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3D printing, a rapidly expanding domain of additive manufacturing, enables the fabrication of intricate 3D structures with adjustable fabrication parameters and scalability. Nonetheless, post‐fabrication, 3D‐printed materials often require an activation step to eliminate non‐conductive polymers, a process traditionally achieved through chemical, thermal, or electrochemical methods. These conventional activation techniques, however, suffer from inefficiency and inconsistent results. In this study, a novel chemical‐free activation method employing laser treatment is introduced. This innovative technique effectively activates 3D‐printed electrodes, which are then evaluated for their photo and electrochemical performance against traditional solvent‐activated counterparts. The method not only precisely ablates surplus non‐conductive polymers but also exposes and activates the underlying electroactive materials. The 3D‐printed electrodes, processed with this single‐step laser approach, exhibit a notably low overpotential of ≈505 mV at a current density of −10 mA cm−2 under an illumination wavelength of 365 nm. These electrodes also demonstrate exceptional durability, maintaining stability through >100 000 cycles in energy storage applications. By amalgamating 3D printing with laser processing, the creation of electrodes with complex structures and customizable properties is enabled. This synergy paves the way for streamlined production of such devices in the field of energy conversion and storage. [ABSTRACT FROM AUTHOR]

In the field of questioned document examination, determining the sequence of intersecting lines is still a technical challenge. This study aims to validate whether confocal Raman spectroscopy can determine the sequence of intersecting lines created by laser prints toner and seal ink through empirical research. The study collected 110 varieties of seal ink and 1074 test pages from 66 models of laser printers available in the Chinese market. Based on the Raman spectral characteristics of the seal ink and the microscopic morphology of the toner, 13 types of seal ink and three types of laser printers were selected for further analysis, producing 78 representative samples of intersecting lines. Confocal Raman spectroscopy was applied to the examination of these samples using a point‐scanning mode for enhanced accuracy and efficiency. The experimental results demonstrate that confocal Raman spectroscopy can non‐destructively and quickly examine the sequence of intersecting lines produced by laser printer toner and seal ink. Variations in toner forms result in differing levels of difficulty in resolving intersection problems, with the sequence of intersecting lines from toner‐dense laser printers being the easiest to ascertain. In contrast, those from printers with porous and dispersed toner present a more significant challenge in examination. This study can be corroborated with other methods proposed, and more significantly, it lays the groundwork for addressing intersection problems related to other printing or writing instruments. [ABSTRACT FROM AUTHOR]

In Laser decal transfer process, the materials are printed in micron-sized dots without changing its phase from thin film coated substrate (donor substrate). The pulsed laser irradiates the donor substrate opposite to the coated side and transfers the material in the same phase to another substrate kept very close to the donor substrate. The process has shown its potential for printing microsensors without any changes in physical and functional properties during the printing process for the electronics components. Generally, ZnO-based patterned structure is still challenging for the existing manufacturing techniques without hampering its functionality in the sensing application. In this work, an attempt has been made to print ZnO structure in solid phase using maskless µ-3D printing using a long-pulsed CO2 laser. A two-dimensional numerical model in COMSOL Multiphysics is developed to estimate the temperature induced by the laser irradiation on the sacrificial layer, and energy conservation is applied to estimate the particle's velocity. A deformed mesh geometry is used to predict the ablation depth of the sacrificial layer after the laser irradiation. The deformed geometry shows the ablated area in the sacrificial layer, and the temperature induces a different time frame. The ZnO ceramic film is coated on the sacrificial layer followed by the laser µ-3D printing of ZnO on silicon wafer using CO2 laser at three laser fluence, i.e., 530 mJ/cm2, 1030 mJ/cm2, and 1530 mJ/cm2 with 90% pulse overlap. The ejection of ZnO from substrate is visualized using a high-speed camera by shadowgraphy techniques. The ejection mode is defined based on the deviation of the particle from the laser beam direction. [ABSTRACT FROM AUTHOR]

As is well known, Laser print paper is usually produced with high‐quality chemical wood pulp. The laser print waste paper fiber (LPWF) is a high‐quality secondary fiber, and the research and development of high‐value utilization technology for laser print waste paper has attracted much attention in the field of renewable resource recycling. In this study, LPWF was used to reinforce poly(lactic acid) (PLA) composites in the field, and the composites were modified with bioenzyme, cationic polyacrylamide (CPAM), and nano‐silicon carbide (Nano‐SiC) to enhance the interfacial compatibility of LPWF/PLA composites. The study systematically investigated the effects of various modification methods on the characteristics and degradability of composites made from laser print waste paper fiber reinforced PLA resin matrix. The results showed that the mechanical properties of the composites treated with CPAM and Nano‐SiC were significantly improved, with tensile strengths of 54.3 and 59.5 MPa, and flexural strengths of 85.1 and 91.5 MPa, respectively, and the water absorption of the composites was reduced after the modification treatment, while the thermal stability was improved. The degradation performance of the composites in various water environments indicated that the inclusion of LPWF accelerated the water degradation rate of the composites, with the maximum degradation rate of the composite reaching 1.26% in 30 days. Highlights: Laser print waste paper is an excellent quality recyclable fiber resource.Four modifiers were used to modify LPWF/PLA composites.Characteristics and degradability of the composites were investigated.Significantly improved properties of CPAM and Nano‐SiC modified composites.The degradation rate of composites is increased by the addition of LPWF. [ABSTRACT FROM AUTHOR]

This study explores the optimization of fused deposition modeling (FDM), a prominent 3D printing technology known for its accessibility and cost-effectiveness. The research aimed to identify and reduce errors associated with key printing parameters, specifically the layer height, printing temperature, and printing speed. Advanced tools such as a Keyence laser scanner and microscope were used to evaluate the dimensional accuracy and surface quality of various samples. The results indicate that the optimal settings for the layer height (0.16 mm), printing temperature (250 °C), and printing speed (350 mm/s) significantly minimize variation, resulting in more consistent and accurate prints. The results also showed that the samples printed with these optimized parameters had the lowest variability, underscoring the critical importance of precisely managing these factors. The findings highlight the critical role of fine-tuned FDM parameters in improving the quality and reliability of printed objects and provide valuable insights for further advances in 3D printing processes. [ABSTRACT FROM AUTHOR]

