-lactic acid) (PLA) scaffolds reinforced with graphite nano-platelets (PLA+EG) as received, chemically functionalized (PLA+f-EG), or functionalized and decorated with silver nanoparticles [PLA+((f-EG)+Ag)], were fabricated by conventional braiding and using 3D-printing technology. The dimensions of both braided and 3D-printed scaffolds were finely controlled. The results showed that the scaffolds exhibited high porosity (>60%), pore interconnectivity, and pore size suitable for ligament tissue ingrowth, with no relevant differences between PLA and composite scaffolds. The wet state dynamic mechanical analysis at 37 °C revealed an increase in the storage modulus of the composite constructs, compared to neat PLA scaffolds. Either braided or 3D-printed scaffolds presented storage modulus values similar to those found in soft tissues. The tailorable design of the braided structures, as well as the reproducibility, the high speed, and the simplicity of 3D-printing allowed to obtain two different scaffolds suitable for ligament tissue engineering. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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20 pages, 13661 KiB  
Article
Design, Simulation, and Mechanical Testing of 3D-Printed Titanium Lattice Structures
by Klaudio Bari
J. Compos. Sci. 2023, 7(1), 32; https://doi.org/10.3390/jcs7010032 - 11 Jan 2023
Cited by 3 | Viewed by 2190
Abstract
Lattice structure topology is a rapidly growing area of research facilitated by developments in additive manufacturing. These low-density structures are particularly promising for their medical applications. However, predicting their performance becomes a challenging factor in their use. In this article, four lattice topologies [...] Read more.
Lattice structure topology is a rapidly growing area of research facilitated by developments in additive manufacturing. These low-density structures are particularly promising for their medical applications. However, predicting their performance becomes a challenging factor in their use. In this article, four lattice topologies are explored for their suitability as implants for the replacement of segmental bone defects. The study introduces a unit-cell concept for designing and manufacturing four lattice structures, BCC, FCC, AUX, and ORG, using direct melt laser sintering (DMLS). The elastic modulus was assessed using an axial compression strength test and validated using linear static FEA simulation. The outcomes of the simulation revealed the disparity between the unit cell and the entire lattice in the cases of BCC, FCC, and AUX, while the unit-cell concept of the full lattice structure was successful in ORG. Measurements of energy absorption obtained from the compression testing revealed that the ORG lattice had the highest absorbed energy (350 J) compared with the others. The observed failure modes indicated a sudden collapsing pattern during the compression test in the cases of BCC and FCC designs, while our inspired ORG and AUX lattices outperformed the others in terms of their structural integrity under identical loading conditions. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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18 pages, 4938 KiB  
Article
Parametric Design and Mechanical Characterization of 3D-Printed PLA Composite Biomimetic Voronoi Lattices Inspired by the Stereom of Sea Urchins
by Alexandros Efstathiadis, Ioanna Symeonidou, Konstantinos Tsongas, Emmanouil K. Tzimtzimis and Dimitrios Tzetzis
J. Compos. Sci. 2023, 7(1), 3; https://doi.org/10.3390/jcs7010003 - 26 Dec 2022
Cited by 8 | Viewed by 2110
Abstract
The present work is focused on the analysis of the microstructure of the exoskeleton of the sea urchin Paracentrotus lividus and the extraction of design concepts by implementing geometrically described 3D Voronoi diagrams. Scanning electron microscopy (SEM) analysis of dried sea urchin shells [...] Read more.
