Inspired by natural porous architectures, numerous attempts have been made to generate porous structures. Owing to the smooth surfaces, highly interconnected porous architectures, and mathematical controllable geometry features, triply periodic minimal surface (TPMS) is emerging as an outstanding solution to constructing porous structures in recent years. However, many advantages of TPMS are not fully utilized in current research. Critical problems of the process from design, manufacturing to applications need further systematic and integrated discussions. In this work, a comprehensive overview of TPMS porous structures is provided. In order to generate the digital models of TPMS, the geometry design algorithms and performance control strategies are introduced according to diverse requirements. Based on that, precise additive manufacturing methods are summarized for fabricating physical TPMS products. Furthermore, actual multidisciplinary applications are presented to clarify the advantages and further potential of TPMS porous structures. Eventually, the existing problems and further research outlooks are discussed.
ISSN: 2631-7990
The International Journal of Extreme Manufacturing is a multidisciplinary journal uniquely covering the areas related to extreme manufacturing. The journal is devoted to publishing original articles and reviews of the highest quality and impact in the areas related to extreme manufacturing, ranging from fundamentals to process, measurement, and systems, as well as materials, structures, and devices with extreme functionalities.
Open all abstracts, in this tab
Jiawei Feng et al 2022 Int. J. Extrem. Manuf. 4 022001
Huiyuan Wang et al 2024 Int. J. Extrem. Manuf. 6 045004
3D printing techniques offer an effective method in fabricating complex radially multi-material structures. However, it is challenging for complex and delicate radially multi-material model geometries without supporting structures, such as tissue vessels and tubular graft, among others. In this work, we tackle these challenges by developing a polar digital light processing technique which uses a rod as the printing platform. The 3D model fabrication is accomplished through line projection. The rotation and translation of the rod are synchronized to project and illuminate the photosensitive material volume. By controlling the distance between the rod and the printing window, we achieved the printing of tubular structures with a minimum wall thickness as thin as 50 micrometers. By controlling the width of fine slits at the printing window, we achieved the printing of structures with a minimum feature size of 10 micrometers. Our process accomplished the fabrication of thin-walled tubular graft structure with a thickness of only 100 micrometers and lengths of several centimeters within a timeframe of just 100 s. Additionally, it enables the printing of axial multi-material structures, thereby achieving adjustable mechanical strength. This method is conducive to rapid customization of tubular grafts and the manufacturing of tubular components in fields such as dentistry, aerospace, and more.
Highlights
Polar-coordinate-based line projection enables rapid printing of tubular structures with higher precision and compressive strength.
Using a cylindrical auxiliary axis allows for the manufacture of radial multi-material structures and facilitates printing of coaxial structures.
It is beneficial for the rapid customization of tubular implants and for manufacturing tubular components in dentistry, aerospace, and other fields.
Wanwan Fan et al 2024 Int. J. Extrem. Manuf. 6 045101
Innovative pulsed current-assisted multi-pass rolling tests were conducted on a 12-roll mill during the rolling deformation processing of SUS304 ultra-thin strips. The results show that in the first rolling pass, the rolling reduction rate of a conventionally rolled sample (at room temperature) is 33.8%, which can be increased to 41.5% by pulsed current-assisted rolling, enabling the formation of an ultra-thin strip with a size of 67.3 μm in only one rolling pass. After three passes of pulsed current-assisted rolling, the thickness of the ultra-thin strip can be further reduced to 51.7 μm. To clearly compare the effects of a pulsed current on the microstructure and mechanical response of the ultra-thin strip, ultra-thin strips with nearly the same thickness reduction were analyzed. It was found that pulsed current can reduce the degree of work-hardening of the rolled samples by promoting dislocation detachment, reducing the density of stacking faults, inhibiting martensitic phase transformation, and shortening the total length of grain boundaries. As a result, the ductility of ultra-thin strips can be effectively restored to approximately 16.3% while maintaining a high tensile strength of 1118 MPa.Therefore, pulsed current-assisted rolling deformation shows great potential for the formation of ultra-thin strips with a combination of high strength and ductility.
Highlights
Pulsed current-assisted SUS304 ultra-thin strips rolling tests were conducted using a 12-roll precision cold mill.
The reduction rate increases from 33.8% to 41.5% by pulsed current-assisted rolling under the same roll gap setting.
The ductility of electrically rolled sample can be restored to 16.3% while maintaining a high tensile strength of 1118 MPa.
Pulsed current decreases the degree of work-hardening of the rolled samples by reducing dislocation densities, weakening texture intensities, and inhibiting martensitic transformation.