Vertical-cavity surface-emitting lasers (VCSELs) are essential for exhibiting single-transverse-mode output characteristics, which are critical for applications in quantum sensing, optical interconnection, and laser printing. In this study, we achieved stable single-transverse-mode lasing using extended-2λ-cavity with an oxide aperture diameter of 7.08 μm. The device demonstrated a high output power of 6.8 mW and a narrow linewidth of 49.8 MHz at room temperature. Additionally, it maintained stable single-mode emission at 794.8 nm and achieved a side-mode suppression ratio (SMSR) exceeding 40 dB within the temperature range of 25 °C~85 °C, thereby meeting the requirements of 87Rb atom quantum sensors. The fabricated device obtained high-power and narrow linewidth single-transverse-mode operation by a monolithic extended cavity without introducing additional processing procedures, which is expected to promote the commercial viability of VCSELs in quantum sensing. [ABSTRACT FROM AUTHOR]

Flexible regulation of local chemistry and band gap of perovskite quantum dots (PeQDs) is crucial for exploring their new functionalities and device applications. In this work, a strategy based on the combination of femtosecond (fs) laser‐irradiation and thermal treatment to effectively manipulate chemical composition and emitting wavelength of PeQDs in amorphous glass, is reported. The engineering of ultrafast laser‐induced thermal effect enables to induce in situ nucleation/growth of dual‐phase PeQDs within an individual glass matrix. By elevating heat‐treatment (HT) temperature, I− ions are driven to surmount the diffusion barrier into the PeQDs lattice, leading to a tunable emission wavelength ranging from 613 to 647 nm. Besides, it is verified that the temperature‐dependent diffusion rate of I− ions plays a pivotal role in affecting luminescent efficiency and color of the dual‐phase glass. Finally, fs laser direct writing of multi‐color patterns is presented, which provides a flexible method to develop new encryption/decryption technology for information security and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

Liquid crystalline (LC) materials are especially suited for the preparation of active three-dimensional (3D) and 4D microstructures using two-photon laser printing. To achieve the desired actuation, the alignment of the LCs has to be controlled during the printing process. In most cases studied before, the alignment relied on surface modifications and complex alignment patterns and concomitant actuation were not possible. Here, we introduce a strategy for spatially aligning LC domains in three-dimensional space by using 3D-printed polydimethylsiloxane-based microscaffolds as confinement barriers, which induce the desired director field. The director field resulting from the boundary conditions is calculated with Landau de Gennes theory and validated by comparing experimentally measured and theoretically predicted birefringence patterns. We demonstrate our procedures for structures of varying complexity and then employed them to fabricate 4D microstructures that show the desired actuation. Overall, we obtain excellent agreement between theory and experiment. This opens the door for rational design of functional materials for 4D (micro)printing in the future. [ABSTRACT FROM AUTHOR]

A novel laser thermal printing technique toward the fabrication of all‐in‐one flexible intelligent devices is presented in this work, addressing the existing challenges in their scalable manufacturing and multifunctional performance. The first‐ever application of this technique for the synthesis of a multifunctional intelligent cobweb structure is presented. The resultant cobweb integrates a conductive network of multi‐walled carbon nanotubes (MWCNTs) and NdFeB magnetic microparticles within a polydimethylsiloxane (PDMS) matrix, enabling seamless incorporation of sensing, stimulus response, and actuation functionalities. The cobweb exhibits multifunctional sensing characteristics, including a 2.37 strain gauge factor and a 0.312%·mT−1 magnetic field sensitivity, excellent stability exceeding 3500 cycles. Furthermore, the cobweb achieves accurate capture of a beetle on the basis of real‐time sensing of the beetle, verifying its rapid stimulus response characteristics. Meanwhile, the cobweb exhibits an electromagnetic ejection performance with an ejection height of over 33.5 times the size of the projectile, verifying its powerful actuating ability. These results demonstrate the successful integration of multifunctional sensing, stimulus response, and actuation within the cobweb structure, facilitated by the innovative laser thermal printing process. The laser thermal printing technique marks a significant advancement in the efficient fabrication of miniaturized and multifunctional flexible intelligent devices based on thermosetting materials. [ABSTRACT FROM AUTHOR]

We report an anomalous structural transformation of a Cu(I) cluster into two different types of copper‐silver (CuAg) alloy nanoclusters. Different from previous reports, we demonstrate that under specifically designed reaction conditions, the Ag‐doping could induce a substantial growth of the starting Cu15 and a Ag13Cu20 nanocluster was obtained via the unexpected insertion of an Ag13 kernel inside the Cu(I)‐S shell. Ag13Cu20 demonstrates high activity to initiate the photopolymerization of previously hard‐to‐print inorganic polymers in 3D laser microprinting. Interestingly, a slight modification of the reaction condition leads to the formation of another Ag18‐xCuxS (8≤x) nanocluster templated by a central S2− anion, which possesses a unique electronic structure compared to conventional template‐free CuAg nanoclusters. Overall, this work unveils the intriguing doping chemistry of Cu clusters, as well as their capability to create different types of alloy nanoclusters with previously unobtainable structures and multifunctionality. [ABSTRACT FROM AUTHOR]

Photonic integrated circuits (PICs) are iterating on electronic ones to enable higher‐speed parallel computing while meeting the growing demands for energy efficiency in big‐data processing. However, manufacturing multi‐layered and 3D PICs remains challenging based on conventional planar lithography. Here, a rapid prototyping technique is delineated to configure large‐area and 3D PIC in glass based on laser‐direct written optical waveguides by employing femtosecond cylindrically polarized vortex laser beams. The vortex laser beam is mathematically rotationally invariant and capable of conformally transforming waveguide cross‐sections at arbitrary bending angles of 0–90° and across a large depth change. Based on this approach, a one‐layer 12‐core waveguide circuit with a variable cross‐section (diameter 5–11.5 µm) while maintaining a high mode ellipticity >0.974, as well as a more complex three‐layer 36‐core connector in which the waveguide dives continuously from 50 µm to 550 µm with a small loss difference of <0.1 dB is demonstrated. This work offers a pathway for 3D imprinting of large‐area photonic circuits in glass and other transparent materials, which has potential applications in high‐efficiency photonic computing, multidimensional quantum networks, and 3D optics topology. [ABSTRACT FROM AUTHOR]

