Materials for 3D Printing

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Materials Science and Engineering".

Deadline for manuscript submissions: closed (31 March 2017) | Viewed by 82352

Special Issue Editor

Department of Chemical Engineering, Katholieke Universiteit Leuven, Celestijnenlaan 200f-box 2424, 3001 Leuven, Belgium
Interests: applied materials; rheology; polymer processing; additive manufacturing

Special Issue Information

Dear Colleagues,

Additive manufacturing, commonly referred to as 3D-printing, has seen a tremendous popularity in the last few years. The different techniques were invented in the eighties and since then, most of the research efforts have gone into machine development. However, recently, it has been realized that also the material aspect plays a crucial role in making performant 3D-printed parts. Hence, designing new materials or adapting existing materials (being polymers, ceramics, or metals) to a specific additive manufacturing technology is key in a successful and sustainable growth of 3D-printing. This Special Issue will address present advances and challenges in the material development in this promising manufacturing method.

Prof. Dr. Peter Van Puyvelde
Guest Editor

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Keywords

  • 3D printing
  • fused deposition modeling
  • selective laser sintering
  • stereolithography
  • material testing

Published Papers (10 papers)

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4407 KiB  
Article
Impact of the Fused Deposition (FDM) Printing Process on Polylactic Acid (PLA) Chemistry and Structure
by Michael Arthur Cuiffo, Jeffrey Snyder, Alicia M. Elliott, Nicholas Romero, Sandhiya Kannan and Gary P. Halada
Appl. Sci. 2017, 7(6), 579; https://0-doi-org.brum.beds.ac.uk/10.3390/app7060579 - 04 Jun 2017
Cited by 173 | Viewed by 15218
Abstract
Polylactic acid (PLA) is an organic polymer commonly used in fused deposition (FDM) printing and biomedical scaffolding that is biocompatible and immunologically inert. However, variations in source material quality and chemistry make it necessary to characterize the filament and determine potential changes in [...] Read more.
Polylactic acid (PLA) is an organic polymer commonly used in fused deposition (FDM) printing and biomedical scaffolding that is biocompatible and immunologically inert. However, variations in source material quality and chemistry make it necessary to characterize the filament and determine potential changes in chemistry occurring as a result of the FDM process. We used several spectroscopic techniques, including laser confocal microscopy, Fourier transform infrared (FTIR) spectroscopy and photoacousitc FTIR spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) in order to characterize both the bulk and surface chemistry of the source material and printed samples. Scanning electron microscopy (SEM) and differential scanning calorimetry (DSC) were used to characterize morphology, cold crystallinity, and the glass transition and melting temperatures following printing. Analysis revealed calcium carbonate-based additives which were reacted with organic ligands and potentially trace metal impurities, both before and following printing. These additives became concentrated in voids in the printed structure. This finding is important for biomedical applications as carbonate will impact subsequent cell growth on printed tissue scaffolds. Results of chemical analysis also provided evidence of the hygroscopic nature of the source material and oxidation of the printed surface, and SEM imaging revealed micro- and submicron-scale roughness that will also impact potential applications. Full article
(This article belongs to the Special Issue Materials for 3D Printing)
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7529 KiB  
Article
Influence of the Origin of Polyamide 12 Powder on the Laser Sintering Process and Laser Sintered Parts
by Manfred Schmid, Rob Kleijnen, Marc Vetterli and Konrad Wegener
Appl. Sci. 2017, 7(5), 462; https://0-doi-org.brum.beds.ac.uk/10.3390/app7050462 - 30 Apr 2017
Cited by 58 | Viewed by 8117
Abstract
Different features of polymer powders influence the process of laser sintering (LS) and the properties of LS-parts to a great extent. This study investigates important aspects of the “powder/process/part”-property relationships by comparing two polyamide 12 (PA12) powders commercially available for LS, with pronounced [...] Read more.