Jinlong Zhu et al 2022 Int. J. Extrem. Manuf. 4 032001
The growing demand for electronic devices, smart devices, and the Internet of Things constitutes the primary driving force for marching down the path of decreased critical dimension and increased circuit intricacy of integrated circuits. However, as sub-10 nm high-volume manufacturing is becoming the mainstream, there is greater awareness that defects introduced by original equipment manufacturer components impact yield and manufacturing costs. The identification, positioning, and classification of these defects, including random particles and systematic defects, are becoming more and more challenging at the 10 nm node and beyond. Very recently, the combination of conventional optical defect inspection with emerging techniques such as nanophotonics, optical vortices, computational imaging, quantitative phase imaging, and deep learning is giving the field a new possibility. Hence, it is extremely necessary to make a thorough review for disclosing new perspectives and exciting trends, on the foundation of former great reviews in the field of defect inspection methods. In this article, we give a comprehensive review of the emerging topics in the past decade with a focus on three specific areas: (a) the defect detectability evaluation, (b) the diverse optical inspection systems, and (c) the post-processing algorithms. We hope, this work can be of importance to both new entrants in the field and people who are seeking to use it in interdisciplinary work.
Hao Wang et al 2024 Int. J. Extrem. Manuf. 6 042002
Optical imaging systems have greatly extended human visual capabilities, enabling the observation and understanding of diverse phenomena. Imaging technologies span a broad spectrum of wavelengths from x-ray to radio frequencies and impact research activities and our daily lives. Traditional glass lenses are fabricated through a series of complex processes, while polymers offer versatility and ease of production. However, modern applications often require complex lens assemblies, driving the need for miniaturization and advanced designs with micro- and nanoscale features to surpass the capabilities of traditional fabrication methods. Three-dimensional (3D) printing, or additive manufacturing, presents a solution to these challenges with benefits of rapid prototyping, customized geometries, and efficient production, particularly suited for miniaturized optical imaging devices. Various 3D printing methods have demonstrated advantages over traditional counterparts, yet challenges remain in achieving nanoscale resolutions. Two-photon polymerization lithography (TPL), a nanoscale 3D printing technique, enables the fabrication of intricate structures beyond the optical diffraction limit via the nonlinear process of two-photon absorption within liquid resin. It offers unprecedented abilities, e.g. alignment-free fabrication, micro- and nanoscale capabilities, and rapid prototyping of almost arbitrary complex 3D nanostructures. In this review, we emphasize the importance of the criteria for optical performance evaluation of imaging devices, discuss material properties relevant to TPL, fabrication techniques, and highlight the application of TPL in optical imaging. As the first panoramic review on this topic, it will equip researchers with foundational knowledge and recent advancements of TPL for imaging optics, promoting a deeper understanding of the field. By leveraging on its high-resolution capability, extensive material range, and true 3D processing, alongside advances in materials, fabrication, and design, we envisage disruptive solutions to current challenges and a promising incorporation of TPL in future optical imaging applications.
Highlights
Provide a comprehensive overview of two-photon polymerization lithography (TPL)-based imaging applications.
Introduce the fundamental imaging theories, key materials properties, and fabrication technologies.
Classify and summarize the various imaging applications of TPL.
Envisage the future trends of TPL for imaging optics and offer insights on the potential solutions to current challenges.
Aditya Chivate and Chi Zhou 2024 Int. J. Extrem. Manuf. 6 042004
Over the course of millions of years, nature has evolved to ensure survival and presents us with a myriad of functional surfaces and structures that can boast high efficiency, multifunctionality, and sustainability. What makes these surfaces particularly practical and effective is the intricate micropatterning that enables selective interactions with microstructures. Most of these structures have been realized in the laboratory environment using numerous fabrication techniques by tailoring specific surface properties. Of the available manufacturing methods, additive manufacturing (AM) has created opportunities for fabricating these structures as the complex architectures of the naturally occurring microstructures far exceed the traditional ways. This paper presents a concise overview of the fundamentals of such patterned microstructured surfaces, their fabrication techniques, and diverse applications. A comprehensive evaluation of micro fabrication methods is conducted, delving into their respective strengths and limitations. Greater emphasis is placed on AM processes like inkjet printing and micro digital light projection printing due to the intrinsic advantages of these processes to additively fabricate high resolution structures with high fidelity and precision. The paper explores the various advancements in these processes in relation to their use in microfabrication and also presents the recent trends in applications like the fabrication of microlens arrays, microneedles, and tissue scaffolds.
Highlights
Provide a comprehensive overview of the different micromanufacturing techniques with a detailed focus on drop-on-demand (DOD) inkjet printing and DLP based printing.
Introduce the working principles of DOD inkjet printing and DLP printing and discuss the current status pertaining to micro fabrication.
Summarize notable applications of DOD and DLP based printing technology at micro scales.
Discuss the following challenges, limitations and offer valuable insights and prospects into the current state of DLP based and DOD inkjet printing technology.
