Submit to Polymers Review for Polymers Propose a Special Issue

Journal Menu

Journal Browser

Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing

Print Special Issue Flyer
Special Issue Editors
Special Issue Information
Keywords
Benefits of Publishing in a Special Issue
Published Papers

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

Deadline for manuscript submissions: closed (31 January 2022) | Viewed by 60856

Share This Special Issue

Special Issue Editors

Dr. Giovanni Gómez-Gras

E-Mail Website
Guest Editor

Industrial Engineering Department, IQS School of Engineering, Universitat Ramon Llull, 08022 Barcelona, Spain
Interests: additive manufacturing; advanced manufacturing; ball burnishing; fatigue; material characterization; design for manufacturing

Dr. Marco A. Pérez

E-Mail Website
Guest Editor

Industrial Engineering Department, IQS School of Engineering, Universitat Ramon Llull, 08022 Barcelona, Spain
Interests: experimental mechanics; vibration-based methods; non-destructive evaluation; additive manufacturing; structural assessment

Special Issue Information

Dear Colleagues,

The growing demand for new technologies, in which cost reduction and energy efficiency are paramount, requires the search for multifunctional design solutions. These solutions need to combine various properties such as lightness, rigidity, and the ability to absorb thermal energy or impact, while being viable from a manufacturing point of view. In this sense, additive manufacturing (AM) offers countless benefits over conventional manufacturing methods, expanding the horizons of component design with high geometric complexity and the use of a wide range of different materials. This new era of digital manufacturing has radically transformed how objects are designed and produced, reaching sectors such as the aerospace, automotive, and biomedical industry, which have greatly benefited from these technological advances.

The key to guaranteeing that manufactured elements can respond to their performance lies in the optimization of printing parameters. To cite an example, the handling of the filling density of the printed parts, which allows for a significant reduction in weight and savings in material, is postulated as one of the most significant competitive advantages of additive manufacturing, as opposed to the limitations in mechanical behavior induced by the heterogeneity and anisotropy. These topics are at the core of the research that the AM community is carrying out at the moment, as they are barriers to the complete transfer of these technologies to the industrial sector.

For this reason, this Special Issue compiles the results of the latest studies and analyses of the mechanical behavior of polymeric parts obtained through additive manufacturing. The studies presented will provide the scientific community with relevant information to better manage printing parameters and to optimize the response of printed polymeric parts to the imposed loads.

It is our pleasure to invite you to submit a manuscript for this Special Issue. Full papers, communications, and reviews are all welcome.

Dr. Giovanni Gómez-Gras
Dr. Marco A. Pérez
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

additive manufacturing
mechanical behavior and characterization
numerical simulation
fused deposition modeling
material jetting manufacturing
selective laser sintering
multi jet fusion manufacturing
stereolithography manufacturing
photopolymerization manufacturing
3D/4D printing

Benefits of Publishing in a Special Issue

Ease of navigation: Grouping papers by topic helps scholars navigate broad scope journals more efficiently.
Greater discoverability: Special Issues support the reach and impact of scientific research. Articles in Special Issues are more discoverable and cited more frequently.
Expansion of research network: Special Issues facilitate connections among authors, fostering scientific collaborations.
External promotion: Articles in Special Issues are often promoted through the journal's social media, increasing their visibility.
e-Book format: Special Issues with more than 10 articles can be published as dedicated e-books, ensuring wide and rapid dissemination.

Further information on MDPI's Special Issue polices can be found here.

Published Papers (14 papers)

Download All Papers

Order results

Result details

Show export options Show export options

Select all

Export citation of selected articles as:

Research

Jump to: Review

19 pages, 6787 KiB

Open AccessArticle

Investigating the Feasibility of Processing Activated Carbon/UHMWPE Polymer Composite Using Laser Powder Bed Fusion

