Advances in Polymeric Additive Manufacturing

A special issue of Polymers (ISSN 2073-4360). This special issue belongs to the section "Polymer Physics and Theory".

Deadline for manuscript submissions: 30 September 2024 | Viewed by 13692

Special Issue Editors


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Guest Editor
Department of Mechanical and Biomedical Engineering, Ewha Womans University, Seoul, Republic of Korea
Interests: multimaterial forming; thermoplastic polymers; metal forging and forming; machine learning; additive manufacturing; biomedical devices; unfilled thermoset polymers
College of Material Science and Engineering, Ocean University of China, Qingdao 266100, China
Interests: fiber reinforced composites; marine biomaterial; multiscale simulation; structural mechanics
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Special Issue Information

Dear Colleagues,

Polymeric additive manufacturing (AM) has become a research topic in which an ever-growing number of scientists and researchers are investing a considerable amount of time and effort aiming to improve and advance both basic knowledge and application capabilities. Thanks to the high degree of freedom granted by processes such as SLA, in terms of designable geometry and employable materials, its applications are vast and interdisciplinary.

However, polymeric materials are intrinsically influenced by the processing environment and the curing conditions, a fact which results in variabilities of the mechanical response and fracture behavior. Understanding the influence between process conditions and the mechanical response of the designed component is essential to bring polymeric AM to the next step in its technological evolution, for a wide and reliable technology transfer to industry.

Hence, this Special Issue aims to enhance our understanding of the influences among materials, processes, and part design for additively manufactured components, especially in terms of their influence on final mechanical performances, such as elastic properties, strength, failure, and fatigue behavior. Contributions dealing with polymers, short fiber-reinforced polymers, long fiber-reinforced polymers, metal composite multi-materials, and biomedical materials-based additive manufacturing are welcome. Both experimental and numerical contributions are invited. Case studies on additive manufacturing applications are also welcome if a clear scientific connection among design, process, and product is established.

Prof. Dr. Luca Quagliato
Prof. Dr. Kai Jin
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Polymers is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • addictive manufacturing
  • unfilled thermoset polymers
  • reinforced plastic additive manufacturing
  • continuous fiber additive manufacturing
  • deposition strategy
  • curing conditions
  • anisotropy
  • shape design procedures
  • topology optimization

Published Papers (7 papers)