Phase transition at the initial solidification stage notably affects subsequent phase structure of peritectic alloys, however, detailed dynamics between entangled three-phase region remains ambiguous in the far-from-equilibrium condition during laser additive manufacturing. Here, in-situ peritectic phase transition during single-layer laser printing of an exemplary 304L stainless steel is directly investigated and quantified at high temporospatial resolution by high-speed synchrotron X-ray diffraction and imaging. These quantitative observations clarify the mechanism of coupled peritectic growth and local remelting at three-phase region. The results revealed provide in-depth understanding of phase transformation dynamics and delicate design of phase structure for metal additive manufacturing. [ABSTRACT FROM AUTHOR]

Hard X‐rays are needed for non‐destructive nano‐imaging of solid matter. Synchrotron radiation facilities (SRF) provide the highest‐quality images with single‐digit nm resolution using advanced techniques such as X‐ray ptychography. However, the resolution or field of view is ultimately constrained by the available coherent flux. To address this, the beam's incoherent fraction can be exploited using multiple parallel beams in an X‐ray multibeam ptychography (MBP) approach. This expands the domain of X‐ray ptychography to larger samples or more rapid measurements. Both qualities favor the study of complex composite or functional samples, such as catalysts, energy materials, or electronic devices. The challenge of performing ptychography at high energy and with many parallel beams must be overcome to extract the full advantages for extended samples while minimizing beam attenuation. Here, that challenge is overcome by creating a lens array using cutting‐edge laser printing technology and applying it to perform scanning with MBP with up to 12 beams and at photon energies of 13 and 20 keV. This exceeds the measurement limits of conventional hard X‐ray ptychography without compromising image quality for various samples: Siemens star test pattern, Ni/Al2O3 catalyst, microchip, and gold nano‐crystal clusters. [ABSTRACT FROM AUTHOR]

Multi‐photon 3D laser printing has gathered much attention in recent years as a means of manufacturing biocompatible scaffolds that can modify and guide cellular behavior in vitro. However, in vivo tissue engineering efforts have been limited so far to the implantation of beforehand 3D printed biocompatible scaffolds and in vivo bioprinting of tissue constructs from bioinks containing cells, biomolecules, and printable hydrogel formulations. Thus, a comprehensive 3D laser printing platform for in vivo and in situ manufacturing of microimplants raised from synthetic polymer‐based inks is currently missing. Here, a platform for minimal‐invasive manufacturing of microimplants directly in the organism is presented by one‐photon photopolymerization and multi‐photon 3D laser printing. Employing a commercially available elastomeric ink giving rise to biocompatible synthetic polymer‐based microimplants, first applicational examples of biological responses to in situ printed microimplants are demonstrated in the teleost fish Oryzias latipes and in embryos of the fruit fly Drosophila melanogaster. This provides a framework for future studies addressing the suitability of inks for in vivo 3D manufacturing. The platform bears great potential for the direct engineering of the intricate microarchitectures in a variety of tissues in model organisms and beyond. [ABSTRACT FROM AUTHOR]

Holographic femtosecond laser printing technology is widely used in the fabrication of micropatterns because of its high efficiency and flexibility. However, speckle noise and energy fluctuations limit the quality of the printed structure. In this study, an improved complex‐amplitude modulation holographic femtosecond laser printing method for high‐quality micropattern fabrication is proposed. The holographic light field is divided into a signal area and a surrounding noise area. To improve laser uniformity, phase modulation is applied in the signal region to eliminate the speckle noise caused by unconstrained phase interference, and weighted amplitude modulation is introduced in the signal area to improve the calculation accuracy. To precisely control laser energy density, weighted energy efficiency modulation is introduced in the noise region to disperse the energy that exceeds the material damage threshold. Under the synergistic control of laser uniformity and energy density, high‐quality micro‐pattern structures are printed efficiently. A high‐quality millimeter‐sized multifocal zone plate with micron accuracy is fabricated with the splicing printing method, demonstrating the potential of micropattern processing and the fabrication of functional devices such as binary optics. [ABSTRACT FROM AUTHOR]

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The concept of personalized medicine tailored to individual patients has garnered considerable attention recently, particularly in exploring the potential of 3D printing technology within the pharmaceutical and healthcare industries. 3D printing involves the layer-by-layer creation of threedimensional objects from digital designs. This review aim to provide an in-depth discussion focusing on 3D printing technology, its role in drug delivery systems, and its application in the pharmaceutical product development process. Commonly categorized by material layering methods, 3D printers typically fall into inkjet, extrusion, or laser-based systems. The review delves into these different types of 3D printers and their diverse applications in drug delivery across various sectors. Additionally, it encompasses a selection of recent research conducted in the pharmaceutical realm concerning 3D printing for drug delivery applications and challenges. [ABSTRACT FROM AUTHOR]

Traditional approaches to modular construction progress monitoring and quality control with stringent and tight tolerances for on-site and off-site assembly processes are usually based on 3D laser scanning, but the high equipment costs associated with acquiring point clouds have economic ramifications. This paper provides the details of a new and inexpensive method through the integration of AprilTags and an ordinary phone. By using AprilTags instead of QR codes to label modules, progress management is achieved through the rapid identification and association of multiple modules based on a single image. Moreover, a virtual multi-view vision algorithm based on AprilTags is proposed to generate 3D reverse models of the construction site; the quality result can be acquired by comparing the offset and rotation values of the reverse model and the BIM model. Finally, all the algorithms are validated through comparing the reverse models with the reference models made with 3D printing and 3D laser scanning, which verifies the accuracy and efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