by Yas Khalil, Neil Hopkinson, Adam J. Kowalski and John Patrick A. Fairclough

Polymers 2022, 14(16), 3320; https://doi.org/10.3390/polym14163320 - 15 Aug 2022

Cited by 4 | Viewed by 2174

Abstract

Activated Carbon (AC) is widely available at a relatively low cost, has a high porosity and is commonly used as a filter material for a range of applications. However, it is a brittle and friable material. Ultra-High Molecular Weight Polyethylene (UHMWPE) polymer is a tough engineering plastic that has been used as a binder. The traditional method used in manufacturing AC/UHMWPE filters involves compressing AC/UHMWPE composite powder during heating in a mould. This process compresses the particles together and the materials undergo sintering. This process results in a low pore interconnectivity, which has a considerable impact on the filter’s efficiency. Selective Laser Sintering is a laser powder bed fusion additive manufacturing technique for polymers. This has a number of advantages compared to the conventional technique and produces a porous structure with improved filtration efficiency. We propose that this is due to the greater pore interconnectivity. In this work, AC/UHMWPE powdered composites were prepared with different AC and UHMWPE ratios. The structure and properties of the AC/UHMWPE composite were investigated and characterised to assess their suitability for selective laser sintering. Particle size and morphology analysis were conducted, as well as density measurements, powder flow, thermal analysis, and crystallinity measurements. The results reveal that the addition of AC improves the UHMWPE flow. The thermal analysis results show that the intrinsic thermal properties of UHMWPE powder are not significantly affected by the introduction of activated carbon. However, thermal gravimetric analysis revealed that the onset of mass loss is considerably shifted (20 °C) to higher temperatures for the AC/UHMWPE composites, which is favourable for laser sintering. Additionally, the change in the composition ratio of untreated composite does not have a significant effect on the degree of crystallinity. Laser-sintered AC/UHMWPE parts were successfully manufactured using a commercial laser-sintering machine. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Figure 1

12 pages, 416 KiB

Open AccessArticle

Viscoelastic Characterization of a Thermoplastic Elastomer Processed through Material Extrusion

by Bàrbara Adrover-Monserrat, Silvia García-Vilana, David Sánchez-Molina, Jordi Llumà, Ramón Jerez-Mesa and J. Antonio Travieso-Rodriguez

Polymers 2022, 14(14), 2914; https://doi.org/10.3390/polym14142914 - 18 Jul 2022

Cited by 2 | Viewed by 2101

Abstract

Objective. We aim to characterize the viscoelastic behavior of Polyether-Block-Amide (PEBA 90A), provide reference values for the parameters of a constitutive model for the simulation of mechanical behaviors, and paying attention to the influence of the manufacturing conditions. Methods. Uniaxial relaxation tests of filaments of PEBA were used to determine the values of the parameters of a Prony series for a Quasi-Linear Visco-Elastic (QLVE) model. Additional, fast cyclic loading tests were used to corroborate the adequacy of the model under different test criteria in a second test situation. Results. The QLVE model predicts the results of the relaxation tests very accurately. In addition, the behavior inferred from this model fits very well with the measurements of fast cyclic loading tests. The viscoelastic behavior of PEBA under small strain polymer fits very well to a six-parameter QLVE model. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Figure 1

24 pages, 5415 KiB

Open AccessArticle

Photoinitiator Selection and Concentration in Photopolymer Formulations towards Large-Format Additive Manufacturing

by Alex Stiles, Thomas-Allan Tison, Liam Pruitt and Uday Vaidya

Polymers 2022, 14(13), 2708; https://doi.org/10.3390/polym14132708 - 1 Jul 2022

Cited by 10 | Viewed by 3889

Abstract

Photopolymers are an attractive option for large-format additive manufacturing (LFAM), because they can be formulated from structural thermosets and cure rapidly in ambient conditions under low-energy ultraviolet light-emitting diode (UV LED) lamps. Photopolymer cure is strongly influenced by the depth penetration of UV light, which can be limited in the 2–4 mm layer thicknesses typical of LFAM. Photoinitiator (PI) systems that exhibit photobleaching have proven useful in thick-section cure applications, because they generate a photoinitiation wavefront, but this effect is time-dependent. This study investigates the light transmission and through-thickness cure behavior in (meth)acrylate photopolymer formulations with the photobleaching initiator bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (BAPO). Utilizing an optical model developed by Kenning et al., lower concentrations (0.1 wt% to 0.5 wt%) of BAPO were predicted to yield rapid onset of photoinitiation. In situ cure measurements under continuous UV LED irradiation of 380 mW/cm² showed that a 0.1 wt% concentration of BAPO achieved peak polymerization rate within 2.5 s at a 3-mm depth. With only 1 s of irradiation at 1.7 W/cm² intensity, the 0.1 wt% BAPO formulation also achieved the highest level of cure of the formulas tested. For an irradiation dose of 5.5 J/cm² at a duration of 3.7 s, cured polymer specimens achieved a flexural strength of 108 MPa and a flexural modulus of 3.1 GPa. This study demonstrates the utility of optical modeling as a potential screening tool for new photopolymer formulations, primarily in identifying an upper limit to PI concentration for the desired cure depth. The results also show that photobleaching provides only a limited benefit for LFAM applications with short (1.0 s to 3.7 s) UV irradiation times and indicate that excess PI concentration can inhibit light transmission even under extended irradiation times up to 60 s. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Graphical abstract