The present work is focused on the analysis of the microstructure of the exoskeleton of the sea urchin Paracentrotus lividus and the extraction of design concepts by implementing geometrically described 3D Voronoi diagrams. Scanning electron microscopy (SEM) analysis of dried sea urchin shells revealed a foam-like microstructure, also known as the stereom. Subsequently, parametric, digital models were created with the aid of the computer-aided design (CAD) software Rhinoceros 3D (v. Rhino 7, 7.1.20343.09491) combined with the visual programming environment Grasshopper. Variables such as node count, rod thickness and mesh smoothness of the biologically-inspired Voronoi lattice were adapted for 3D printing cubic specimens using the fused filament fabrication (FFF) method. The filaments used in the process were a commercial polylactic acid (PLA), a compound of polylactic acid/polyhydroxyalkanoate (PLA/PHA) and a wood fiber polylactic acid/polyhydroxyalkanoate (PLA/PHA) composite. Nanoindentation tests coupled with finite element analysis (FEA) produced the stress–strain response of the materials under study and were used to simulate the Voronoi geometries under a compression loading regime in order to study their deformation and stress distribution in relation to experimental compression testing. The PLA blend with polyhydroxyalkanoate seems to have a minor effect on the mechanical behavior of such structures, whereas when wood fibers are added to the compound, a major decrease in strength occurs. The computational model results significantly coincide with the experimental results. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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17 pages, 5887 KiB  
Article
The Impact of Zinc Oxide Micro-Powder Filler on the Physical and Mechanical Response of High-Density Polyethylene Composites in Material Extrusion 3D Printing
by Nectarios Vidakis, Markos Petousis, Athena Maniadi, Vassilis Papadakis and Amalia Moutsopoulou
J. Compos. Sci. 2022, 6(10), 315; https://doi.org/10.3390/jcs6100315 - 14 Oct 2022
Cited by 5 | Viewed by 1953
Abstract
The scope of this work was to develop novel polymer composites via melt extrusion and 3D printing, incorporating High-Density Polyethylene filled with zinc oxide particles in various wt. percentages. For each case scenario, a filament of approximately 1.75 mm in diameter was fabricated. [...] Read more.
The scope of this work was to develop novel polymer composites via melt extrusion and 3D printing, incorporating High-Density Polyethylene filled with zinc oxide particles in various wt. percentages. For each case scenario, a filament of approximately 1.75 mm in diameter was fabricated. Samples for tensile and flexural testing were fabricated with 3D printing. They were then evaluated for their mechanical response according to ASTM standards. According to the documented testing data, the filler increases the mechanical strength of pure HDPE at specific filler concentrations. The highest values reported were a 54.6% increase in the flexural strength with HDPE/ZnO 0.5 wt.% and a 53.8% increase in the tensile strength with 10 wt.% ZnO loading in the composite. Scanning Electron Microscopy (SEM), Raman, and thermal characterization techniques were used. The experimental findings were evaluated in other research areas where they were applicable. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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16 pages, 4490 KiB  
Article
Process Optimization for the 3D Printing of PLA and HNT Composites with Arburg Plastic Freeforming
by Leonardo G. Engler, Janaina S. Crespo, Noel M. Gately, Ian Major and Declan M. Devine
J. Compos. Sci. 2022, 6(10), 309; https://doi.org/10.3390/jcs6100309 - 12 Oct 2022
Cited by 1 | Viewed by 1762
Abstract
The industrial use of additive manufacturing continues to rapidly increase as new technology developments become available. The Arburg plastic freeforming (APF) process is designed to utilize standard polymeric granules in order to print parts with properties similar to those of molded parts. Despite [...] Read more.
The industrial use of additive manufacturing continues to rapidly increase as new technology developments become available. The Arburg plastic freeforming (APF) process is designed to utilize standard polymeric granules in order to print parts with properties similar to those of molded parts. Despite the emerging industrial importance of APF, the current body of knowledge regarding this technology is still very limited, especially in the field of biodegradable polymer composites. To this end, poly(lactic acid) (PLA) was reinforced with halloysite nanotubes (HNTs) by hot melt extrusion. The PLA/HNT (0–10 wt%.) composites were analyzed in terms of their rheology, morphology, and thermal and mechanical properties. A study of the processing properties of these composites in the context of APF was performed to ensure the consistency of 3D-printed, high-quality components. The optimized machine settings were used to evaluate the tensile properties of specimens printed with different axis orientations (XY and XZ) and deposition angles (0 and 45°). Specimens printed with an XY orientation and deposition angle starting at 0° resulted in the highest mechanical properties. In this study, the use of PLA/HNT composites in an APF process was reported for the first time, and the current methodology achieved satisfactory results in terms of the 3D printing and evaluation of successful PLA/HNT composites to be used as feedstock in an APF process. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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16 pages, 8876 KiB  
Article
MEX 3D Printed HDPE/TiO2 Nanocomposites Physical and Mechanical Properties Investigation
by Nectarios Vidakis, Markos Petousis, Athena Maniadi, Vassilis Papadakis and Alexandra Manousaki
J. Compos. Sci. 2022, 6(7), 209; https://doi.org/10.3390/jcs6070209 - 15 Jul 2022
Cited by 14 | Viewed by 1859
Abstract
Aiming to develop more robust, mechanically advanced, Fused Filament Fabrication (FFF) materials, High-Density Polyethylene (HDPE) nanocomposites were developed in the current research work. Titanium Dioxide (TiO2) was selected as filler to be incorporated into the HDPE matrix in concentration steps of [...] Read more.