Recent technological advancements, such as portable electronics and electric vehicles, have created a pressing need for more efficient energy storage solutions. Lithium‐ion batteries (LIBs) have been the preferred choice for these applications, with graphite being the standard anode material due to its stability. However, graphite falls short of meeting the growing demand for higher energy density, possessing a theoretical capacity that lags behind. To address this, researchers are actively seeking alternative materials to replace graphite in commercial batteries. One promising avenue involves lithium‐alloying materials like silicon and phosphorus, which offer high theoretical capacities. Carbon–silicon composites have emerged as a viable option, showing improved capacity and performance over traditional graphite or pure silicon anodes. Yet, the existing methods for synthesizing these composites remain complex, energy‐intensive, and costly, preventing widespread adoption. A groundbreaking approach is presented here: the use of a laser writing strategy to rapidly transform common organic carbon precursors and silicon blends into efficient "graphenic silicon" composite thin films. These films exhibit exceptional structural and energy storage properties. The resulting three‐dimensional porous composite anodes showcase impressive attributes, including ultrahigh silicon content, remarkable cyclic stability (over 4500 cycles with ∼40% retention), rapid charging rates (up to 10 A g−1), substantial areal capacity (>5.1 mAh cm−2), and excellent gravimetric capacity (>2400 mAh g−1 at 0.2 A g−1). This strategy marks a significant step toward the scalable production of high‐performance LIB materials. Leveraging widely available, cost‐effective precursors, the laser‐printed "graphenic silicon" composites demonstrate unparalleled performance, potentially streamlining anode production while maintaining exceptional capabilities. This innovation not only paves the way for advanced LIBs but also sets a precedent for transforming various materials into high‐performing electrodes, promising reduced complexity and cost in battery production. [ABSTRACT FROM AUTHOR]

In this study, the evolution of grain and ripple structures on the surface of 6061 aluminum alloy (AA6061) parts fabricated by a laser-foil-printing (LFP) additive manufacturing process at different preheated temperatures were characterized and compared. Results indicated that the preheated temperature of the substrate plays a crucial role in the formation of grain structures, the shape of ripples, and the surface quality of aluminum parts fabricated by LFP. As the preheated temperature of the substrate elevated from room temperature to 300 °C, the grain and ripple structures formed coarser and flatter, respectively, due to the reduction in the thermal gradient and cooling rate. The grain structure was coarsened with an increasing average grain size from 74.96 to 150.5 μm measured by the electron backscattered diffraction (EBSD) technique. Meanwhile, the ripple structure was stretched and transformed from short and curved shapes to smoother, which improved the surface roughness significantly and reduced the Sa value from 21.7 to 8.5 μm in three-dimensional (3D) surface morphologies. However, when the preheated temperature reached 500 °C in LFP, the grain structure experienced a recrystallization process, resulting in the formation of finer grains compared to those observed at 300 °C. Furthermore, the surface quality was improved to a Sa value of 5.2 μm because the flowability of the melt pool was enhanced from the extended solidification time by the smallest temperature gradient and cooling rate at the highest preheat temperature, which was estimated using the finite element method (FEM). In the X-ray diffraction (XRD) patterns, the ratio of the main peak (200) to the secondary peak was gradually increased when preheated temperature elevated; however, the ratio decreased at 500 °C due to the recrystallization. [ABSTRACT FROM AUTHOR]

Development of high‐performance photoinitiator is the key to enhance the printing speed, structure resolution and product quality in 3D laser printing. Here, to improve the printing efficiency of 3D laser nanoprinting, we investigate the underlying photochemistry of gold and silver nanocluster initiators under multiphoton laser excitation. Experimental results and DFT calculations reveal the high cleavage probability of the surface S−C bonds in gold and silver nanoclusters which generate multiple radicals. Based on this understanding, we design several alkyl‐thiolated gold nanoclusters and achieve a more than two‐orders‐of‐magnitude enhancement of photoinitiation activity, as well as a significant improvement in printing resolution and fabrication window. Overall, this work for the first time unveils the detailed radical formation pathways of gold and silver nanoclusters under multiphoton activation and substantially improves their photoinitiation sensitivity via surface engineering, which pushes the limit of the printing efficiency of 3D laser lithography. [ABSTRACT FROM AUTHOR]

Porous SiC ceramics are preferable materials for industrial applications such as hot gas filtration and microfiltration, some areas of fine filtration exist where complex structures of ceramic components are required. In this study, a novel method was employed for preparing high‐flux ceramic membranes via selective laser printing. The powder used for laser printing is a laboratory‐prepared polysiloxane powder, which can be pyrolyzed under relatively lower temperatures to obtain SiOC ceramic membranes. From the results of characterization and testing, the obtained ceramic membranes exhibited inimitable pore microstructure, high porosity, and outstanding filtering performance. Laser printing demonstrated good potential to be a strong candidate for the next generation of ceramic membrane fabrication technology. [ABSTRACT FROM AUTHOR]

Achieving 3D-printed Ti6Al4V alloy with customized microstructures and mechanical characteristics remains challenging, wherein the processing efficiency mainly depends on the laser energy, mass deposition rate, and duration. Based on these factors, a simple and eco-friendly direct laser metal deposition approach was followed to get 3D-printed Ti6Al4V alloys at various laser powers (300–500 W). Herein, a 1.5-kW continuous fiber laser with a wavelength of 1080 nm was used to create a stable and dense alloy. The obtained 3D-printed specimens were characterized to assess the laser power–dependent microstructures, compositions, microhardness, grain sizes, color filling, and dimensional stability in terms of height/width. FESEM micrographs of the obtained alloys revealed the existence of porous spherical grains of mean size in the range of 50–81 μm. The alloy deposited at 300 W and 0.495 mm/s scan speed displayed the maximum hardness (excellent bong strength) value of 859.2 HV0.5 devoid of any crack and porosity. XRD patterns of the alloy revealed the existence of α + β martensitic phase transformation which is responsible for the marginal increase of hardness. It is asserted that the proposed 3D-printed Ti6Al4V alloy can be beneficial for the development of efficient structural parts desired for diverse applications. [ABSTRACT FROM AUTHOR]