19 pages, 9593 KiB

Open AccessArticle

Influence of Atmospheric Conditions on Mechanical Properties of Polyamide with Different Content of Recycled Material in Selective Laser Sintering

by Ana Pilipović, Petar Ilinčić, Ante Bakić and Janoš Kodvanj

Polymers 2022, 14(12), 2355; https://doi.org/10.3390/polym14122355 - 10 Jun 2022

Cited by 5 | Viewed by 1923

Abstract

The price of material is an important factor when selecting the additive polymer procedure. In selective laser sintering (SLS), the price can be reduced by the recycling of material, i.e., with different shares of original and recycled material, as well as by the orientation of the product during manufacturing. Numerous tests warn that orientation in the direction of z axis should be as low as possible to reduce the total price of the product. The product also has to satisfy the influence of atmospheric conditions to which it is exposed during its lifetime, i.e., UV radiation and humid environment. UV light, with sun being its most common source, and average humidity in different parts of the world can be approximately from 20% to 90%, depending on time, day and geographic location. In this work, the test specimens have been made of original, mixed and 100% recycled material and then exposed to the influences of UV radiation and water absorption. After having been exposed to atmospheric conditions for a longer time, the mechanical properties of the polyamide products made by selective laser sintering were tested. The results show that exposure to UV radiation reduces tensile elongation at all ratios of recycled material and orientation of 70–90% except in the z direction, while in flexural deformation it is the other way around. The effect of water was observed only between the 7th–14th day of absorption with a decrease in strength until the deformation did not change. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Figure 1

17 pages, 3340 KiB

Open AccessArticle

Design for 3D Printed Tools: Mechanical Material Properties for Direct Polymer Additive Tooling

by Peter Frohn-Sörensen, Michael Geueke, Bernd Engel, Bernd Löffler, Philipp Bickendorf, Arian Asimi, Georg Bergweiler and Günther Schuh

Polymers 2022, 14(9), 1694; https://doi.org/10.3390/polym14091694 - 21 Apr 2022

Cited by 16 | Viewed by 3063

Abstract

In relation to the fourth industrial revolution, traditional manufacturing methods cannot serve the flexibility demands related to mass customization and small series production. Rapid tooling provided by generative manufacturing has been suggested recently in the context of metal forming. Due to the high loads applied during processes to such tooling, a purposeful mechanical description of the additively manufactured (AM) materials is crucial. Until now, a comprehensive characterization approach for AM polymers is required to allow a sophisticated layout of rapid tooling. In detail, information on compressive and flexural mechanical properties of solid infilled materials made by additive manufacturing are sparsely available. These elementary mechanical properties are evaluated in the present study. They result from material specimens additively manufactured in the fused filament fabrication (FFF) process. The design of the experiments reveals significant influences of the polymer and the layer height on the resulting flexural and compressive strength and modulus as well as density, hardness, and surface roughness. As a case study, these findings are applied to a cup drawing operation based on the strongest and weakest material and parameter combination. The obtained data and results are intended to guide future applications of direct polymer additive tooling. The presented case study illustrates such an application and shows the range of manufacturing quality achievable within the materials and user settings for 3D printing. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Figure 1

13 pages, 8316 KiB

Open AccessArticle

Study of the Influence of the Manufacturing Parameters on Tensile Properties of Thermoplastic Elastomers

by Bàrbara Adrover-Monserrat, Jordi Llumà, Ramón Jerez-Mesa and J. Antonio Travieso-Rodriguez

Polymers 2022, 14(3), 576; https://doi.org/10.3390/polym14030576 - 31 Jan 2022

Cited by 14 | Viewed by 2937

Abstract

Additive manufacturing (AM) has increased its field of application, not only for prototypes but also for final parts. Therefore, the need to study new materials is currently growing. This paper aims to study the effect of the printing parameters used in two different thermoplastic elastomers (PEBA 90A and TPU 98A) subjected to tensile tests, evaluating a competent alternative to the currently most used 3D printed materials. To achieve it, a full factorial design experiment is applied to analyze the influence on the tensile responses of two printing parameters: the layer height and the fill density. In addition, an analysis of variance (ANOVA) is used to describe the relations among the parameters and the mechanical responses obtained. Moreover, assessment of damping properties was done. Results show that each thermoplastic elastomer should be studied separately, although the proposed methodology can be used for each material independently of their nature. Finally, a correlation between the printing parameters and the mechanical behavior of TPU 98A and PEBA 90A was found: the layer height and the infill are statistically influential parameters for both materials. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Figure 1

