Recent Development in Post-processing for Additive Manufacturing

A special issue of Coatings (ISSN 2079-6412). This special issue belongs to the section "Surface Characterization, Deposition and Modification".

Deadline for manuscript submissions: 31 October 2024 | Viewed by 9029

Special Issue Editors

School of Mechanical Engineering and Automation, Harbin Institute of Technology, Shenzhen, China
Interests: additive manufacturing; post-processing; machining; advanced manufacturing; hybrid manufacturing; multi-material

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Guest Editor
Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore
Interests: hybrid and additive manufacturing; post-processing; ultraprecision machining
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The unique manufacturing method of layer-by-layer manufacturing enables additive manufacturing (AM) technology to outperform traditional subtractive manufacturing process for customized products, geometrically complex parts, and near-net-shape rapid manufacturing. Therefore, this technology has been attracting great attention. To date, AM technology has been extended to automotive, aerospace, moulding, medical, and biomedical industries, among others. However, the application of AM is also facing severe challenges, such as support, the staircase effect, surface adhesion, geometric size deviation, microstructure inhomogeneity, performance anisotropy, and dissimilar material interface transition. In addition, the internal and external features of complex parts make traditional surface treatment processes no longer suitable. The surface and subsurface of the additively manufactured parts exhibit unique performance characteristics, which requires new surface treatment processes to achieve support structure removal, surface performance improvement, tissue performance regulation, dimensional accuracy improvement and surface finish improvement. Based on the AM process’s characteristics, developing new post-processing methods and protocols for AM technology is also a crucial link for bridging the upstream and downstream chains of the entire AM industry.

This Special Issue aims to provide a forum for the researchers and practitioners from academia and industries to publish the experimental and theoretical results on post-processing for additive manufacturing and to contribute to quality improvement and rapid application of additively manufactured parts.

In this Special Issue, original research articles and reviews are welcome. Research areas may include, but are not limited to, the following:

  • New equipment/device and processes for improving surface quality;
  • Coatings on additively manufactured parts for wear resistance, corrosion resistance and other functionalities;
  • Heat treatment;
  • Polishing: physical-field-assisted polishing, mechanical/chemical/electrochemical hybrid processes, etc.;
  • Precision and ultra-precision machining;
  • Hybrid manufacturing: combination of additive and subtractive manufacturing;
  • Materials and interfacial characterization of additively manufactured multi-materials;
  • Functional surface and structure through additive manufacturing and post-processing;
  • Coatings and surface modification through additive manufacturing and post-processing;
  • Health, safety and sustainability issues in post-processing for additive manufacturing.

We look forward to receiving your contributions.

Dr. Yuchao Bai
Dr. Hao Wang
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. Coatings is an international peer-reviewed open access monthly 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 2600 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
  • post-processing
  • surface modification
  • interface property
  • material characterization
  • hybrid manufacturing
  • multi-material
  • dimension accuracy
  • machining

Published Papers (7 papers)