Applied Materials, Inc. has reported a novel and manufacturable microLED display architecture, featuring UV‐A microLEDs, 4‐subpixel layout, pixel isolation wells filled with inkjetted Cd‐free R/G/B quantum dots (QDs), and a blanket UV blocker on top. A 1.37" smart‐watch active‐matrix display prototype was assembled using such method. Our QDs, including blue QD and the matrix materials exhibit excellent stability under UV excitation, as verified by accelerated lifetime test under higher UV flux and elevated temperature. The emission properties of our R/G/B QDs was further optimized, paving a path to achieve 99% DCI‐P3 color space coverage. Our display demonstrates a highly uniform Lambertian emission pattern with minimal color shift at high viewing angles, attributing to all emissions originating from QD embedded in the same polymer matrix. Furthermore, we can eliminate the QD photon‐brightening effect and demonstrate display with high thermal stability up to 90⁰C. [ABSTRACT FROM AUTHOR]

In nature, structural and functional materials often form programmed three-dimensional (3D) assembly to perform daily functions, inspiring researchers to engineer multifunctional 3D structures. Despite much progress, a general method to fabricate and assemble a broad range of materials into functional 3D objects remains limited. Herein, to bridge the gap, we demonstrate a freeform multimaterial assembly process (FMAP) by integrating 3D printing (fused filament fabrication (FFF), direct ink writing (DIW)) with freeform laser induction (FLI). 3D printing performs the 3D structural material assembly, while FLI fabricates the functional materials in predesigned 3D space by synergistic, programmed control. This paper showcases the versatility of FMAP in spatially fabricating various types of functional materials (metals, semiconductors) within 3D structures for applications in crossbar circuits for LED display, a strain sensor for multifunctional springs and haptic manipulators, a UV sensor, a 3D electromagnet as a magnetic encoder, capacitive sensors for human machine interface, and an integrated microfluidic reactor with a built-in Joule heater for nanomaterial synthesis. This success underscores the potential of FMAP to redefine 3D printing and FLI for programmed multimaterial assembly. A freeform multimaterial assembly process (FMAP) is demonstrated, synchronizing laser induction with 3D printing for seamlessly integrating multimaterials into 3D objects, enabling streamlined, flexible, and precise electronic device fabrication. [ABSTRACT FROM AUTHOR]

The field of bioelectronics with the aim to contact cells, cell clusters, biological tissues and organoids has become a vast enterprise. Currently, it is mainly relying on classical micro‐ and nanofabrication methods to build devices and systems. Very recently the field is highly pushed by the development of novel printable organic, inorganic and biomaterials as well as advanced digital printing technologies such as laser and inkjet printing employed in this endeavor. Recent advantages in alternative additive manufacturing and 3D printing methods enable interesting new routes, in particular for applications requiring the incorporation of delicate biomaterials or creation of 3D scaffold structures that show a high potential for bioelectronics and building of hybrid bio‐/inorganic devices. Here the current state of printed 2D and 3D electronic structures and related lithography techniques for the interfacing of electronic devices with biological systems are reviewed. The focus lies on in vitro applications for interfacing single cell, cell clusters, and organoids. Challenges and future prospects are discussed for all‐printed hybrid bio/electronic systems targeting biomedical research, diagnostics, and health monitoring. [ABSTRACT FROM AUTHOR]

A theoretical paper based on chiral micropolar effective‐medium theory suggested the possibility of unusual roton‐like acoustical‐phonon dispersion relations in 3D elastic materials. Here, as a first novelty, the corresponding inverse problem is solved, that is, a specific 3D chiral elastic metamaterial structure is designed, the behavior of which follows this effective‐medium description. The metamaterial structure is based on a simple‐cubic lattice of cubes, each of which not only has three translational but also three rotational degrees of freedom. The additional rotational degrees of freedom are crucial within micropolar elasticity. The cubes and their degrees of freedom are coupled by a chiral network of slender rods. As a second novelty, this complex metamaterial is manufactured in polymer form by 3D laser printing and its behavior is characterized experimentally by phonon‐band‐structure measurements. The results of these measurements, microstructure finite‐element calculations, and solutions of micropolar effective‐medium theory are in good agreement. The roton‐like dispersion behavior of the lowest phonon branch results from two aspects. First, chirality splits the transverse acoustical branches as well as the transverse optical branches. Second, chirality leads to an ultrastrong coupling and hybridization of chiral acoustical and optical phonons at finite wavevectors. [ABSTRACT FROM AUTHOR]

Direct ablation-free femtosecond laser printing has been used to fabricate a metasurface in the form of ordered arrays of hollow nanobumps on the surface of a thin gold film. Resonant dips in the reflection spectra of fabricated metasurfaces, as well as a resonant increase in the third-harmonic intensity by two orders of magnitude, at the spectral matching of the observed optical resonances of the structure and the pump wavelength of the fundamental harmonic indicate that such ordered nanostructures allows the existence of high-Q-factor collective plasmon resonances, which are associated with the excitation and destructive interference of plasmon-polariton waves. [ABSTRACT FROM AUTHOR]

Biological activities take place in 3D environments, where cells interact in various directions in a defined, often microstructured, space. A sub‐millimeter‐sized stretching device is developed to mechanically stimulate a structurally restricted, soft multicellular microenvironment to investigate the effect of defined cyclic mechanical forces on a multicellular system. It consists of a multi‐material 3D microstructure made of Polydimethylsiloxane (PDMS) and gelatine‐based hydrogel, which is printed using the 2‐photon polymerization (2PP) method. The printed structures are first characterized microscopically and mechanically to study the effect of different printing parameters. Using 2PP, organotypic cell cultures are then directly printed into the hydrogel structures to create true 3D cell culture systems. These systems are mechanically stimulated with a cantilever by indenting at defined positions. The cells in the 3D organotypic cell culture change morphology and actin orientation when exposed to cyclic mechanical stretch, even within short timescales of 30 min. As proof of concept, a Medaka retinal organoid is encapsulated in the same structure to demonstrate that even preformed organoids can be stimulated by this method. The results highlight the capability of 2PP for manufacturing multifunctional soft devices to mechanically control multicellular systems at micrometer resolution and thus mimic mechanical stresses as they occur in vivo. [ABSTRACT FROM AUTHOR]