Mingzhu Xie et al 2024 Int. J. Extrem. Manuf. 6 032005
Microfluidic devices are composed of microchannels with a diameter ranging from ten to a few hundred micrometers. Thus, quite a small (10−9–10−18 l) amount of liquid can be manipulated by such a precise system. In the past three decades, significant progress in materials science, microfabrication, and various applications has boosted the development of promising functional microfluidic devices. In this review, the recent progress on novel microfluidic devices with various functions and applications is presented. First, the theory and numerical methods for studying the performance of microfluidic devices are briefly introduced. Then, materials and fabrication methods of functional microfluidic devices are summarized. Next, the recent significant advances in applications of microfluidic devices are highlighted, including heat sinks, clean water production, chemical reactions, sensors, biomedicine, capillaric circuits, wearable electronic devices, and microrobotics. Finally, perspectives on the challenges and future developments of functional microfluidic devices are presented. This review aims to inspire researchers from various fields—engineering, materials, chemistry, mathematics, physics, and more—to collaborate and drive forward the development and applications of functional microfluidic devices, specifically for achieving carbon neutrality.
Highlights:
The theory and numerical methods for microfluidic devices are briefly introduced.
The materials and recent advanced microfabrication methods for functional microfluidic devices are summarized.
Recent novel microfluidic devices with various promising functions and applications are presented.
The challenges and future developments of functional microfluidics for the specific purpose of carbon neutrality are predicted.
Amit Bandyopadhyay et al 2023 Int. J. Extrem. Manuf. 5 032014
Porous metals are extensively used in load-bearing implants to improve osseointegration.
Different processing approaches for porous metals are discussed here.
Static and dynamic mechanical properties are critically reviewed for porous metal implants.
In vitro and in vivo biological properties of porous metal implants are critically reviewed.
Current challenges and future directions for porous metal implants are discussed.
Abstract
Porous and functionally graded materials have seen extensive applications in modern biomedical devices—allowing for improved site-specific performance; their appreciable mechanical, corrosive, and biocompatible properties are highly sought after for lightweight and high-strength load-bearing orthopedic and dental implants. Examples of such porous materials are metals, ceramics, and polymers. Although, easy to manufacture and lightweight, porous polymers do not inherently exhibit the required mechanical strength for hard tissue repair or replacement. Alternatively, porous ceramics are brittle and do not possess the required fatigue resistance. On the other hand, porous biocompatible metals have shown tailorable strength, fatigue resistance, and toughness. Thereby, a significant interest in investigating the manufacturing challenges of porous metals has taken place in recent years. Past research has shown that once the advantages of porous metallic structures in the orthopedic implant industry have been realized, their biological and biomechanical compatibility—with the host bone—has been followed up with extensive methodical research. Various manufacturing methods for porous or functionally graded metals are discussed and compared in this review, specifically, how the manufacturing process influences microstructure, graded composition, porosity, biocompatibility, and mechanical properties. Most of the studies discussed in this review are related to porous structures for bone implant applications; however, the understanding of these investigations may also be extended to other devices beyond the biomedical field.
Xingran Li et al 2024 Int. J. Extrem. Manuf. 6 042003
Over millions of years of natural evolution, organisms have developed nearly perfect structures and functions. The self-fabrication of organisms serves as a valuable source of inspiration for designing the next-generation of structural materials, and is driving the future paradigm shift of modern materials science and engineering. However, the complex structures and multifunctional integrated optimization of organisms far exceed the capability of artificial design and fabrication technology, and new manufacturing methods are urgently needed to achieve efficient reproduction of biological functions. As one of the most valuable advanced manufacturing technologies of the 21st century, laser processing technology provides an efficient solution to the critical challenges of bionic manufacturing. This review outlines the processing principles, manufacturing strategies, potential applications, challenges, and future development outlook of laser processing in bionic manufacturing domains. Three primary manufacturing strategies for laser-based bionic manufacturing are elucidated: subtractive manufacturing, equivalent manufacturing, and additive manufacturing. The progress and trends in bionic subtractive manufacturing applied to micro/nano structural surfaces, bionic equivalent manufacturing for surface strengthening, and bionic additive manufacturing aiming to achieve bionic spatial structures, are reported. Finally, the key problems faced by laser-based bionic manufacturing, its limitations, and the development trends of its existing technologies are discussed.
Highlights
Provide a comprehensive overview of laser-based bionic manufacturing technology and its applications.
Present remarkable progress in bionic manufacturing through laser subtractive manufacturing, laser equivalent manufacturing, and laser additive manufacturing.
Outline research limitations and prospects for the development of laser-based bionic manufacturing.