13 pages, 36423 KiB

Open AccessArticle

Accelerated Aging Effect on Mechanical Properties of Common 3D-Printing Polymers

by Catalin Gheorghe Amza, Aurelian Zapciu, Florin Baciu, Mihai Ion Vasile and Adrian Ionut Nicoara

Polymers 2021, 13(23), 4132; https://doi.org/10.3390/polym13234132 - 26 Nov 2021

Cited by 25 | Viewed by 3300

Abstract

In outdoor environments, the action of the Sun through its ultraviolet radiation has a degrading effect on most materials, with polymers being among those affected. In the past few years, 3D printing has seen an increased usage in fabricating parts for functional applications, including parts destined for outdoor use. This paper analyzes the effect of accelerated aging through prolonged exposure to UV-B on the mechanical properties of parts 3D printed from the commonly used polymers polylactic acid (PLA) and polyethylene terephthalate–glycol (PETG). Samples 3D printed from these materials went through a dry 24 h UV-B exposure aging treatment and were then tested against a control group for changes in mechanical properties. Both the tensile and compressive strengths were determined, as well as changes in material creep characteristics. After irradiation, PLA and PETG parts saw significant decreases in both tensile strength (PLA: −5.3%; PETG: −36%) and compression strength (PLA: −6.3%; PETG: −38.3%). Part stiffness did not change significantly following the UV-B exposure and creep behavior was closely connected to the decrease in mechanical properties. A scanning electron microscopy (SEM) fractographic analysis was carried out to better understand the failure mechanism and material structural changes in tensile loaded, accelerated aged parts. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Graphical abstract

17 pages, 5631 KiB

Open AccessArticle

Mechanical Performance of 3D-Printed Biocompatible Polycarbonate for Biomechanical Applications

by Giovanni Gómez-Gras, Manuel D. Abad and Marco A. Pérez

Polymers 2021, 13(21), 3669; https://doi.org/10.3390/polym13213669 - 25 Oct 2021

Cited by 13 | Viewed by 3003

Abstract

Additive manufacturing has experienced remarkable growth in recent years due to the customisation, precision, and cost savings compared to conventional manufacturing techniques. In parallel, materials with great potential have been developed, such as PC-ISO polycarbonate, which has biocompatibility certifications for use in the biomedical industry. However, many of these synthetic materials are not capable of meeting the mechanical stresses to which the biological structure of the human body is naturally subjected. In this study, an exhaustive characterisation of the PC-ISO was carried out, including an investigation on the influence of the printing parameters by fused filament fabrication on its mechanical behaviour. It was found that the effect of the combination of the printing parameters does not have a notable impact on the mass, cost, and manufacturing time of the specimens; however, it is relevant when determining the tensile, bending, shear, impact, and fatigue strengths. The best combinations for its application in biomechanics are proposed, and the need to combine PC-ISO with other materials to achieve the necessary strengths for functioning as a bone scaffold is demonstrated. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Figure 1

26 pages, 10344 KiB

Open AccessArticle

3D Printing of Thermoplastic Elastomers: Role of the Chemical Composition and Printing Parameters in the Production of Parts with Controlled Energy Absorption and Damping Capacity

by Marina León-Calero, Sara Catherine Reyburn Valés, Ángel Marcos-Fernández and Juan Rodríguez-Hernandez