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Research

20 pages, 21260 KiB  
Article
Graded Minimal Surface Structures with High Specific Strength for Broadband Sound Absorption Produced by Laser Powder Bed Fusion
by Mingkang Zhang, Chang Liu, Mingjian Deng, Yuhao Li, Jinwei Li and Di Wang
Coatings 2023, 13(11), 1950; https://doi.org/10.3390/coatings13111950 - 15 Nov 2023
Cited by 1 | Viewed by 941
Abstract
In this research, a design method for triply periodic minimal surface (TPMS) structures with a high specific strength for broadband sound absorption is proposed. The graded TPMS structures are controlled by linear, quadratic, and sine functions. Homogeneous TPMSs and graded TPMSs were manufactured [...] Read more.
In this research, a design method for triply periodic minimal surface (TPMS) structures with a high specific strength for broadband sound absorption is proposed. The graded TPMS structures are controlled by linear, quadratic, and sine functions. Homogeneous TPMSs and graded TPMSs were manufactured by laser powder bed fusion (LPBF) with AlSi7Mg powder, and acoustic impedance tube, compression, and digital image correlation (DIC) tests were applied to obtain the sound absorption and compression properties. The sound absorption coefficient of a homogeneous gyroid increases as the height and offset thickness of the surface increase, and it increases as element size decreases. The sound absorption peak shifts to low frequencies as the height of the structure increases. The average sound absorption coefficient at 1/3 octave from 500 to 6300 Hz of the graded TPMS with a porosity from 60.51 to 77.59% (surface of incident sound wave to rigid backing) is superior to that of the graded TPMS with a porosity from 77.59 to 60.51%, but the latter has a broadband sound absorption coefficient. The compression and DIC results of graded TPMS also show excellent mechanical properties and energy absorption characteristics. Full article
(This article belongs to the Special Issue Recent Development in Post-processing for Additive Manufacturing)
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16 pages, 18714 KiB  
Article
Effect of Y2O3 Content on Microstructure and Corrosion Properties of Laser Cladding Ni-Based/WC Composite Coated on 316L Substrate
by Feilong Liang, Kaiyue Li, Wenqing Shi and Zhikai Zhu
Coatings 2023, 13(9), 1532; https://doi.org/10.3390/coatings13091532 - 01 Sep 2023
Cited by 1 | Viewed by 1020
Abstract
To improve the corrosion resistance of 316L substrate and lengthen its useful life in marine environments, Ni-based/WC/Y2O3 cladding layers with different Y2O3 contents were fabricated on 316L stainless steel using laser cladding technology. The influence of Y [...] Read more.
To improve the corrosion resistance of 316L substrate and lengthen its useful life in marine environments, Ni-based/WC/Y2O3 cladding layers with different Y2O3 contents were fabricated on 316L stainless steel using laser cladding technology. The influence of Y2O3 additives on the microstructure and properties of the cladding coatings was investigated by using scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, a microhardness tester, an electrochemical workstation and a tribometer. Results show that the metallurgical bonding is well formed between the coating and the 316L substrate. The coating consisted primarily of γ-Ni phase and carbides. Adding an appropriate amount of Y2O3 can effectively refine the microstructure and inhibit the precipitation of the carbide hard phase; in addition, the added rare earth element can promote the solid-solution-strengthening effect of the cladding coatings, thus improving the microhardness and wear resistance of the cladding coatings and their electrochemical corrosion property in 3.5 wt% NaCl solution. The hardness of the Ni-based/WC coatings was substantially higher than that of the substrate, and it was greatest at a Y2O3 content of 1%. The corrosion and wear resistance of Y2O3-modified Ni-based/WC composite coatings are significantly better than those of the composite coating without Y2O3. Full article
(This article belongs to the Special Issue Recent Development in Post-processing for Additive Manufacturing)
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15 pages, 17249 KiB  
Article
Effects of Y2O3 Content on Wear Resistance and Corrosion Resistance of 316L/TiC Coating Fabricated by Laser Cladding
by Donghe Jia, Wenqing Shi, Hao Zhang, Teng Wu, Yalong Diao, Kaiyue Li and Chao Lu
Coatings 2023, 13(8), 1348; https://doi.org/10.3390/coatings13081348 - 31 Jul 2023
Cited by 4 | Viewed by 1000
Abstract
Laser cladding technology is a surface modification technology emerging in recent years, and it is widely used in the marine engineering field. Since the structural steels used in marine engineering are mostly carbon steels, their wear resistance and corrosion resistance are poor. In [...] Read more.