Aiming to develop more robust, mechanically advanced, Fused Filament Fabrication (FFF) materials, High-Density Polyethylene (HDPE) nanocomposites were developed in the current research work. Titanium Dioxide (TiO2) was selected as filler to be incorporated into the HDPE matrix in concentration steps of 0.5, 2.5, 5, and 10 wt.%. 3D printing nanocomposite filaments were extruded in ~1.75 mm diameter and used to 3D print and test tensile and flexion specimens according to international standards. Reported results indicate that the filler contributes to increasing the mechanical strength of the virgin HDPE at certain filler and filler type concentrations; with the highest values reported to be 37.8% higher in tensile strength with HDPE/TiO2 10 wt.%. Morphological and thermal characterization was performed utilizing Scanning Electron Microscopy (SEM), Raman, Thermogravimetric Analysis (TGA), and Differential Scanning Calorimetry (DSC), while the results were correlated with the available literature. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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16 pages, 7413 KiB  
Article
Mechanical Properties and Energy-Absorption Capability of a 3D-Printed TPMS Sandwich Lattice Model for Meta-Functional Composite Bridge Bearing Applications
by Pasakorn Sengsri, Hao Fu and Sakdirat Kaewunruen
J. Compos. Sci. 2022, 6(3), 71; https://doi.org/10.3390/jcs6030071 - 24 Feb 2022
Cited by 10 | Viewed by 3315
Abstract
This paper reports on a proposed novel 3D-printed sandwich lattice model using a triply periodic minimal surface (TPMS) structure for meta-functional composite bridge bearings (MFCBBs). It could be implemented in bridge systems, including buildings and railway bridges. A TMPS structure offers a high [...] Read more.
This paper reports on a proposed novel 3D-printed sandwich lattice model using a triply periodic minimal surface (TPMS) structure for meta-functional composite bridge bearings (MFCBBs). It could be implemented in bridge systems, including buildings and railway bridges. A TMPS structure offers a high performance to density ratio under different loading. Compared to typical elastomeric bridge bearings with any reinforcements, the use of 3D-printed TPMS sandwich lattices could potentially lead to a substantial reduction in both manufacturing cost and weight, but also to a significant increase in recyclability with their better mechanical properties (compressive, crushing, energy absorption, vibration, and sound attenuation). This paper shows predictions from a numerical study performed to examine the behaviour of a TPMS sandwich lattice model under two different loading conditions for bridge bearing applications. The validation of the modelling is compared with experimental results to ensure the possibility of designing and fabricating a 3D-printed TPMS sandwich lattice for practical use. In general, the compressive experimental and numerical load–displacement behaviour of the TPMS unit cell are in excellent agreement within the elastic limit region. Moreover, its failure mode for bridge bearing applications has been identified as an elastic–plastic and hysteretic failure behaviour under uniaxial compression and combined compression–shear loading, respectively. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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12 pages, 2605 KiB  
Article
3D Printing under High Ambient Pressures and Improvement of Mechanical Properties of Printed Parts
by Yousuf Pasha Shaik, Jens Schuster, Harshavardhan Reddy Katherapalli and Aarif Shaik
J. Compos. Sci. 2022, 6(1), 16; https://doi.org/10.3390/jcs6010016 - 05 Jan 2022
Cited by 8 | Viewed by 3206
Abstract
Contrary to other polymer processing methods, additive manufacturing processes do not require any pressure during the consolidation of layers. This study investigates the effect of high ambient pressure on the consolidation of layers during the FDM process and their analysis of mechanical properties. [...] Read more.