Polymers 2021, 13(20), 3551; https://doi.org/10.3390/polym13203551 - 15 Oct 2021

Cited by 42 | Viewed by 6265

Abstract

Additive manufacturing (AM) is a disruptive technology that enables one to manufacture complex structures reducing both time and manufacturing cost. Among the materials commonly used for AM, thermoplastic elastomers (TPE) are of high interest due to their energy absorption capacity, energy efficiency, cushion factor or damping capacity. Previous investigations have exclusively focused on the optimization of the printing parameters of commercial TPE filaments and the structures to analyse the mechanical properties of the 3D printed parts. In the present paper, the chemical, thermal and mechanical properties for a wide range of commercial thermoplastic polyurethanes (TPU) filaments were investigated. For this purpose, TGA, DSC, ¹H-NMR and filament tensile strength experiments were carried out in order to determine the materials characteristics. In addition, compression tests have been carried out to tailor the mechanical properties depending on the 3D printing parameters such as: infill density (10, 20, 50, 80 and 100%) and infill pattern (gyroid, honeycomb and grid). The compression tests were also employed to calculate the specific energy absorption (SEA) and specific damping capacity (SDC) of the materials in order to establish the role of the chemical composition and the geometrical characteristics (infill density and type of infill pattern) on the final properties of the printed part. As a result, optimal SEA and SDC performances were obtained for a honeycomb pattern at a 50% of infill density. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Figure 1

19 pages, 7547 KiB

Open AccessArticle

Characterisation and Modelling of PLA Filaments and Evolution with Time

by Jaime Orellana Barrasa, Ana Ferrández-Montero, Begoña Ferrari and José Ygnacio Pastor

Polymers 2021, 13(17), 2899; https://doi.org/10.3390/polym13172899 - 28 Aug 2021

Cited by 18 | Viewed by 3663

Abstract

The properties of polylactic acid (PLA) filaments have not yet been analysed in detail, and they are strongly affected by the extrusion process used in some additive manufacturing systems. Here we present the mechanical, thermal, physical, and fractographical properties of an extruded filament (not the bulk material or scaffolds), the basic building block of any PLA structure printed via material extrusion. This research aims to create a reference point for the modelisation of additively manufactured structures via extrusion processes, as the main building block is characterised in detail for a deep understanding. Furthermore, we investigated the natural ageing (up to one year), the effect of the printing (extruding) temperature (180 and 190 °C), and the effect of the crosshead speed during the tensile tests (10⁻¹ to 10² mm/min) to provide a deeper analysis of the material. The results showed that the material extruded at 190 °C performed better than the material extruded at 180 °C. However, after one hundred days of natural ageing, both materials behaved similarly. This was related to the flow-induced molecular orientation during the extrusion. The crosshead rate produced a logarithmic increase of the mechanical properties, consistent with the Eyring model. Additionally, the ageing produced significant changes in both the elastic modulus and the yield strength: from 2.4 GPa and 40 MPa, in one-day-aged samples, up to 4 GPa and 62 MPa once entirely aged. Finally, it was observed that the glass transition and the enthalpic relaxation increased with ageing, agreeing with the Kohlraushch–William–Watts model. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Graphical abstract

16 pages, 8208 KiB

Open AccessArticle

Effect of Printing Parameters on the Tensile Properties of 3D-Printed Polylactic Acid (PLA) Based on Fused Deposition Modeling

by Ming-Hsien Hsueh, Chao-Jung Lai, Cheng-Feng Chung, Shi-Hao Wang, Wen-Chen Huang, Chieh-Yu Pan, Yu-Shan Zeng and Chia-Hsin Hsieh

Polymers 2021, 13(14), 2387; https://doi.org/10.3390/polym13142387 - 20 Jul 2021

Cited by 50 | Viewed by 5992

Abstract

In order to optimize the efficiency of the Fused deposition modeling (FDM) process, this study used polylactic acid (PLA) material under different parameters (the printing angle and the raster angle) to fabricate specimens and to explore its tensile properties. The effect of the ultraviolet (UV) curing process on PLA materials was also investigated. The results showed that the printing and raster angles have a high impact on the tensile properties of PLA materials. The UV curing process enhanced the brittleness and reduced the elongation of PLA material. Different effects were observed on tensile strength and modulus of specimens printed with different parameters after UV curing. The above results will be a great help for researchers who are working to achieve sustainability of PLA materials and FDM technology. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Figure 1

18 pages, 6874 KiB

Open AccessArticle

Experimental, Computational, and Dimensional Analysis of the Mechanical Performance of Fused Filament Fabrication Parts

by Iván Rivet, Narges Dialami, Miguel Cervera, Michele Chiumenti, Guillermo Reyes and Marco A. Pérez