Laser cladding technology is a surface modification technology emerging in recent years, and it is widely used in the marine engineering field. Since the structural steels used in marine engineering are mostly carbon steels, their wear resistance and corrosion resistance are poor. In this paper, 316 L stainless steel/TiC composite coatings with different Y2O3 addition amounts were fabricated on Q355B steel surface using the laser cladding technology, and the phase composition, microstructure, microhardness, wear resistance, and corrosion resistance of the coatings were investigated with an X-ray diffractometer (XRD), a scanning electron microscope (SEM), a digital microhardness tester, a friction and wear tester, and an electrochemical workstation. When Y2O3 is added, the crystals in the bottom part of the coating are basically broken and the organisation becomes more dense. When the Y2O3 addition amount is 2%, the hardness is highest, the frictional coefficient curve of the coating exhibits a stable descending trend, and the coating mass loss is the lowest. When Y2O3 is added at 1%, the dynamic potential polarisation curve shows high corrosion potential and low corrosion current density and exhibited the best performance in EIS. The added Y2O3 evidently improves the wear resistance and corrosion resistance of 316 L stainless steel/TiC composite coatings, and this provides a new possibility that a composite coating modified with rare earth oxide is used for repair of marine engineering structures. Full article
(This article belongs to the Special Issue Recent Development in Post-processing for Additive Manufacturing)
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13 pages, 3916 KiB  
Article
Effect of W Content on Microstructure and Properties of Laser Cladding CoCrFeNi HEA Coating
by Fangyan Luo, Tuchuan Yang, Yang Zhao, Zhengye Xiong and Jiang Huang
Coatings 2023, 13(8), 1301; https://doi.org/10.3390/coatings13081301 - 25 Jul 2023
Cited by 1 | Viewed by 834
Abstract
The 316L SS surfaces were prepared with CoCrFeNi HEA/W-composite coatings using the laser cladding technique with various mass fractions of W. The mass fractions of W were 10, 20, 30, and 40%. The microstructure of the HEA/W-composite coatings was investigated using a variety [...] Read more.
The 316L SS surfaces were prepared with CoCrFeNi HEA/W-composite coatings using the laser cladding technique with various mass fractions of W. The mass fractions of W were 10, 20, 30, and 40%. The microstructure of the HEA/W-composite coatings was investigated using a variety of characterization methods. According to the results, the samples were in the BBC phase. In the SEM images, a solid–liquid bonding layer was observed, which indicates the samples had good metallurgical bonding. The W particles prevented the orderly growth of the HEA grains, and a significant refinement of the grains around the W particles occurred. The lattice constants measured by XRD mapping indicate that adding W particles to CoCrFeNi HEA leads to lattice distortion. The hardness of the HEA/W coatings was substantially higher than the substrate and the pure CoCrFeNi coating by hardness measurements and was greatest at a W content of 40%. The hardness of the HEA/W coatings was significantly increased compared to the substrate and the pure CoCrFeNi coating by hardness measurements and was greatest at a W content of 40%. The HEA/W coating was tested for electrochemical corrosion, and a 10% mass fraction of W achieved the highest level of corrosion resistance. Full article
(This article belongs to the Special Issue Recent Development in Post-processing for Additive Manufacturing)
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18 pages, 18092 KiB  
Article
Study on the Anisotropy of Triply Periodic Minimal Surface Porous Structures
by Mingkang Zhang, Jinwei Li, Chang Liu, Mingjian Deng, Xing Liao and Di Wang
Coatings 2023, 13(7), 1206; https://doi.org/10.3390/coatings13071206 - 05 Jul 2023
Cited by 1 | Viewed by 1123
Abstract
Because their topological structures have certain crystallographic symmetry, there is anisotropy in triply periodic minimal surface (TPMS) porous structures. Anisotropy can affect the mechanical properties of porous structures; thus, it is necessary to research the anisotropy of TPMS structures. In this study, based [...] Read more.
Because their topological structures have certain crystallographic symmetry, there is anisotropy in triply periodic minimal surface (TPMS) porous structures. Anisotropy can affect the mechanical properties of porous structures; thus, it is necessary to research the anisotropy of TPMS structures. In this study, based on quaternionic three-dimensional rotation, TPMS structures were rotated around three crystal directions: [100], [110], and [111]. The mechanical anisotropy behaviors of TPMS porous structures, including gyroid, diamond, primitive, and I-graph-wrapped package (IWP) graph surfaces, were studied through finite element analysis (FEA). The FEA results show that the anisotropy of the IWP structure with rotation in the [110] direction was the most significant, and its relative elastic modulus increased by 275.33% when the IWP was rotated 60° in the [110] direction. These results indicate that the uniaxial