Hye-Mi Kim et al 2023 Int. J. Extrem. Manuf. 5 012006
Since the first report of amorphous In–Ga–Zn–O based thin film transistors, interest in oxide semiconductors has grown. They offer high mobility, low off-current, low process temperature, and wide flexibility for compositions and processes. Unfortunately, depositing oxide semiconductors using conventional processes like physical vapor deposition leads to problematic issues, especially for high-resolution displays and highly integrated memory devices. Conventional approaches have limited process flexibility and poor conformality on structured surfaces. Atomic layer deposition (ALD) is an advanced technique which can provide conformal, thickness-controlled, and high-quality thin film deposition. Accordingly, studies on ALD based oxide semiconductors have dramatically increased recently. Even so, the relationships between the film properties of ALD-oxide semiconductors and the main variables associated with deposition are still poorly understood, as are many issues related to applications. In this review, to introduce ALD-oxide semiconductors, we provide: (a) a brief summary of the history and importance of ALD-based oxide semiconductors in industry, (b) a discussion of the benefits of ALD for oxide semiconductor deposition (in-situ composition control in vertical distribution/vertical structure engineering/chemical reaction and film properties/insulator and interface engineering), and (c) an explanation of the challenging issues of scaling oxide semiconductors and ALD for industrial applications. This review provides valuable perspectives for researchers who have interest in semiconductor materials and electronic device applications, and the reasons ALD is important to applications of oxide semiconductors.
Highlights
The history of oxide semiconductors and topics related to ALD-oxide semiconductors are reviewed.
The benefits of ALD-oxide semiconductors for electronic devices applications are discussed.
Challenging issues and the outlook for future development and scalability in industry are reviewed.
Open all abstracts, in this tab
Jianxiang Cheng et al 2024 Int. J. Extrem. Manuf. 6 042006
Multimaterial (MM) 3D printing shows great potential for application in metamaterials, flexible electronics, biomedical devices and robots, since it can seamlessly integrate distinctive materials into one printed structure. Among numerous MM 3D printing technologies, digital light processing (DLP) MM 3D printing is compatible with a wide range of materials from hydrogels to ceramics, and can print MM 3D structures with high resolution, high complexity and fast speed. This paper introduces the fundamental mechanisms of DLP 3D printing, and reviews the recent advances of DLP MM 3D printing technologies with emphasis on material switching methods and material contamination issues. It also summarizes a number of typical examples of DLP MM 3D printing systems developed in the past decade, and introduces their system structures, working principles, material switching methods, residual resin removal methods, printing steps, as well as the representative structures and applications. Finally, we provide perspectives on the directions of the further development of DLP MM 3D printing technology.
Highlights
Review the recent advances of digital light processing multimaterial 3D printing.
Summarize critical challenges in digital light processing multimaterial 3D printing.
Provide perspectives on directions of further development of multimaterial 3D printing.
Yongxiang Hu et al 2024 Int. J. Extrem. Manuf. 6 045005
Surface-enhanced Raman spectroscopy (SERS) microfluidic system, which enables rapid detection of chemical and biological analytes, offers an effective platform to monitor various food contaminants and disease diagnoses. The efficacy of SERS microfluidic systems is greatly dependent on the sensitivity and reusability of SERS detection substrates to ensure repeated use for prolonged periods. This study proposed a novel process of femtosecond laser nanoparticle array (NPA) implantation to achieve homogeneous forward transfer of gold NPA on a flexible polymer film and accurately integrated it within microfluidic chips for SERS detection. The implanted Au-NPA strips show a remarkable electromagnetic field enhancement with the factor of 9 × 108 during SERS detection of malachite green (MG) solution, achieving a detection limit lower than 10 ppt, far better than most laser-prepared SERS substrates. Furthermore, Au-NPA strips show excellent reusability after several physical and chemical cleaning, because of the robust embedment of laser-implanted NPA in flexible substrates. To demonstrate the performance of Au-NPA, a SERS microfluidic system is built to monitor the online oxidation reaction between MG/NaClO reactants, which helps infer the reaction path. The proposed method of nanoparticle implantation is more effective than the direct laser structuring technique. It provides better performance for SERS detection, robustness of detection, and substrate flexibility and has a wider range of applications for microfluidic systems without any negative impact.
Highlights
Nanoparticle arrays with high accuracy and uniformity are implanted on flexible substrate.
Prepared substrates achieve a detection limit lower than 10 ppt for SERS detection.
SERS substrates represent excellent reusability and sensitivity in continuous detection.
Nanoparticle arrays are integrated into microfluidic chip to monitor redox reaction.
Ju Young Lee et al 2024 Int. J. Extrem. Manuf. 6 042005
Flexible electronics offer a multitude of advantages, such as flexibility, lightweight property, portability, and high durability. These unique properties allow for seamless applications to curved and soft surfaces, leading to extensive utilization across a wide range of fields in consumer electronics. These applications, for example, span integrated circuits, solar cells, batteries, wearable devices, bio-implants, soft robotics, and biomimetic applications. Recently, flexible electronic devices have been developed using a variety of materials such as organic, carbon-based, and inorganic semiconducting materials. Silicon (Si) owing to its mature fabrication process, excellent electrical, optical, thermal properties, and cost efficiency, remains a compelling material choice for flexible electronics. Consequently, the research on ultra-thin Si in the context of flexible electronics is studied rigorously nowadays. The thinning of Si is crucially important for flexible electronics as it reduces its bending stiffness and the resultant bending strain, thereby enhancing flexibility while preserving its exceptional properties. This review provides a comprehensive overview of the recent efforts in the fabrication techniques for forming ultra-thin Si using top-down and bottom-up approaches and explores their utilization in flexible electronics and their applications.