Polymers 2021, 13(11), 1766; https://doi.org/10.3390/polym13111766 - 27 May 2021

Cited by 17 | Viewed by 3706

Abstract

Process parameters in Additive Manufacturing (AM) are key factors in the mechanical performance of 3D-printed parts. In order to study their effect, a three-zone model based on the printing pattern was developed. This modelization distinguished three different zones of the 3D-printed part, namely cover, contour, and inner; each zone was treated as a different material. The cover and contour zones were characterized via uniaxial tensile tests and the inner zones via computational homogenization. The model was then validated by means of bending tests and their corresponding computational simulations. To reduce the number of required characterization experiments, a relationship between the raw and 3D-printed material was established by dimensional analysis. This allowed describing the mechanical properties of the printed part with a reduced set of the most influential non-dimensional relationships. The influence on the performance of the parts of inter-layer adhesion was also addressed in this work via the characterization of samples made of Polycarbonate Acrylonitrile Butadiene Styrene (ABS/PC), a polymeric material well known for its poor adhesion strength. It was concluded that by using this approach, the number of required testing configurations could be reduced by two thirds, which implies considerable cost savings. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Figure 1

16 pages, 20046 KiB

Open AccessArticle

Experimental Characterization Framework for SLA Additive Manufacturing Materials

by Jordi Martín-Montal, Jesus Pernas-Sánchez and David Varas

Polymers 2021, 13(7), 1147; https://doi.org/10.3390/polym13071147 - 2 Apr 2021

Cited by 41 | Viewed by 4843

Abstract

Additive manufacturing (AM) is driving a change in the industry not only regarding prototyping but due to the ease of including printed parts in final designs. Engineers and designers can go deeper into optimization and improvements of their designs without drawbacks of long manufacturing times. However, some drawbacks such as the limited available materials or uncertainty about mechanical properties and anisotropic behavior of 3D printed parts prevent use in large-scale production. To gain knowledge and confidence about printed materials it is necessary to know how they behave under different stress states and strain-rate regimes, and how some of the printing parameters may affect them. The present work proposes an experimental methodology framework to study and characterize materials printed by stereolithography (SLA) to clarify certain aspects that must be taken into account to broaden the use of this kind of material. To this end, tensile and compression tests at different strain rates were carried out. To study the influence of certain printing parameters on the printed material behavior, samples with different printing angles (

θ

= [0–90]) and different printing resolution (layer height of 50 and 100 µm) were tested. In addition, the effects of curing time and temperature were also studied. The testing specimens were manufactured in the non-professional SLA machine Form 2 from Formlabs^® using resin called Durable. Nevertheless, the proposed experimental methodology could be extended to any other resin. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Graphical abstract

Review

Jump to: Research

35 pages, 7047 KiB

Open AccessReview

Optimisation of Strength Properties of FDM Printed Parts—A Critical Review

by Daniyar Syrlybayev, Beibit Zharylkassyn, Aidana Seisekulova, Mustakhim Akhmetov, Asma Perveen and Didier Talamona

Polymers 2021, 13(10), 1587; https://doi.org/10.3390/polym13101587 - 14 May 2021

Cited by 164 | Viewed by 12085

Abstract

Additive Manufacturing is currently growing fast, especially fused deposition modeling (FDM), also known as fused filament fabrication (FFF). When manufacturing parts use FDM, there are two key parameters—strength of the part and dimensional accuracy—that need to be considered. Although FDM is a popular technology for fabricating prototypes with complex geometry and other part product with reduced cycle time, it is also limited by several drawbacks including inadequate mechanical properties and reduced dimensional accuracy. It is evident that part qualities are greatly influenced by the various process parameters, therefore an extensive review of the effects of the following process parameters was carried out: infill density, infill patterns, extrusion temperature, layer thickness, nozzle diameter, raster angle and build orientation on the mechanical properties. It was found from the literature that layer thickness is the most important factor among the studied ones. Although manipulation of process parameters makes significant differences in the quality and mechanical properties of the printed part, the ideal combination of parameters is challenging to achieve. Hence, this study also includes the influence of pre-processing of the printed part to improve the part strength and new research trends such as, vacuum-assisted FDM that has shown to improve the quality of the printing due to improved bonding between the layers. Advances in materials and technologies that are currently under development are presented. For example, the pre-deposition heating method, using an IR lamp of other technologies, shows a positive impact on the mechanical properties of the printed parts. Full article

(This article belongs to the Special Issue Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing)

► Show Figures

Journal Menu

Journal Browser

Mechanical Performance of Polymeric Parts Obtained by Additive Manufacturing

Share This Special Issue

Special Issue Editors

Special Issue Information

Keywords

Benefits of Publishing in a Special Issue

Published Papers (14 papers)

Research

Review

Further Information

Guidelines

MDPI Initiatives

Follow MDPI