Contrary to other polymer processing methods, additive manufacturing processes do not require any pressure during the consolidation of layers. This study investigates the effect of high ambient pressure on the consolidation of layers during the FDM process and their analysis of mechanical properties. An experimental setup was arranged, consisting of a 3D printer integrated into a customized Autoclave, to achieve high strength properties for 3D printed parts as like injection-molded specimens. The autoclave can maintain 135 bar of pressure and a maximum temperature of 185 °C. 3D printing with PLA was carried out at 0 bar, 5 bar, and 10 bar. Tensile, flexural, and Charpy tests were conducted on printed specimens, and the effect of pressure and temperature on 3D-printed samples were analyzed. It could be shown that autoclave preheating before printing and autoclave pressure during printing improves the consolidation of layers immensely. The pressure inside the autoclave provokes a more intimate contact between the layer surfaces and results in higher mechanical properties such as yield strength, Young’s modulus, and impact strength. The properties could be raised 100%. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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18 pages, 5430 KiB  
Article
Mechanical and FEA-Assisted Characterization of 3D Printed Continuous Glass Fiber Reinforced Nylon Cellular Structures
by Evangelos Giarmas, Konstantinos Tsongas, Emmanouil K. Tzimtzimis, Apostolos Korlos and Dimitrios Tzetzis
J. Compos. Sci. 2021, 5(12), 313; https://doi.org/10.3390/jcs5120313 - 27 Nov 2021
Cited by 8 | Viewed by 2731
Abstract
The main objective of this study was to investigate the mechanical behavior of 3D printed fiberglass-reinforced nylon honeycomb structures. A Continuous Fiber Fabrication (CFF) 3D printer was used since it makes it possible to lay continuous strands of fibers inside the 3D printed [...] Read more.
The main objective of this study was to investigate the mechanical behavior of 3D printed fiberglass-reinforced nylon honeycomb structures. A Continuous Fiber Fabrication (CFF) 3D printer was used since it makes it possible to lay continuous strands of fibers inside the 3D printed geometries at selected locations across the width in order to optimize the bending behavior. Nylon and nylon/fiberglass honeycomb structures were tested under a three-point bending regime. The microstructure of the filaments and the 3D printed fractured surfaces following bending tests were examined with Scanning Electron Microscopy (SEM). The modulus of the materials was also evaluated using the nanoindentation technique. The behavior of the 3D printed structures was simulated with a Finite Element Model (FEM). The experimental and simulation results demonstrated that 3D printed continuous fiberglass reinforcement is possible to selectively adjust the bending strength of the honeycombs. When glass fibers are located near the top and bottom faces of honeycombs, the bending strength is maximized. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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18 pages, 4432 KiB  
Article
Maximizing the Performance of 3D Printed Fiber-Reinforced Composites
by S M Fijul Kabir, Kavita Mathur and Abdel-Fattah M. Seyam
J. Compos. Sci. 2021, 5(5), 136; https://doi.org/10.3390/jcs5050136 - 18 May 2021
Cited by 12 | Viewed by 3865
Abstract
Fiber-reinforced 3D printing technology offers significant improvement in the mechanical properties of the resulting composites relative to 3D printed (3DP) polymer-based composites. However, 3DP fiber-reinforced composite structures suffer from low fiber content compared to the traditional composite, such as 3D orthogonal woven preforms [...] Read more.
Fiber-reinforced 3D printing technology offers significant improvement in the mechanical properties of the resulting composites relative to 3D printed (3DP) polymer-based composites. However, 3DP fiber-reinforced composite structures suffer from low fiber content compared to the traditional composite, such as 3D orthogonal woven preforms solidified with vacuum assisted resin transfer molding (VARTM) that impedes their high-performance applications such as in aerospace, automobile, marine and building industries. The present research included fabrication of 3DP fiberglass-reinforced nylon composites, with maximum possible fiber content dictated by the current 3D printing technology at varying fiber orientations (such as 0/0, 0/90, ±45 and 0/45/90/−45) and characterizing their microstructural and performance properties, such as tensile and impact resistance (Drop-weight, Izod and Charpy). Results indicated that fiber orientation with maximum fiber content have tremendous effect on the improvement of the performance of the 3DP composites, even though they inherently contain structural defects in terms of voids resulting in premature failure of the composites. Benchmarking the results with VARTM 3D orthogonal woven (3DOW) composites revealed that 3DP composites had slightly lower tensile strength due to poor matrix infusion and voids between adjacent fiber layers/raster, and delamination due to lack of through-thickness reinforcement, but excellent impact strength (224% more strong) due to favorable effect of structural voids and having a laminated structure developed in layer-by-layer fashion. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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15 pages, 5960 KiB  
Article
3D Printed Hierarchical Honeycombs with Carbon Fiber and Carbon Nanotube Reinforced Acrylonitrile Butadiene Styrene
by Michel Theodor Mansour, Konstantinos Tsongas and Dimitrios Tzetzis
J. Compos. Sci. 2021, 5(2), 62; https://doi.org/10.3390/jcs5020062 - 21 Feb 2021
Cited by 13 | Viewed by 5080
Abstract
The mechanical properties of Fused Filament Fabrication (FFF) 3D printed specimens of acrylonitrile butadiene styrene (ABS), ABS reinforced with carbon fibers (ABS/CFs) and ABS reinforced with carbon nanotubes (ABS/CNTs) are investigated in this paper using various experimental tests. In particular, the mechanical performance [...] Read more.