Highlights
Flexible silicon manufacturing techniques are categorized into two main approaches: top-down and bottom-up depending on the process sequence.
The top-down approach is a method of producing the bulk silicon wafer by scaling down it into nano/micro-sized structures.
The bottom-up approach is a method of creating an intricate structure through precise control of small-scale atoms and molecules.
Flexible silicon maintains the advantages of the bulk silicon such as electrical properties, reliability, and cost-effectiveness.
Wanwan Fan et al 2024 Int. J. Extrem. Manuf. 6 045101
Innovative pulsed current-assisted multi-pass rolling tests were conducted on a 12-roll mill during the rolling deformation processing of SUS304 ultra-thin strips. The results show that in the first rolling pass, the rolling reduction rate of a conventionally rolled sample (at room temperature) is 33.8%, which can be increased to 41.5% by pulsed current-assisted rolling, enabling the formation of an ultra-thin strip with a size of 67.3 μm in only one rolling pass. After three passes of pulsed current-assisted rolling, the thickness of the ultra-thin strip can be further reduced to 51.7 μm. To clearly compare the effects of a pulsed current on the microstructure and mechanical response of the ultra-thin strip, ultra-thin strips with nearly the same thickness reduction were analyzed. It was found that pulsed current can reduce the degree of work-hardening of the rolled samples by promoting dislocation detachment, reducing the density of stacking faults, inhibiting martensitic phase transformation, and shortening the total length of grain boundaries. As a result, the ductility of ultra-thin strips can be effectively restored to approximately 16.3% while maintaining a high tensile strength of 1118 MPa.Therefore, pulsed current-assisted rolling deformation shows great potential for the formation of ultra-thin strips with a combination of high strength and ductility.
Highlights
Pulsed current-assisted SUS304 ultra-thin strips rolling tests were conducted using a 12-roll precision cold mill.
The reduction rate increases from 33.8% to 41.5% by pulsed current-assisted rolling under the same roll gap setting.
The ductility of electrically rolled sample can be restored to 16.3% while maintaining a high tensile strength of 1118 MPa.
Pulsed current decreases the degree of work-hardening of the rolled samples by reducing dislocation densities, weakening texture intensities, and inhibiting martensitic transformation.
Aditya Chivate and Chi Zhou 2024 Int. J. Extrem. Manuf. 6 042004
Over the course of millions of years, nature has evolved to ensure survival and presents us with a myriad of functional surfaces and structures that can boast high efficiency, multifunctionality, and sustainability. What makes these surfaces particularly practical and effective is the intricate micropatterning that enables selective interactions with microstructures. Most of these structures have been realized in the laboratory environment using numerous fabrication techniques by tailoring specific surface properties. Of the available manufacturing methods, additive manufacturing (AM) has created opportunities for fabricating these structures as the complex architectures of the naturally occurring microstructures far exceed the traditional ways. This paper presents a concise overview of the fundamentals of such patterned microstructured surfaces, their fabrication techniques, and diverse applications. A comprehensive evaluation of micro fabrication methods is conducted, delving into their respective strengths and limitations. Greater emphasis is placed on AM processes like inkjet printing and micro digital light projection printing due to the intrinsic advantages of these processes to additively fabricate high resolution structures with high fidelity and precision. The paper explores the various advancements in these processes in relation to their use in microfabrication and also presents the recent trends in applications like the fabrication of microlens arrays, microneedles, and tissue scaffolds.
Highlights
Provide a comprehensive overview of the different micromanufacturing techniques with a detailed focus on drop-on-demand (DOD) inkjet printing and DLP based printing.
Introduce the working principles of DOD inkjet printing and DLP printing and discuss the current status pertaining to micro fabrication.
Summarize notable applications of DOD and DLP based printing technology at micro scales.
Discuss the following challenges, limitations and offer valuable insights and prospects into the current state of DLP based and DOD inkjet printing technology.
Open all abstracts, in this tab
Jianxiang Cheng et al 2024 Int. J. Extrem. Manuf. 6 042006
Multimaterial (MM) 3D printing shows great potential for application in metamaterials, flexible electronics, biomedical devices and robots, since it can seamlessly integrate distinctive materials into one printed structure. Among numerous MM 3D printing technologies, digital light processing (DLP) MM 3D printing is compatible with a wide range of materials from hydrogels to ceramics, and can print MM 3D structures with high resolution, high complexity and fast speed. This paper introduces the fundamental mechanisms of DLP 3D printing, and reviews the recent advances of DLP MM 3D printing technologies with emphasis on material switching methods and material contamination issues. It also summarizes a number of typical examples of DLP MM 3D printing systems developed in the past decade, and introduces their system structures, working principles, material switching methods, residual resin removal methods, printing steps, as well as the representative structures and applications. Finally, we provide perspectives on the directions of the further development of DLP MM 3D printing technology.