Different features of polymer powders influence the process of laser sintering (LS) and the properties of LS-parts to a great extent. This study investigates important aspects of the “powder/process/part”-property relationships by comparing two polyamide 12 (PA12) powders commercially available for LS, with pronounced powder characteristic differences (Duraform® PA and Orgasol® Invent Smooth). Due to the fact that the primary influence factor on polymer behaviour, the chemical structure of the polymer chain, is identical in this case, the impacts resulting from powder distribution, particle shape, thermal behaviour, and crystalline and molecular structure, can be studied in detail. It was shown that although both systems are PA12, completely different processing conditions must be applied to accomplish high-resolution parts. The reason for this was discovered by the different thermal behaviour based on the powder production and the resulting crystalline structure. Moreover, the parts built from Orgasol® Invent Smooth unveil mechanical properties with pronounced anisotropy, caused from the high melt viscosity and termination of polymer chains. Further differences are seen in relation to the powder characteristics and other significant correlations could be revealed. For example, the study demonstrated how the particle morphology and shape impact the surface roughness of the parts. Full article
(This article belongs to the Special Issue Materials for 3D Printing)
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5285 KiB  
Article
Dense Pure Tungsten Fabricated by Selective Laser Melting
by Dianzheng Wang, Chenfan Yu, Xin Zhou, Jing Ma, Wei Liu and Zhijian Shen
Appl. Sci. 2017, 7(4), 430; https://0-doi-org.brum.beds.ac.uk/10.3390/app7040430 - 23 Apr 2017
Cited by 84 | Viewed by 9470
Abstract
Additive manufacturing using tungsten, a brittle material, is difficult because of its high melting point, thermal conductivity, and oxidation tendency. In this study, pure tungsten parts with densities of up to 18.53 g/cm3 (i.e., 96.0% of the theoretical density) were fabricated by selective [...] Read more.
Additive manufacturing using tungsten, a brittle material, is difficult because of its high melting point, thermal conductivity, and oxidation tendency. In this study, pure tungsten parts with densities of up to 18.53 g/cm3 (i.e., 96.0% of the theoretical density) were fabricated by selective laser melting. In order to minimize balling effects, the raw polyhedral tungsten powders underwent a spheroidization process before laser consolidation. Compared with polyhedral powders, the spherical powders showed increased laser absorptivity and packing density, which helped in the formation of a continuous molten track and promoted densification. Full article
(This article belongs to the Special Issue Materials for 3D Printing)
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3355 KiB  
Article
Mechanically Strong CaSiO3 Scaffolds Incorporating B2O3-ZnO Liquid Phase
by Cijun Shuai, Songlin Duan, Dan Gao, Ping Wu, Chengde Gao, Youwen Yang, Long Liu, Fulai Yuan, Sheng Yang and Pei Feng
Appl. Sci. 2017, 7(4), 387; https://0-doi-org.brum.beds.ac.uk/10.3390/app7040387 - 13 Apr 2017
Cited by 3 | Viewed by 3999
Abstract
Calcium silicate (CaSiO3) scaffolds were reinforced by introducing liquid phase. The liquid phase was made of B2O3 and ZnO. The fracture toughness and compressive strength increased by 48% and 141%, respectively, compared with those of the scaffolds without [...] Read more.
Calcium silicate (CaSiO3) scaffolds were reinforced by introducing liquid phase. The liquid phase was made of B2O3 and ZnO. The fracture toughness and compressive strength increased by 48% and 141%, respectively, compared with those of the scaffolds without the liquid phase. This was attributed to the enhanced densification, the elongated grains pull-out and the cracks bridging. In addition, because of its increasing mechanical properties, the fracture model of the cleavage fracture was more beneficial than the intergranular fracture. The mechanical properties of the scaffolds with the liquid phase could be steadily maintained and then they decreased slowly when immersed in simulated body fluid (SBF). Meanwhile, the hydroxyapatite (HAp) generated on their surfaces. In addition, the scaffolds possessed favorable biocompatibility and could promote cell proliferation. These results demonstrated that the scaffolds with B2O3-ZnO liquid phase are a promising substitute for bone repair applications. Full article
(This article belongs to the Special Issue Materials for 3D Printing)
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1356 KiB  
Article
Novel Composite Powders with Uniform TiB2 Nano-Particle Distribution for 3D Printing
by Mengxing Chen, Xiaopeng Li, Gang Ji, Yi Wu, Zhe Chen, Wouter Baekelant, Kim Vanmeensel, Haowei Wang and Jean-Pierre Kruth
Appl. Sci. 2017, 7(3), 250; https://0-doi-org.brum.beds.ac.uk/10.3390/app7030250 - 06 Mar 2017
Cited by 51 | Viewed by 8268
Abstract
It is reported that the ductility and strength of a metal matrix composite could be concurrently improved if the reinforcing particles were of the size of nanometers and distributed uniformly. In this paper, we revealed that gas atomization solidification could effectively disperse TiB [...] Read more.