compression performance of TPMS structures can be significantly improved by using structural anisotropy. However, it should be noted that due to this significant anisotropy, the performance of such structures will significantly decrease in specific directions. For example, after the primitive structure was rotated 60° in the [111] and [110] directions, its relative elastic modulus decreased by 72.66% and 77.6%, respectively. Therefore, it was necessary to reasonably consider the bearing capacity in fragile directions under complex working conditions. Based on the anisotropy of TPMS, gradient TPMS structures with three rotation angles were designed and manufactured using selective laser melting technology. The compressive results show that multi-peaks appeared in the primitive structure with gradient rotation in the [111] direction from 0° to 40°, and step-by-step behaviors were observed in the IWP structure with gradient rotation in the [110] direction from 0° to 60°. This result shows that the yielding platform can be enhanced using gradient rotation designation based on the anisotropy of TPMS porous structures. Full article
(This article belongs to the Special Issue Recent Development in Post-processing for Additive Manufacturing)
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10 pages, 3622 KiB  
Article
Design and Development of 3D-Printed Personalized Femoral Prosthesis Technologies
by Guoqing Zhang, Junxin Li, Huimin Zeng, Wan Li, Qiang Wang and Aibing Huang
Coatings 2023, 13(6), 1044; https://doi.org/10.3390/coatings13061044 - 05 Jun 2023
Cited by 1 | Viewed by 1224
Abstract
The femur supports the entire body weight, and any damage or necrosis to this bone can significantly impair normal walking. Therefore, repairing the femur is essential to restoring its function. However, due to variations in human bone structure, standardized prostheses often deliver poor [...] Read more.
The femur supports the entire body weight, and any damage or necrosis to this bone can significantly impair normal walking. Therefore, repairing the femur is essential to restoring its function. However, due to variations in human bone structure, standardized prostheses often deliver poor repair outcomes. We used the medical three-dimensional (3D) auxiliary software Mimics to design personalized femoral prostheses to address this issue. The femoral prosthesis filler was porous, and all aspects of the prosthesis were thoroughly studied and analyzed before direct molding using 3D printing technology. The personalized femoral prosthesis filler and bone plate designed using 3D printing technology have positive effects, and the matching between the femoral prosthesis, bone plate, and filler is satisfactory. The pore structure of the 3D-printed femoral prosthesis filler and the bone plate is clear and of high quality, which shortens the research and development cycle and reduces costs, providing a foundation for the direct application of 3D-printed personalized prostheses. Full article
(This article belongs to the Special Issue Recent Development in Post-processing for Additive Manufacturing)
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12 pages, 2873 KiB  
Article
Influence of Al Addition on the Microstructure and Wear Behavior of Laser Cladding FeCoCrNiAlx High-Entropy Alloy Coatings
by Yang Liu, Zhixiang Xu, Gaojie Xu and Hongyong Chen
Coatings 2023, 13(2), 426; https://doi.org/10.3390/coatings13020426 - 13 Feb 2023
Cited by 3 | Viewed by 1226
Abstract
In order to improve the wear properties of FeCoCrNi high entropy alloy (HEA), laser cladding was applied to fabricate FeCoCrNiAlx HEA coatings with different Al additions. The Al-modified coatings exhibited excellent metallurgical bonding interfaces with the substrates. The microstructure of FeCoCrNiAl0.5 [...] Read more.
In order to improve the wear properties of FeCoCrNi high entropy alloy (HEA), laser cladding was applied to fabricate FeCoCrNiAlx HEA coatings with different Al additions. The Al-modified coatings exhibited excellent metallurgical bonding interfaces with the substrates. The microstructure of FeCoCrNiAl0.5 coating was the same as of the FeCoCrNi coating: face-centered cubic (FCC). However, the microstructure of FeCoCrNiAl was different: body-centered cubic (BCC) with more Al atoms distributed inside the grains. As the Al content in the coating was increased, the hardness increased as well from 202 to 546 HV0.2, while CoF and wear rate decreased from 0.62 to 0.1 and from 8.55 × 10−7 to 8.24 × 10−9 mm3/(Nm), respectively. The wear mechanisms changed from the mixture of abrasive, adhesive, and oxidative wear patterns to the mixture of abrasive and oxidative patterns. Such a change indicates that the Al addition indeed improved the wear resistance of FeCoCrNiAlx HEA coatings. Our results expand knowledge on HEA coating applications as wear-resistant materials in various applied industrial fields. Full article
(This article belongs to the Special Issue Recent Development in Post-processing for Additive Manufacturing)
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