Highlights
Review the recent advances of digital light processing multimaterial 3D printing.
Summarize critical challenges in digital light processing multimaterial 3D printing.
Provide perspectives on directions of further development of multimaterial 3D printing.
Ju Young Lee et al 2024 Int. J. Extrem. Manuf. 6 042005
Flexible electronics offer a multitude of advantages, such as flexibility, lightweight property, portability, and high durability. These unique properties allow for seamless applications to curved and soft surfaces, leading to extensive utilization across a wide range of fields in consumer electronics. These applications, for example, span integrated circuits, solar cells, batteries, wearable devices, bio-implants, soft robotics, and biomimetic applications. Recently, flexible electronic devices have been developed using a variety of materials such as organic, carbon-based, and inorganic semiconducting materials. Silicon (Si) owing to its mature fabrication process, excellent electrical, optical, thermal properties, and cost efficiency, remains a compelling material choice for flexible electronics. Consequently, the research on ultra-thin Si in the context of flexible electronics is studied rigorously nowadays. The thinning of Si is crucially important for flexible electronics as it reduces its bending stiffness and the resultant bending strain, thereby enhancing flexibility while preserving its exceptional properties. This review provides a comprehensive overview of the recent efforts in the fabrication techniques for forming ultra-thin Si using top-down and bottom-up approaches and explores their utilization in flexible electronics and their applications.
Highlights
Flexible silicon manufacturing techniques are categorized into two main approaches: top-down and bottom-up depending on the process sequence.
The top-down approach is a method of producing the bulk silicon wafer by scaling down it into nano/micro-sized structures.
The bottom-up approach is a method of creating an intricate structure through precise control of small-scale atoms and molecules.
Flexible silicon maintains the advantages of the bulk silicon such as electrical properties, reliability, and cost-effectiveness.
Aditya Chivate and Chi Zhou 2024 Int. J. Extrem. Manuf. 6 042004
Over the course of millions of years, nature has evolved to ensure survival and presents us with a myriad of functional surfaces and structures that can boast high efficiency, multifunctionality, and sustainability. What makes these surfaces particularly practical and effective is the intricate micropatterning that enables selective interactions with microstructures. Most of these structures have been realized in the laboratory environment using numerous fabrication techniques by tailoring specific surface properties. Of the available manufacturing methods, additive manufacturing (AM) has created opportunities for fabricating these structures as the complex architectures of the naturally occurring microstructures far exceed the traditional ways. This paper presents a concise overview of the fundamentals of such patterned microstructured surfaces, their fabrication techniques, and diverse applications. A comprehensive evaluation of micro fabrication methods is conducted, delving into their respective strengths and limitations. Greater emphasis is placed on AM processes like inkjet printing and micro digital light projection printing due to the intrinsic advantages of these processes to additively fabricate high resolution structures with high fidelity and precision. The paper explores the various advancements in these processes in relation to their use in microfabrication and also presents the recent trends in applications like the fabrication of microlens arrays, microneedles, and tissue scaffolds.
Highlights
Provide a comprehensive overview of the different micromanufacturing techniques with a detailed focus on drop-on-demand (DOD) inkjet printing and DLP based printing.
Introduce the working principles of DOD inkjet printing and DLP printing and discuss the current status pertaining to micro fabrication.
Summarize notable applications of DOD and DLP based printing technology at micro scales.
Discuss the following challenges, limitations and offer valuable insights and prospects into the current state of DLP based and DOD inkjet printing technology.
Xingran Li et al 2024 Int. J. Extrem. Manuf. 6 042003
Over millions of years of natural evolution, organisms have developed nearly perfect structures and functions. The self-fabrication of organisms serves as a valuable source of inspiration for designing the next-generation of structural materials, and is driving the future paradigm shift of modern materials science and engineering. However, the complex structures and multifunctional integrated optimization of organisms far exceed the capability of artificial design and fabrication technology, and new manufacturing methods are urgently needed to achieve efficient reproduction of biological functions. As one of the most valuable advanced manufacturing technologies of the 21st century, laser processing technology provides an efficient solution to the critical challenges of bionic manufacturing. This review outlines the processing principles, manufacturing strategies, potential applications, challenges, and future development outlook of laser processing in bionic manufacturing domains. Three primary manufacturing strategies for laser-based bionic manufacturing are elucidated: subtractive manufacturing, equivalent manufacturing, and additive manufacturing. The progress and trends in bionic subtractive manufacturing applied to micro/nano structural surfaces, bionic equivalent manufacturing for surface strengthening, and bionic additive manufacturing aiming to achieve bionic spatial structures, are reported. Finally, the key problems faced by laser-based bionic manufacturing, its limitations, and the development trends of its existing technologies are discussed.