This work proposes an original method for tailoring the microstructure and electrical properties of Ni/GDC anodes by using 3D inkjet printing of high-viscosity functional compositions with intermediate laser treatment of each layer after each printing pass. Based on a mixture of highly dispersed oxides NiO and CeO 2 doped with gadolinium (GDC), paste formulations for 3D inkjet printing have been developed. The effects of 3D printing and laser treatment conditions on the porosity and shrinkage ratio of the NiO/GDC anodes during sintering were investigated. The reduction of the anode support workpieces to produce Ni/GDC cermet was carried out and the effect of laser exposure on the morphology and electrical characteristics of the resulting samples was studied. It was found that an increase in the laser exposure values during layer-by-layer laser treatment of printing compositions leads to a two-fold increase in the porosity of the solid oxide fuel cell components, an increase in the average pore size from 0.2 to 0.3 to 2–5 μm, and to a five-fold decrease in the sintering shrinkage ratio. It was also found that the electrical conductivity of the Ni/GDC cermet, produced by the reduction of the laser treated NiO/GDC, increased by 5–10 times as the laser exposure values increased. The influence mechanism of the layer-by-layer laser treatment of the original NiO/GDC samples on the electrical conductivity of their reduced counterparts, Ni/GDC cermet anodes, has been proposed. An increase in the electrical conductivity was shown to be due to in situ reduction of NiO, partial sintering of Ni nanoparticles and the formation of a percolation network. This new method of hybrid 3D printing opens up great prospects for tailoring the morphological and electrical characteristics of SOFC anode supports. [ABSTRACT FROM AUTHOR]

Resin-bonded bridges (RBBs) are a minimally invasive and aesthetically pleasing treatment modality. However, their frequent failure has posed challenges for both dental professionals and patients. This necessitates the exploration of innovative strategies to enhance the longevity of RBBs. This study aimed to assess the bond strength of a mesh bridge fabricated using computer-aided design and three-dimensional (3D) printing technology in comparison to the traditional aluminum oxide sandblasting method. A total of 48 lower incisors were embedded in acrylic bases according to a standardized computer-generated model to receive 24 metal RBBs. The two groups underwent distinct metal surface treatments: the 3D mesh novel design and sandblasting with aluminum oxide particles sized at 250.00 µm. The bond strength of the bridges was evaluated, and statistical analysis was performed using the independent samples t-test with a significance level set at α = 0.05. The findings revealed a significant difference between the two methods (p < 0.001). The 3D mesh design exhibited a mean bond strength of 387.89 ± 24.15 N, while the sandblasting technique yielded a mean value of 161.46 ± 31.25 N. In summary, the 3D mesh design substantially enhanced the bond strength of RBBs compared to the traditional sandblasting technique. [ABSTRACT FROM AUTHOR]

Nanofabrication technologies significantly influence the development of modern optical science. One of such technologies is laser‐induced transfer, which allows the creation of single Mie‐resonant spherical particles on a wide range of substrates. This study shows that this method can provide asymmetric dimers at the output: a single femtosecond pulse being focused on a silicon‐on‐insulator wafer results in appearing two nearly spherical particles of different sizes. The resulting dimers are characterized by scanning electron microscopy, elastic light scattering and Raman spectroscopy to gain insight into their structural properties. Back focal plane imaging and variable‐color evanescent‐wave illumination are then employed to measure the light scattering patterns from isolated dimers. Due to the interference of the excited resonances, the observed patterns are strongly asymmetric in a range of visible wavelengths, which is consistent with theoretical predictions. The results demonstrate the potential of asymmetric silicon dimers made by single‐shot laser‐induced transfer for color routing at visible light. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to present the fabrication of 6061 aluminum alloy (AA6061) using a promising laser additive manufacturing process, called the laser-foil-printing (LFP) process. The process window of AA6061 in LFP was established to optimize process parameters for the fabrication of high strength, dense and crack-free parts even though AA6061 is challenging for laser additive manufacturing processes due to hot-cracking issues. Design/methodology/approach: The multilayers AA6061 parts were fabricated by LFP to characterize for cracks and porosity. Mechanical properties of the LFP-fabricated AA6061 parts were tested using Vicker's microhardness and tensile testes. The electron backscattered diffraction (EBSD) technique was used to reveal the grain structure and preferred orientation of AA6061 parts. Findings: The crack-free AA6061 parts with a high relative density of 99.8% were successfully fabricated using the optimal process parameters in LFP. The LFP-fabricated parts exhibited exceptional tensile strength and comparable ductility compared to AA6061 samples fabricated by conventional laser powder bed fusion (LPBF) processes. The EBSD result shows the formation of cracks was correlated with the cooling rate of the melt pool as cracks tended to develop within finer grain structures, which were formed in a shorter solidification time and higher cooling rate. Originality/value: This study presents the pioneering achievement of fabricating crack-free AA6061 parts using LFP without the necessity of preheating the substrate or mixing nanoparticles into the melt pool during the laser melting. The study includes a comprehensive examination of both the mechanical properties and grain structures, with comparisons made to parts produced through the traditional LPBF method. [ABSTRACT FROM AUTHOR]

State‐of‐the‐art 3D two‐photon laser printing systems already use pre‐compensation algorithms to reduce systematic deviations between the printed and the targeted structures. Nevertheless, the remaining deviations are often still larger than the uncontrollable or "statistical" deviations. In principle, it is straightforward to correct for systematic deviations by measuring the difference between printed structure and target and by subtracting the difference from the first target to obtain the next‐iteration target. However, in reality, one faces several issues such as noise and systematic errors of the characterization measurement itself, as well as unwanted translations and rotations between the coordinate systems of the characterization setup and the printer, respectively. Two examples of printed structures requiring sub‐micrometer accuracy are considered, a large 1D micro‐lens array and a specific diffractive optical element. For both, the device performance before the pre‐compensation workflow described herein is insufficient for the targeted application and has become sufficient after this workflow. The workflow involving optimizations using cross‐correlations with confocal‐optical‐microscopy data is documented by an open‐access program (available via GitLab). This program includes an easy‐to‐use graphical user interface so that other researchers can immediately profit from it. [ABSTRACT FROM AUTHOR]