The mechanical properties of Fused Filament Fabrication (FFF) 3D printed specimens of acrylonitrile butadiene styrene (ABS), ABS reinforced with carbon fibers (ABS/CFs) and ABS reinforced with carbon nanotubes (ABS/CNTs) are investigated in this paper using various experimental tests. In particular, the mechanical performance of the fabricated specimens was determined by conducting compression and cyclic compression testing, as well as nanoindentation tests. In addition, the design and the manufacturing of hierarchical honeycomb structures are presented using the materials under study. The 3D printed honeycomb structures were examined by uniaxial compressive tests to review the mechanical behavior of such cellular structures. The compressive performance of the hierarchical honeycomb structures was also evaluated with finite element analysis (FEA) in order to extract the stress-strain response of these structures. The results revealed that the 2nd order hierarchy displayed increased stiffness and strength as compared with the 0th and the 1st hierarchies. Furthermore, the addition of carbon fibers in the ABS matrix improved the stiffness, the strength and the hardness of the FFF printed specimens as well as the compression performance of the honeycomb structures. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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Review

Jump to: Research

37 pages, 2988 KiB  
Review
Polymer-Based Materials Built with Additive Manufacturing Methods for Orthopedic Applications: A Review
by Kunal Manoj Gide, Sabrina Islam and Z. Shaghayegh Bagheri
J. Compos. Sci. 2022, 6(9), 262; https://doi.org/10.3390/jcs6090262 - 08 Sep 2022
Cited by 4 | Viewed by 2604
Abstract
Over the last few decades, polymers and their composites have shown a lot of promises in providing more viable alternatives to surgical procedures that require scaffolds and implants. With the advancement in biomaterial technologies, it is possible to overcome the limitations of current [...] Read more.
Over the last few decades, polymers and their composites have shown a lot of promises in providing more viable alternatives to surgical procedures that require scaffolds and implants. With the advancement in biomaterial technologies, it is possible to overcome the limitations of current methods, including auto-transplantation, xeno-transplantation, and the implantation of artificial mechanical organs used to treat musculoskeletal conditions. The risks associated with these methods include complications, secondary injuries, and limited sources of donors. Three-dimensional (3D) printing technology has the potential to resolve some of these limitations. It can be used for the fabrication of tailored tissue-engineering scaffolds, and implants, repairing tissue defects in situ with cells, or even printing tissues and organs directly. In addition to perfectly matching the patient’s damaged tissue, printed biomaterials can have engineered microstructures and cellular arrangements to promote cell growth and differentiation. As a result, such biomaterials allow the desired tissue repair to be achieved, and could eventually alleviate the shortage of organ donors. As such, this paper provides an overview of different 3D-printed polymers and their composites for orthopedic applications reported in the literature since 2010. For the benefit of the readers, general information regarding the material, the type of manufacturing method, and the biomechanical tests are also reported. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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21 pages, 7643 KiB  
Review
State-of-the-Art Review on Additive Manufacturing Technology in Railway Infrastructure Systems
by Hao Fu and Sakdirat Kaewunruen
J. Compos. Sci. 2022, 6(1), 7; https://doi.org/10.3390/jcs6010007 - 27 Dec 2021
Cited by 11 | Viewed by 4766
Abstract
Additive manufacturing technologies, well known as three-dimensional printing (3DP) technologies, have been applied in many industrial fields, including aerospace, automobiles, shipbuilding, civil engineering and nuclear power. However, despite the high material utilization and the ability to rapidly construct complex shaped structures of 3D [...] Read more.
Additive manufacturing technologies, well known as three-dimensional printing (3DP) technologies, have been applied in many industrial fields, including aerospace, automobiles, shipbuilding, civil engineering and nuclear power. However, despite the high material utilization and the ability to rapidly construct complex shaped structures of 3D printing technologies, the application of additive manufacturing technologies in railway track infrastructure is still at the exploratory stage. This paper reviews the state-of-the-art research of additive manufacturing technologies related the railway track infrastructure and discusses the challenges and prospects of 3D printing technology in this area. The insights will not only help the development of 3D printing technologies into railway engineering but also enable smarter railway track component design and improve track performance and inspection strategies. Full article
(This article belongs to the Special Issue 3D Printing Composites)
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