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Metal additive manufacturing has significantly evolved since the 1990s, achieving a market valuation of USD 6.36 billion in 2022, with an anticipated compound annual growth rate of 24.2% from 2023 to 2030. While powder-bed-based methods like powder bed fusion and binder jetting dominate the market due to their high accuracy and resolution, they face challenges such as lengthy build times, excessive costs, and safety concerns. Non-powder-bed-based techniques, including direct energy deposition, material extrusion, and sheet lamination, offer advantages such as larger build sizes and lower energy consumption but also encounter issues like residual stress and poor surface finish. The existing reviews of non-powder-bed-based metal additive manufacturing are restricted to one technical branch or one specific material. This survey investigates and analyzes each non-powder-bed-based technique in terms of its manufacturing method, materials, product quality, and summary for easy understanding and comparison. Innovative designs and research status are included.
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A Review on Progress, Challenges, and Prospects of Material Jetting of Copper and Tungsten
Copper (Cu) and tungsten (W) possess exceptional electrical and thermal conductivity properties, making them suitable candidates for applications such as interconnects and thermal conductivity enhancements. Solution-based additive manufacturing (SBAM) offers unique advantages, including patterning capabilities, cost-effectiveness, and scalability among the various methods for manufacturing Cu and W-based films and structures. In particular, SBAM material jetting techniques, such as inkjet printing (IJP), direct ink writing (DIW), and aerosol jet printing (AJP), present a promising approach for design freedom, low material wastes, and versatility as either stand-alone printers or integrated with powder bed-based metal additive manufacturing (MAM). Thus, this review summarizes recent advancements in solution-processed Cu and W, focusing on IJP, DIW, and AJP techniques. The discussion encompasses general aspects, current status, challenges, and recent research highlights. Furthermore, this paper addresses integrating material jetting techniques with powder bed-based MAM to fabricate functional alloys and multi-material structures. Finally, the factors influencing large-scale fabrication and potential prospects in this area are explored.
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- Award ID(s):
- 1941262
- PAR ID:
- 10573008
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Nanomaterials
- Volume:
- 13
- Issue:
- 16
- ISSN:
- 2079-4991
- Page Range / eLocation ID:
- 2303
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Binder jetting is an additive manufacturing process utilizing a liquid-based binding agent to selectively join the material in a powder bed. It is capable of manufacturing complex-shaped parts from a variety of materials including metals, ceramics, and polymers. This paper provides a comprehensive review on currently available reports on metal binder jetting from both academia and industry. Critical factors and their effects in metal binder jetting are reviewed and divided into two categories, namely material-related factors and process-related parameters. The reported data on density, dimensional and geometric accuracy, and mechanical properties achieved by metal binder jetting are summarized. With parameter optimization and a suitable sintering process, ten materials have been proven to achieve a relative density of higher than 90%. Indepth discussion is provided regarding densification as a function of various attributes of powder packing, printing, and post-processing. A few grades of stainless steel obtained equivalent or superior mechanical properties compared to cold working. Although binder jetting has gained its popularity in the past several years, it has not been sufficiently studied compared with other metal additive manufacturing (AM) processes such as powder bed fusion and directed energy deposition. Some aspects that need further research include the understanding of powder spreading process, binder-powder interaction, and part shrinkage.more » « less
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Additive manufacturing (AM) as a disruptive technique has offered great potential to design and fabricate many metallic components for aerospace, medical, nuclear, and energy applications where parts have complex geometry. However, a limited number of materials suitable for the AM process is one of the shortcomings of this technique, in particular laser AM of copper (Cu) is challenging due to its high thermal conductivity and optical reflectivity, which requires higher heat input to melt powders. Fabrication of composites using AM is also very challenging and not easily achievable using the current powder bed technologies. Here, the feasibility to fabricate pure copper and copper-carbon nanotube (Cu-CNT) composites was investigated using laser powder bed fusion additive manufacturing (LPBF-AM), and 10 × 10 × 10 mm3 cubes of Cu and Cu-CNTs were made by applying a Design of Experiment (DoE) varying three parameters: laser power, laser speed, and hatch spacing at three levels. For both Cu and Cu-CNT samples, relative density above 90% and 80% were achieved, respectively. Density measurement was carried out three times for each sample, and the error was found to be less than 0.1%. Roughness measurement was performed on a 5 mm length of the sample to obtain statistically significant results. As-built Cu showed average surface roughness (Ra) below 20 µm; however, the surface of AM Cu-CNT samples showed roughness values as large as 1 mm. Due to its porous structure, the as-built Cu showed thermal conductivity of ~108 W/m·K and electrical conductivity of ~20% IACS (International Annealed Copper Standard) at room temperature, ~70% and ~80% lower than those of conventionally fabricated bulk Cu. Thermal conductivity and electrical conductivity were ~85 W/m·K and ~10% IACS for as-built Cu-CNT composites at room temperature. As-built Cu-CNTs showed higher thermal conductivity as compared to as-built Cu at a temperature range from 373 K to 873 K. Because of their large surface area, light weight, and large energy absorbing behavior, porous Cu and Cu-CNT materials can be used in electrodes, catalysts and their carriers, capacitors, heat exchangers, and heat and impact absorption.more » « less
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Binder jetting additive manufacturing (AM) is an innovative form of 3D printing that generates complex and advanced structures of various materials by jetting binder drops onto a powder bed. The drops on the bed cure the powder to form structures in a quick and efficient manner. However, the method suffers several flaws including manufacturing inconsistencies and coarse resolution of structures. These flaws may be explained by complex interactions between the binder drop and the powder during the printing process. Therefore, a better understanding of these interactions will be instrumental in the development of binder jetting for fabricating multipurpose, higher quality functional structures. In this study, these complex interactions are analyzed during the impact and subsequent processes. The impact dynamics of binder drops on a powder surface were examined by using a custom impingement rig under various test conditions (i.e., different impact velocities and binder viscosities). A high-speed imaging system was used to capture the transient details of the drop-powder interactions. This study concludes that an increase in drop impact velocity results in a greater range of particle ejection. A lower drop viscosity results in a higher dry spread of particles while a higher drop viscosity results in a greater number of binder-encapsulated particles. Across all cases, binder drops absorb particle granules at a rate inverse to their viscosity.more » « less
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Binder jetting (BJ) is an additive manufacturing process that uses a powder feedstock in a layer wise process to print parts by selectively depositing a liquid binder into the powder bed using inkjet technology. This study presents findings from high-speed synchrotron imaging of binder droplet-interaction during the BJ printing process. A custom laboratory-scale BJ test platform was used for testing which enabled control of relevant process parameters including powder material, print geometry, spacing between droplets, powder bed density, and powder moisture content. Powder ejection was observed above the powder bed surface and powder relocation due to droplet impact was observed below the powder bed surface. Powder relocation was observed to be sensitive to powder material, powder bed density, powder bed moisture, droplet spacing, and print geometry. Increasing powder bed density was found to increase particle ejection velocity but reduce the total number of particles ejected. Process parameters that increase binder / moisture content in the powder bed were found to reduce powder ejection. The number of ejected powder particles was reduced for lower droplet spacings. Both powder ejection and powder relocation below the powder bed were reduced by treating the surface of the powder bed with a water/triethylene glycol (TEG) mixture before printing. Results from this study help to build understanding of the physical mechanisms in the BJ printing process that may contribute to formation of defects observed in final parts.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3390/nano13162303