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Research

29 pages, 9066 KiB  
Article
Applicability of a Material Constitutive Model Based on a Transversely Isotropic Behaviour for the Prediction of the Mechanical Performance of Multi Jet Fusion Printed Polyamide 12 Parts
by Sergio Perez-Barcenilla, Xabier Cearsolo, Amaia Aramburu, Ruben Castano-Alvarez, Juan R. Castillo and Jorge Gayoso Lopez
Polymers 2024, 16(1), 56; https://doi.org/10.3390/polym16010056 - 23 Dec 2023
Cited by 1 | Viewed by 807
Abstract
Multi Jet Fusion (MJF), an innovative additive manufacturing (AM) technique in the field of Powder Bed Fusion (PBF) developed by Hewlett-Packard (HP) Inc. (Palo Alto, CA, USA), has been designed to produce polymer parts using thermoplastic-based powders, primarily focusing on polyamide 12 (PA12). [...] Read more.
Multi Jet Fusion (MJF), an innovative additive manufacturing (AM) technique in the field of Powder Bed Fusion (PBF) developed by Hewlett-Packard (HP) Inc. (Palo Alto, CA, USA), has been designed to produce polymer parts using thermoplastic-based powders, primarily focusing on polyamide 12 (PA12). Employing a layer-by-layer approach, MJF enables the rapid production of intricate components, reportedly up to 10 times faster than other AM processes. While the mechanical properties of MJF-printed PA12 and the impact of build orientation on those properties have already been explored in various studies, less attention has been given to the mechanical performance of MJF-printed PA12 components under complex loads and accurate predictive models. This contribution aims to assess the applicability of a constitutive model based on a transversely isotropic behaviour under linear elastic deformation for predicting the mechanical response of MJF-printed PA12 parts through numerical simulations. Both uniaxial tensile and shear tests were carried out on printed samples to determine the elastic properties of MJF-printed PA12, with additional testing on printed complex handle-shaped parts. Finally, a numerical model was developed to simulate the mechanical tests of the handles. Results from tests on printed samples showed that MJF-printed PA12, to some extent, behaves as a transversely isotropic material. Furthermore, using a constitutive model that assumes a transversely isotropic behaviour under linear elastic deformation for predicting the mechanical response of MJF-printed PA12 parts in numerical simulations could be a reasonable approach, provided that the material stress levels remain within the linear range. However, the particularities of the stress-strain curve of MJF-printed PA12 complicate determining the elasticity-to-plasticity transition point. Full article
(This article belongs to the Special Issue Advances in Polymeric Additive Manufacturing)
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17 pages, 7241 KiB  
Article
Effect of Shock-Variable Environmental Temperature and Humidity Conditions on 3D-Printed Polymers for Tensile Properties
by Marcin Głowacki, Katarzyna Skórczewska, Krzysztof Lewandowski, Piotr Szewczykowski and Adam Mazurkiewicz
Polymers 2024, 16(1), 1; https://doi.org/10.3390/polym16010001 - 19 Dec 2023
Cited by 2 | Viewed by 1539
Abstract
The article presents the research results on the influence of variable shock conditions, such as temperature and water, thus reflecting shock atmospheric conditions during freezing and thawing, on the properties of samples produced using 3D printing technology from commonly used materials such as [...] Read more.
The article presents the research results on the influence of variable shock conditions, such as temperature and water, thus reflecting shock atmospheric conditions during freezing and thawing, on the properties of samples produced using 3D printing technology from commonly used materials such as ABS, HIPS, PLA, and ASA. Understanding how different environmental conditions affect the quality, reliability, and durability of 3D prints can help to optimize the printing process and provide valuable information about their application possibilities. Tests related to the strength of the materials, such as static tensile testing, Charpy impact testing, and evaluation of structures, were carried out using a scanning electron microscope (SEM). Changes in chemical properties were measured by performing tests such as FTIR and TGA. Variations in chemical properties were measured by performing tests such as FTIR and TGA. One shock cycle lasting 7 days was sufficient to alter the properties of 3D prints, with the extent of changes depending on the material, as summarized in the test results. Full article
(This article belongs to the Special Issue Advances in Polymeric Additive Manufacturing)
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16 pages, 10468 KiB  
Article
Manufacturing Process, Tensile-Compressive, and Impact Properties of Tungsten (W)-Particle-Reinforced SLA Methacrylate
by Mattia Perin, Luca Quagliato, Guido A. Berti, Changsoon Jang, Sewon Jang and Taeyong Lee
Polymers 2023, 15(24), 4728; https://doi.org/10.3390/polym15244728 - 17 Dec 2023
Viewed by 1068
Abstract
The interest in research and development for additive manufacturing (AM) processes has grown significantly over the last years and attracts both industry and academia alike. Among the available AM technologies, stereolithography (SLA) is one of the most discussed, researched, and employed. On the [...] Read more.