It is reported that the ductility and strength of a metal matrix composite could be concurrently improved if the reinforcing particles were of the size of nanometers and distributed uniformly. In this paper, we revealed that gas atomization solidification could effectively disperse TiB2 nanoparticles in the Al alloy matrix due to its fast cooling rate and the coherent orientation relationship between TiB2 particles and α-Al. Besides, nano-TiB2 led to refined equiaxed grain structures. Furthermore, the composite powders with uniformly embedded nano-TiB2 showed improved laser absorptivity. The novel composite powders are well suited for selective laser melting. Full article
(This article belongs to the Special Issue Materials for 3D Printing)
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7166 KiB  
Article
Microstructure and Mechanical Properties of Ti-6Al-4V Fabricated by Vertical Wire Feeding with Axisymmetric Multi-Laser Source
by Jie Fu, Lin Gong, Yifei Zhang, Qianru Wu, Xuezhi Shi, Junchao Chang and Jiping Lu
Appl. Sci. 2017, 7(3), 227; https://0-doi-org.brum.beds.ac.uk/10.3390/app7030227 - 28 Feb 2017
Cited by 19 | Viewed by 7291
Abstract
Vertical wire feeding with an axisymmetric multi-laser source (feeding the wire vertically into the molten pool) has exhibited great advantages over LAM (laser additive manufacturing) with paraxial wire feeding, which has an anisotropic forming problem in different scanning directions. This paper investigates the [...] Read more.
Vertical wire feeding with an axisymmetric multi-laser source (feeding the wire vertically into the molten pool) has exhibited great advantages over LAM (laser additive manufacturing) with paraxial wire feeding, which has an anisotropic forming problem in different scanning directions. This paper investigates the forming ability of vertical wire feeding with an axisymmetric multi-laser source, and the microstructure and mechanical properties of the fabricated components. It has been found that vertical wire feeding with an axisymmetric multi-laser source has a strong forming ability with no anisotropic forming problem when fabricating the complex parts in a three-axis machine tool. Most of the grains in the samples are equiaxed grains, and a small amount of short columnar grains exist which are parallel to each other. The microstructure of the fabricated samples exhibits a fine basket-weave structure and martensite due to the fast cooling rate which was caused by the small size of the molten pool and the additional heat dissipation from the feeding wire. The static tensile test shows that the average ultimate tensile strength is 1140 MPa in the scanning direction and 1115 MPa in the building direction, and the average elongation is about 6% in both directions. Full article
(This article belongs to the Special Issue Materials for 3D Printing)
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3273 KiB  
Article
Development of a Robotic Arm Based Hydrogel Additive Manufacturing System for In-Situ Printing
by Xiao Li, Qin Lian, Dichen Li, Hua Xin and Shuhai Jia
Appl. Sci. 2017, 7(1), 73; https://0-doi-org.brum.beds.ac.uk/10.3390/app7010073 - 11 Jan 2017
Cited by 44 | Viewed by 7764
Abstract
In-situ printing is a promising injury repair technique that can be directly applied during surgical operations. This paper features a potential in-situ printing platform based on a small-scale robotic arm with a micro-sized dispenser valve. A double-light-source curing method was applied to print [...] Read more.
In-situ printing is a promising injury repair technique that can be directly applied during surgical operations. This paper features a potential in-situ printing platform based on a small-scale robotic arm with a micro-sized dispenser valve. A double-light-source curing method was applied to print poly(ethylene glycol) diacrylate (PEGDA) with a 20% (weight/volume) ratio and the entire process was controlled automatically by a computer interface where droplet diameter, curing time, mechanical properties were measured and essential printing parameters (e.g., nozzle velocity, nozzle frequency) were determined. Three different two-dimensional (2D) plane models (namely, square, circular, and heart-shaped) were printed during initial printing trials. The feasibility study of in-situ printing on curved surfaces was tested using a three-dimensional (3D) printed defect model. The defect was successfully filled using both parallel and ring printing paths. In conclusion, the robotic arm printing platform and its forming method can achieve a rapid curing of PEGDA hydrogel on a curved surface and has the potential to be applied to in-situ printing. Full article
(This article belongs to the Special Issue Materials for 3D Printing)
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3633 KiB  
Article
The Influence of Process Parameters on the Surface Roughness of a 3D-Printed Co–Cr Dental Alloy Produced via Selective Laser Melting