Highlights
Provide a comprehensive overview of laser-based bionic manufacturing technology and its applications.
Present remarkable progress in bionic manufacturing through laser subtractive manufacturing, laser equivalent manufacturing, and laser additive manufacturing.
Outline research limitations and prospects for the development of laser-based bionic manufacturing.
Hao Wang et al 2024 Int. J. Extrem. Manuf. 6 042002
Optical imaging systems have greatly extended human visual capabilities, enabling the observation and understanding of diverse phenomena. Imaging technologies span a broad spectrum of wavelengths from x-ray to radio frequencies and impact research activities and our daily lives. Traditional glass lenses are fabricated through a series of complex processes, while polymers offer versatility and ease of production. However, modern applications often require complex lens assemblies, driving the need for miniaturization and advanced designs with micro- and nanoscale features to surpass the capabilities of traditional fabrication methods. Three-dimensional (3D) printing, or additive manufacturing, presents a solution to these challenges with benefits of rapid prototyping, customized geometries, and efficient production, particularly suited for miniaturized optical imaging devices. Various 3D printing methods have demonstrated advantages over traditional counterparts, yet challenges remain in achieving nanoscale resolutions. Two-photon polymerization lithography (TPL), a nanoscale 3D printing technique, enables the fabrication of intricate structures beyond the optical diffraction limit via the nonlinear process of two-photon absorption within liquid resin. It offers unprecedented abilities, e.g. alignment-free fabrication, micro- and nanoscale capabilities, and rapid prototyping of almost arbitrary complex 3D nanostructures. In this review, we emphasize the importance of the criteria for optical performance evaluation of imaging devices, discuss material properties relevant to TPL, fabrication techniques, and highlight the application of TPL in optical imaging. As the first panoramic review on this topic, it will equip researchers with foundational knowledge and recent advancements of TPL for imaging optics, promoting a deeper understanding of the field. By leveraging on its high-resolution capability, extensive material range, and true 3D processing, alongside advances in materials, fabrication, and design, we envisage disruptive solutions to current challenges and a promising incorporation of TPL in future optical imaging applications.
Highlights
Provide a comprehensive overview of two-photon polymerization lithography (TPL)-based imaging applications.
Introduce the fundamental imaging theories, key materials properties, and fabrication technologies.
Classify and summarize the various imaging applications of TPL.
Envisage the future trends of TPL for imaging optics and offer insights on the potential solutions to current challenges.
Open all abstracts, in this tab
Yuan et al
Lightweight porous materials with high load-bearing, damage tolerance and energy absorption as well as intelligence of shape recovery after material deformation are beneficial and critical for many applications, e.g., aerospace, automobiles, electronics, etc. Cuttlebone produced in the cuttlefish has evolved vertical walls with the optimal corrugation gradient, enabling stress homogenization, significant load bearing, and damage tolerance to protect the organism from high external pressures in the deep sea. This work illustrated that the complex hybrid wave shape in cuttlebone walls, becoming more tortuous from bottom to top, creates a lightweight, load-bearing structure with progressive failure. By mimicking the cuttlebone, a novel bionic hybrid structure (BHS) was proposed, and as a comparison, a regular corrugated structure (RCS) and a straight wall structure (SWS) were designed. Three types of designed structures have been successfully manufactured by laser powder bed fusion with NiTi powder. The LPBF-processed BHS exhibited a total porosity of 0.042% and a good dimensional accuracy with a peak deviation of 17.4 μm. Microstructural analysis indicated that the LPBF-processed BHS had a strong (001) crystallographic orientation and an average size of 9.85 μm. Mechanical analysis revealed the LPBF-processed BHS could withstand over 25 000 times its weight without significant deformation and had the highest specific energy absorption value (5.32 J/g) due to the absence of stress concentration and progressive wall failure during compression. Cyclic compression testing showed that LPBF-processed BHS possessed superior viscoelastic and elasticity energy dissipation capacity. Importantly, the uniform reversible phase transition from martensite to austenite in the walls enables the structure to largely recover its pre-deformation shape when heated (over 99% recovery rate). These design strategies can serve as valuable references for the development of intelligent components that possess high mechanical efficiency and shape memory capabilities.
Gao et al
With the arrival of intelligent terminals, triboelectric nanogenerators (TENGs), as a new kind of energy converter, are considered one of the most important technologies for the next generation of intelligent electronics. As a self-powered sensor, it can greatly reduce the power consumption of the entire sensing system by transforming external mechanical energy to electricity. However, the fabrication method of triboelectric sensors largely determines their functionality and performance. This review provides an overview of various methods used to fabricate triboelectric sensors, with a focus on the processes of micro-electro-mechanical systems (MEMS) technology, three-dimensional (3D) printing, textile methods, template-assisted methods, and material synthesis methods for manufacturing. The working mechanisms and suitable application scenarios of various methods are outlined. Subsequently, the advantages and disadvantages of various methods are summarized, and reference schemes for the subsequent application of these methods are included. Finally, the opportunities and challenges faced by different methods are discussed, as well as their potential for application in various intelligent systems in the Internet of Things (IoT).