The interest in research and development for additive manufacturing (AM) processes has grown significantly over the last years and attracts both industry and academia alike. Among the available AM technologies, stereolithography (SLA) is one of the most discussed, researched, and employed. On the other hand, being based on thermoset resins, all the limitations of this typology of materials still apply, limiting the range of applications of this highly versatile process. To overcome these limitations, especially brittleness, this research analyzes the effects of Tungsten (W) micro-size (average size 1 μm) particles reinforcement on a methacrylate base material. First, the manufacturing process for creating the W-reinforced methacrylate material is presented and investigated to define the effect of pre- and post-processing operations on the quality of the pre-cured solution considering 4% and 10% wt. W particles concentrations. Afterward, tensile, compressive, and impact specimens were manufactured with both concentrations and compared with the experimental results from clear (unfilled) resin-based specimens used as the benchmark. The addition of tungsten particles showed a strong improvement in the impact strength of the methacrylate base material, quantified in 28% for the 4% and 55% for the 10% wt., respectively, although at the expense of a slight reduction in elastic and yield properties on average −12%. Furthermore, using Scanning Electron Microscope (SEM) analyses, the particle–matrix interaction was investigated, showing the interaction between the polymer matrix and the reinforcement and the mechanism by which the impact resistance is enhanced. Full article
(This article belongs to the Special Issue Advances in Polymeric Additive Manufacturing)
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15 pages, 7192 KiB  
Article
Material Extrusion 3D Printing of PEEK-Based Composites
by Thomas Hanemann, Alexander Klein, Siegfried Baumgärtner, Judith Jung, David Wilhelm and Steffen Antusch
Polymers 2023, 15(16), 3412; https://doi.org/10.3390/polym15163412 - 15 Aug 2023
Cited by 6 | Viewed by 1791
Abstract
High-performance thermoplastics like polyetheretherketone (PEEK), with their outstanding thermal stability, mechanical properties and chemical stability, have great potential for various structural applications. Combining with additive manufacturing methods extends further PEEK usage, e.g., as a mold insert material in polymer melt processing like injection [...] Read more.
High-performance thermoplastics like polyetheretherketone (PEEK), with their outstanding thermal stability, mechanical properties and chemical stability, have great potential for various structural applications. Combining with additive manufacturing methods extends further PEEK usage, e.g., as a mold insert material in polymer melt processing like injection molding. Mold inserts must possess a certain mechanical stability, a low surface roughness as well as a good thermal conductivity for the temperature control during the molding process. With this in mind, the commercially available high-performance thermoplastic PEEK was doped with small amounts of carbon nanotubes (CNT, 6 wt%) and copper particles (10 wt%) targeting enhanced thermomechanical properties and a higher thermal conductivity. The composites were realized by a commercial combined compounder and filament maker for the usage in a material extrusion (MEX)-based 3D-printer following the fused filament fabrication (FFF) principle. Commercial filaments made from PEEK and carbon fiber reinforced PEEK were used as reference systems. The impact of the filler and the MEX printing conditions like printing temperature, printing speed and infill orientation on the PEEK properties were characterized comprehensively by tensile testing, fracture imaging and surface roughness measurements. In addition, the thermal conductivity was determined by the laser-flash method in combination with differential scanning calorimetry and Archimedes density measurement. The addition of fillers did not alter the measured tensile strength in comparison to pure PEEK significantly. The fracture images showed a good printing quality without the MEX-typical voids between and within the deposited layers. Higher printing temperatures caused a reduction of the surface roughness and, in some cases, an enhanced ductile behavior. The thermal conductivity could be increased by the addition of the CNTs. Following the given results, the most critical process step is the compounding procedure, because for a reliable process–parameter–property relationship, a homogeneous particle distribution in the polymer matrix yielding a reliable filament quality is essential. Full article
(This article belongs to the Special Issue Advances in Polymeric Additive Manufacturing)
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17 pages, 1508 KiB  
Article
Solid Rocket Propellant Photo-Polymerization with an In-House LED-UV Prototype
by Andrea Galavotti, Camilla Noè, Giovanni Polizzi, Paola Antonaci, Filippo Maggi, Filippo Masseni and Dario Pastrone
Polymers 2023, 15(7), 1633; https://doi.org/10.3390/polym15071633 - 24 Mar 2023
Cited by 4 | Viewed by 2649
Abstract
Composite solid propellants have used cast molding production technology for many decades, with intrinsic limitations on production flexibility, promptness, and grain geometry, as well as environmental implications on toxicity and global carbon footprint. This traditional method involves the use of toxic chemicals, has [...] Read more.