by Min-Ho Hong, Bong Ki Min and Tae-Yub Kwon
Appl. Sci. 2016, 6(12), 401; https://0-doi-org.brum.beds.ac.uk/10.3390/app6120401 - 01 Dec 2016
Cited by 58 | Viewed by 8748
Abstract
Selective laser melting (SLM), used to fabricate metallic objects with high geometrical complexity, is currently of increasing interest to the fields of medicine and dentistry. SLM-fabricated products should have highly smooth surfaces to minimize the use of post-processing procedures such as finishing and [...] Read more.
Selective laser melting (SLM), used to fabricate metallic objects with high geometrical complexity, is currently of increasing interest to the fields of medicine and dentistry. SLM-fabricated products should have highly smooth surfaces to minimize the use of post-processing procedures such as finishing and polishing. This study investigated the effect of various laser process parameters (laser power, scan rate, and scan-line spacing) on the surface roughness of a Co–Cr dental alloy that was three-dimensionally (3D) constructed via SLM. Initially, a single-line formation test was used to determine the optimal laser power (200 W) and scan rate (128.6 mm/s) that resulted in beads with an optimal profile. During subsequent multi-layer formation tests, the 3D Co–Cr body with the smoothest surface was produced using a scan-line spacing of 100 μm. The findings of this study show that laser process parameters have crucial effects on the surface quality of SLM-fabricated Co–Cr dental alloys. Full article
(This article belongs to the Special Issue Materials for 3D Printing)
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2901 KiB  
Concept Paper
Sintering of Two Viscoelastic Particles: A Computational Approach
by Caroline Balemans, Martien A. Hulsen and Patrick D. Anderson
Appl. Sci. 2017, 7(5), 516; https://0-doi-org.brum.beds.ac.uk/10.3390/app7050516 - 16 May 2017
Cited by 18 | Viewed by 4968
Abstract
Selective laser sintering (SLS) is a high-resolution additive manufacturing fabrication technique. To fully understand the process, we developed a computational model, using the finite element method, to solve the flow problem of sintering two viscoelastic particles. The flow is assumed to be isothermal [...] Read more.
Selective laser sintering (SLS) is a high-resolution additive manufacturing fabrication technique. To fully understand the process, we developed a computational model, using the finite element method, to solve the flow problem of sintering two viscoelastic particles. The flow is assumed to be isothermal and the particles to be in a liquid state, where their rheology is described using the Giesekus and XPP constitutive models. In this work, we assess the parameters that define this problem, such as the initial geometry, the Deborah number and other dimensionless parameters present in the rheological models. In particular, the conformation tensor is considered, which is a measure for the polymeric strain and plays an important role in the crystallization kinetics of semicrystalline polymers like polyamide 12, usually used in SLS. Full article
(This article belongs to the Special Issue Materials for 3D Printing)
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10750 KiB  
Letter
Residual Stress, Defects and Grain Morphology of Ti-6Al-4V Alloy Produced by Ultrasonic Impact Treatment Assisted Selective Laser Melting
by Meixia Zhang, Changmeng Liu, Xuezhi Shi, Xianping Chen, Cheng Chen, Jianhua Zuo, Jiping Lu and Shuyuan Ma
Appl. Sci. 2016, 6(11), 304; https://0-doi-org.brum.beds.ac.uk/10.3390/app6110304 - 25 Oct 2016
Cited by 57 | Viewed by 7629
Abstract
For large-scale selective laser melting (SLM) additive manufacturing technology, three main problems severely restrict its development and application, namely the residual stress, defects, and columnar grains with anisotropy. To overcome these problems, a new method is proposed by combining SLM with ultrasonic impact [...] Read more.
For large-scale selective laser melting (SLM) additive manufacturing technology, three main problems severely restrict its development and application, namely the residual stress, defects, and columnar grains with anisotropy. To overcome these problems, a new method is proposed by combining SLM with ultrasonic impact treatment (UIT) technique. This study explores the feasibility of UIT assisted SLM, as well as the effect of UIT on the residual stress, defects and β grains of Ti-6Al-4V alloy sample. The results indicate that after the application of UIT during SLM, residual stress can be largely reduced and defects can be hammered flat and even eliminated. Meanwhile, the epitaxial growth of columnar grains is prevented, and fine equiaxed grains are formed due to plastic deformation and recrystallization. Full article
(This article belongs to the Special Issue Materials for 3D Printing)
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