As a novel surface treatment technology, in-situ laser polishing aims to improve surface finish of 3D printed parts, while laying the foundation for the integrated processing of 3D printing and laser polishing. However, the polishing process will introduce a few new surface structures (undercuts, step structures, ripples, etc.), which will affect the surface roughness. In this work, the surface roughness and surface structure after high power and low power polishing were compared respectively through experiments. In addition, a 2D transient numerical model was developed to explore the forming mechanism of different structures. The evolution of temperature field, velocity field and freedom surface of melting pool under different parameters were analyzed by the model. The results showed that the solidification induced surface structure with large roughness was generated after high power polishing. During its formation, the thermocapillary force was dominant and drove the tangential flow of fluid. While, low power polishing resulted in ripple structure with small roughness. The emergence of this structure was primarily due to the capillary force as the leading force in the melting pool flow process, which drove the normal flow of the melt, thus eliminating the large surface curvature. Furthermore, the width of the melting pool in the simulation was compared with the width of the single scanning track, and they were in good agreement. Finally, by adjusting the test strategy, it was found that the surface roughness could reach the lowest (0.88 ± 0.06 μm) only when the two structures coexisted. • High power polishing produces solidification induced surface structure with large roughness. • Low power polishing results in surface ripples with low roughness. • High power polishing is SOM mechanism, and tangential thermocapillary force is dominant. • Low power polishing is SSM mechanism, and normal capillary force predominates. • The simulation values agree well with experimental values, and the errors are all within 10 %. [ABSTRACT FROM AUTHOR]

The probability of martensitic transformation in stable 316L austenitic steel obtained using a 3D laser printer is investigated. Compressive deformation of the studied samples was carried out at room temperature at a high rate (2 × 10–2 sec–1). The features of the martensitic transition and the conditions for formation of an intermediate phase of epsilon-martensite are considered. [ABSTRACT FROM AUTHOR]

A portable sweat urea sensing system is a promising solution to satisfy the booming requirement of kidney function tele‐monitoring. However, the complicated manufacturing route and the cumbersome electrochemical testing system still need to be improved to develop the urea point‐of‐care testing (POCT) and tele‐monitoring devices. Here, a universal technical route based on a high‐throughput automatic laser printing strategy for fabricating the portable integrated urea monitoring system is proposed. This integrated system includes a high‐performance laser‐printed urea sensing electrode, a planar three‐electrode system, and a self‐developed wireless mini‐electrochemical workstation. A precursor donor layer is activated by laser scribing and in situ transferred into functional nanoparticles for the drop‐on‐demand printing of the urea sensing electrode. The obtained electrodes show high sensitivity, low detection limit, fast response time, high selectivity, good average recovery, and long‐term stability for urea sensing. Additionally, a laser‐induced graphene circuit‐based miniature planar three‐electrode system and a wireless mini‐electrochemical workstation are designed for sensing data collection and transmitting, achieving real‐time urea POCT and tele‐monitoring. This scalable method provides a universal solution for high‐throughput and ultra‐fast fabrication of urea‐sensing electrodes. The portable integrated urea monitoring system is a competitive option to achieve cost‐effective POCT and tele‐monitoring for kidney function. [ABSTRACT FROM AUTHOR]

The established approach to materials design for additive manufacturing (AM) consists of attempting to reproduce the uniform structures and properties of conventionally processed materials. While this certainly helped facilitate material certification and the rapid introduction of AM technologies in several industries, the opportunity to exploit unique features of specific AM processes to generate spatially varying microstructures–and hence novel materials, remains largely untapped. This work presents a method for manufacturing materials through laser powder bed fusion (LPBF), in which control over the spatial variation in phase composition and mechanical properties is achieved. This technique is demonstrated using 17‐4 precipitation‐hardened stainless steel (17‐4PH), by controlling spatial modulation of energy densities during printing. This results in local control of ferrite/martensite volume fractions, allowing the fabrication of metal/metal architected composites with hard/brittle regions interspersed with soft/tough regions. Local variations of ~20% in tensile strength and ~150% in elongation are achieved, with a spatial resolution of ~100 microns. The approach is general and robust, fully compatible with commercially available LPBF equipment, and applicable to virtually any multi‐phase alloy system. This work shifts the paradigm from attempting to print components with uniform properties to manufacturing alloys with controlled spatial property gradients. [ABSTRACT FROM AUTHOR]

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Parry Romberg syndrome also known as progressive hemifacial atrophy is an uncommon degenerative condition, characterized by unilateral, slow, and progressive atrophy of face. Patient presents with loss of facial symmetry and neurological manifestations. After the degenerative process settles, reconstructive surgeries are performed to address facial asymmetry. For accurate assessment of volume deficit, laser scanning and three- dimensional printing can be used which offers the advantage of precise surgical planning and good aesthetic outcome. We present a case of soft tissue reconstruction in Parry Romberg syndrome with anterolateral thigh flap with use of three- dimensional laser scanning. [ABSTRACT FROM AUTHOR]

Multiple protocols have been reported to fabricate paper-based analytical devices (PADs). However, some of these techniques must be revised because of the instrumentation required. This paper describes a versatile and globally affordable method to fabricate PADs using office paper as a substrate and a laser printing technique to define hydrophobic barriers on paper surfaces. To demonstrate the feasibility of the alternatives proposed in this study, the fabrication of devices for three types of detection commonly associated with using PADs was demonstrated: colorimetric detection, electrochemical detection, and mass spectrometry associated with a paper-spray ionization (PSI-MS) technique. Besides that, an evaluation of the type of paper used and chemical modifications required on the substrate surface are also presented in this report. Overall, the developed protocol was suitable for using office paper as a substrate, and the laser printing technique as an efficient fabrication method when using this substrate is accessible at a resource-limited point-of-need. Target analytes were used as a proof of concept for these detection techniques. Colorimetric detection was carried out for acetaminophen, iron, nitrate, and nitrite with limits of detection of 0.04 μg, 4.5 mg mL−1, 2.7 μmol L−1, and 6.8 μmol L−1, respectively. A limit of detection of 0.048 fg mL−1 was obtained for the electrochemical analysis of prostate-specific antigen. Colorimetric and electrochemical devices revealed satisfactory performance when office paper with a grammage of 90 g m−2 was employed. Methyldopa analysis was also carried out using PSI-MS, which showed a good response in the same paper weight and behavior compared to chromatographic paper. [ABSTRACT FROM AUTHOR]