Composite solid propellants have used cast molding production technology for many decades, with intrinsic limitations on production flexibility, promptness, and grain geometry, as well as environmental implications on toxicity and global carbon footprint. This traditional method involves the use of toxic chemicals, has a long processing time, requires high temperature, and the products have limited geometries. To overcome those issues, different photo-curable resins have been evaluated as possible matrices. In fact, the UV-curing process is fast and has low energy consumption. The photocuring reaction parameters of six different pristine formulations were evaluated by Fourier transform infrared spectroscopy analysis. After finding the optimal curing parameters, different composites were prepared by adding 75 or 80 wt% ammonium sulfate particles used as an inert replacement for the oxidant. The thermomechanical properties and thermal resistance of the UV-cured composites were characterized via dynamic thermal-mechanical and thermogravimetric analysis. Subsequently, the mechanical properties of the inert propellants were investigated by tensile tests. The most promising resin systems for the production of solid rocket propellants were then 3D printed by an in-house developed illumination system and the obtained object micro-structure was evaluated by X-ray computed tomography. Full article
(This article belongs to the Special Issue Advances in Polymeric Additive Manufacturing)
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17 pages, 3207 KiB  
Article
Development of Bisphenol-A-Glycidyl-Methacrylate- and Trimethylolpropane-Triacrylate-Based Stereolithography 3D Printing Materials
by Yura Choi, Jisun Yoon, Jinyoung Kim, Choongjae Lee, Jaesang Oh and Namchul Cho
Polymers 2022, 14(23), 5198; https://doi.org/10.3390/polym14235198 - 29 Nov 2022
Cited by 6 | Viewed by 2332
Abstract
The main advantages of the three-dimensional (3D) printing process are flexible design, rapid prototyping, multi-component structures, and minimal waste. For stereolithography (SLA) 3D printing, common photocurable polymers, such as bisphenol-A glycidyl methacrylate (Bis-EMA), trimethylolpropane triacrylate (TMPTMA), as well as urethane oligomers, have been [...] Read more.
The main advantages of the three-dimensional (3D) printing process are flexible design, rapid prototyping, multi-component structures, and minimal waste. For stereolithography (SLA) 3D printing, common photocurable polymers, such as bisphenol-A glycidyl methacrylate (Bis-EMA), trimethylolpropane triacrylate (TMPTMA), as well as urethane oligomers, have been widely used. For a successful 3D printing process, these photocurable polymers must satisfy several requirements, including transparency, a low viscosity, good mechanical strength, and low shrinkage post-ultraviolet curing process. Herein, we investigated SLA-type photocurable resins prepared using Bis-EMA, TMPTMA, and urethane oligomers. The flexural strength, hardness, conversion rate, output resolution, water absorption, and solubility of the printed materials were investigated. The degree of conversion of the printed specimens measured by infrared spectroscopy ranged from 30 to 60%. We also observed that 64–80 MPa of the flexural strength, 40–60 HV of the surface hardness, 15.6–29.1 MPa of the compression strength, and 3.3–14.5 MPa of the tensile strength. The output resolution was tested using three different structures comprising a series of columns (5–50 mm), circles (0.6–6 mm), and lines (0.2–5 mm). In addition, we used five different pigments to create colored resins and successfully printed complex models of the Eiffel Tower. The research on resins, according to the characteristics of these materials, will help in the design of new materials. These results suggests that acrylate-based resins have the potential for 3D printing. Full article
(This article belongs to the Special Issue Advances in Polymeric Additive Manufacturing)
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13 pages, 5835 KiB  
Article
Validation of the Mechanical Behavior of an Aeronautical Fixing Turret Produced by a Design for Additive Manufacturing (DfAM)
by Fernando Veiga, Trunal Bhujangrao, Alfredo Suárez, Eider Aldalur, Igor Goenaga and Daniel Gil-Hernandez
Polymers 2022, 14(11), 2177; https://doi.org/10.3390/polym14112177 - 27 May 2022
Cited by 10 | Viewed by 1966
Abstract
The design of parts in such critical sectors as the manufacturing of aeronautical parts is awaiting a paradigm shift due to the introduction of additive manufacturing technologies. The manufacture of parts designed by means of the design-oriented additive manufacturing methodology (DfAM) has acquired [...] Read more.
The design of parts in such critical sectors as the manufacturing of aeronautical parts is awaiting a paradigm shift due to the introduction of additive manufacturing technologies. The manufacture of parts designed by means of the design-oriented additive manufacturing methodology (DfAM) has acquired great relevance in recent years. One of the major gaps in the application of these technologies is the lack of studies on the mechanical behavior of parts manufactured using this methodology. This paper focuses on the manufacture of a turret for the clamping of parts for the aeronautical industry. The design of the lightened turret by means of geometry optimization, the manufacture of the turret in polylactic acid (PLA) and 5XXX series aluminum alloy by means of Wire Arc Additive Manufacturing (WAAM) technology and the analysis by means of finite element analysis (FEA) with its validation by means of a tensile test are presented. The behavior of the part manufactured with both materials is compared. The conclusion allows to establish which are the limitations of the part manufactured in PLA for its orientation to the final application, whose advantages are its lower weight and cost. This paper is novel as it presents a holistic view that covers the process in an integrated way from the design and manufacture to the behaviour of the component in use. Full article
(This article belongs to the Special Issue Advances in Polymeric Additive Manufacturing)
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