Zhang et al
The advent of the Internet of Things (IoT) has catalyzed wireless communication's evolution towards multi-band and multi-area utilization. Notably, forthcoming sixth-generation (6G) communication standards, incorporating terahertz (THz) frequencies alongside existing gigahertz (GHz) modes, drive the need for a versatile multi-band electromagnetic wave absorbing and shielding material. This study introduces a pivotal advance via a new strategy, called Ultrafast Laser-Induced Thermal-Chemical Transformation and Encapsulation of Nanoalloys (LITEN). Employing Multivariate Metal−Organic Frameworks (MTV-MOFs), this approach tailors a porous, multifunctional graphene-encased magnetic nanoalloy (GEMN). By fine-tuning pulse laser parameters and material components, the resulting GEMN excels in low-frequency absorption and THz shielding. GEMN achieves a breakthrough with a minimal reflection loss of -50.6 dB at the optimal low-frequency C-band (around 4.98 GHz). Computational evidence reinforces GEMN' efficacy in reducing radar cross sections. Additionally, GEMN demonstrates superior electromagnetic interference (EMI) shielding, reaching 98.92 dB in the THz band, with an average terahertz shielding of 55.47 dB (0.1~2THz). These accomplishments underscore GEMN's potential for 6G signal shielding. In summary, LITEN yields the remarkable EM wave controlling performance, holding promise in both GHz and THz frequency domains. This contribution heralds a paradigm shift in EM absorption and shielding materials, establishing a universally applicable framework with profound implications for future pursuits.
Li et al
Triboelectric nanogenerators (TENGs), which can efficaciously convert high entropy energy in our daily lives into electricity, are a presumable and promising micro/nano energy source to drive a profusion of sensor nodes in the era of the Internet of Things. The TENG has been attracting a great deal of research attention since its inception and has been the subject of many striking developments, including defining the fundamental physical mechanisms, expanding application scenarios, and boosting surface charge density. Particularly, manufacturing TENGs with high surface charge density is crucial to further expanding their application range and accelerating their industrialization. Here, an overview of recent advances, including material optimization, circuit design, and strategy conjunction, in fabricating TENGs with high surface charge density is provided. In these topics, different strategies are retrospected in terms of enhancement mechanisms, merits, limitations, and technological development lines. Additionally, the current challenges in high-performance TENG research and the orientation of future endeavors in this field are discussed, which may shed new light on the next stage of TENG development.
Xu et al
Exsolution, as an effective approach to construct particle-decorated interfaces, is still challenging to yield interfacial films rather than isolated particles. Inspired by in vivo near infrared laser photothermal therapy (PTT), using 3 mol.% Y2O3 stabilized tetragonal zirconia polycrystals (3Y-TZP) as host oxide matrix and iron-oxide (Fe3O4/γ-Fe2O3/α-Fe2O3) materials as photothermal modulator and exsolution resource, femtosecond laser ultrafast exsolution approach is presented enabling to conquer this challenge. The key is to trigger photothermal annealing behavior via femtosecond laser ablation to initialize phase transition into tetragonal zirconia (t-ZrO2) and induce columnar crystal growth, where Fe-ions rapidly segregate along grain boundaries and diffuse towards the outmost surface, becoming "frozen" there, highlighting the potential to use photothermal materials and ultrafast heating/quenching behaviors of femtosecond laser ablation for interfacial modification via exsolution. Triggering interfacial iron-oxide coloring exsolution is composition and concentration dependent, indicating photothermal materials themselves and corresponding photothermal transition capacity play a crucial role, initializing at 5wt%, 2wt%, and and 3wt% for Fe3O4-/γ-Fe2O3/α-Fe2O3 embedded 3Y-TZP samples. Due to different photothermal effects, exsolution states of ablated 5wt% Fe3O4-/γ-Fe2O3/α-Fe2O3-embedded 3Y-TZP samples are completely different, complete coverage, exhaustion (ablated away) and partial exsolution (rich in the crystal boundaries of sublayers). This novel exsolution is uniquely featured by up to now the deepest microscale (10 μm from 5 wt%-Fe3O4-3Y-TZP sample) Fe-elemental deficient layer for exsolution and the whole coverage of exsolved materials rather than formation of isolated exsolved particles by other methods. It is believed that femtosecond laser ultrafast photothermal exsolution may pave a good way to modulate interfacial properties for extensive applications in the fields of biology, optics/photonics, energy, catalysis, environment, etc.