Counterfeiting has become a serious global problem, causing worldwide losses and disrupting the normal order of society. Physical unclonable functions are promising hardware-based cryptographic primitives, especially those generated by chemical processes showing a massive challenge-response pair space. However, current chemical-based physical unclonable function devices typically require complex fabrication processes or sophisticated characterization methods with only binary (bit) keys, limiting their practical applications and security properties. Here, we report a flexible laser printing method to synthesize unclonable electronics with high randomness, uniqueness, and repeatability. Hexadecimal resistive keys and binary optical keys can be obtained by the challenge with an ohmmeter and an optical microscope. These readout methods not only make the identification process available to general end users without professional expertise, but also guarantee device complexity and data capacity. An adopted open-source deep learning model guarantees precise identification with high reliability. The electrodes and connection wires are directly printed during laser writing, which allows electronics with different structures to be realized through free design. Meanwhile, the electronics exhibit excellent mechanical and thermal stability. The high physical unclonable function performance and the widely accessible readout methods, together with the flexibility and stability, make this synthesis strategy extremely attractive for practical applications. The authors introduce a flexible laser printing method for synthesizing integrated optical and electric Physical Unclonable Functions (PUFs). The PUF devices can be read out by simple household equipment and show high uniqueness and stability. [ABSTRACT FROM AUTHOR]

The results of studies of a wavefront sensor based on the Talbot effect, in which a periodic grating made by laser printing is used, are presented. The optical characteristics of periodic gratings printed on polymer films exposed to a continuous radiation density of up to 0.9 W/cm2 have been studied. The possibility of creating efficient configurable wavefront sensors for lasers in the visible and mid-IR spectral ranges is demonstrated. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) involves creating prototypes by depositing and solidifying material by the placement of material in X, Y, and Z axes in a 3D space. The emergence of AM using elastomers has allowed the production of complex and customised parts with intricate geometries and modified properties as per specific needs of engineers cum designers. For successful 3D printing (3DP), it is crucial to use a material that is suitable for the specific application and printing process. Elastomers are unique polymers that are resilient, flexible and capable of deforming under stress. Fused deposition modelling, stereolithography and selective laser sintering printing are the most common 3DP techniques for elastomers. The use of elastomers in AM is limited due to technological, material and processing constraints. Despite challenges, elastomers have great potential in AM and can be applied in various industries namely automotive, aerospace, healthcare and consumer goods. However, there is a growing interest in expanding the range of elastomers that can be 3D printed. Researchers are experimenting with different approaches to enhance the printability of elastomers such as modifying material composition, material design, optimising printing parameters, control of chemical composition and 3DP techniques. Recent advancements in the structure, properties and printing techniques of elastomers show wide scope for improving their printability. Several elastomeric materials that can be 3D printed include thermoplastic elastomer, thermoplastic polyurethane, liquid silicone rubber, etc. This review paper aims at providing an overview of the current state of AM of elastomers, including the challenges and limitations. It discusses recent advancements and suggests ways to enhance the printability of elastomers in near future, which can help researchers and industry professionals to explore new and unique AM applications. [ABSTRACT FROM AUTHOR]

Conventional substrates for optoelectronic systems include inorganic or organic carrier materials; however, these systems are typically subjected to environmentally harmful multistep processes to prepare printed circuit boards. To mitigate these issues, the present article reports a polyether ether ketone (PEEK)‐based composite densely filled with copper microparticles, prepared using a simple, cost‐effective, and sustainable synthesis method. The material exhibits high thermal conductivity but is electrically nonconductive prior to undergoing laser treatment. To prevent the composite from exhibiting electrical conductivity, the copper particles are coated with a thin silica layer through a sol–gel reaction. The thermal stability of PEEK and the Cu–PEEK composites with Cu contents of up to 70 vol%, which are prepared via heat melding, is investigated by thermogravimetric analysis, differential scanning calorimetry, and Fourier‐transform infrared spectroscopy to clarify the manner in which copper affects the chemical structure of the polymer. The developed composite exhibits a significantly higher thermal conductivity than that of the unfilled PEEK polymer. This paper also describes the effects of laser treatment on the surface morphology. Overall, this study suggests that conductive tracks with low electrical resistance can be created on electrically insulating substrates with high thermal conductivity. [ABSTRACT FROM AUTHOR]

Selective laser printing offers distinct advantages for fabricating large-scale and complex-shaped SiC ceramic components. However, the high porosity and low strength exhibited by SiC green bodies manufactured by selective laser printing necessitate an efficient heat treatment method to improve density and strength. This study presents an efficient technique for preparing SiC ceramics using selective laser printing coupled with precursor impregnation and pyrolysis (PIP) and liquid phase sintering (LPS). To enhance the density of the green body, a particle gradation technique was employed. Subsequently, a selective laser printing-powder, comprising SiC, Al 2 O 3 , Y 2 O 3 , and phenolic resin, was utilized to obtain a green body with a tailored microstructure. Following selective laser printing, SiC ceramics with flexural strength of 150 MPa and relative density of 98.2 % were produced by precursor impregnation and pyrolysis, followed by pressureless sintering. The outcomes of this study demonstrate a viable strategy for fabricating high-performance SiC ceramics via selective laser printing. [ABSTRACT FROM AUTHOR]

The single-pass one-step method for printing conductive silver tracks on a glass surface, using the laser-induced forward transfer (LIFT) technique, was proposed, providing a unique opportunity for high-throughput printing of surface micro- and nanostructures with high electrical conductivity and positioning accuracy. This method was developed via our multi-parametric research, resulting in the selection of the optimal material, laser irradiation, and transfer conditions. Optical, scanning and transmission electron, and atomic force microscopy methods, as well as X-ray diffraction, were used to characterize the surface structure and phase state of the printed structures, while energy-dispersive X-ray and X-ray photoelectron microscopy were employed for their chemical microanalysis. Depending on the laser irradiation parameters, the specific electrical conductivity of the printed tracks varied from 0.18 to 83 kS/cm, approaching that of donor magnetron-sputtered films. This single-pass one-step method significantly facilitates fast, large-scale, on-demand local laser printing of metallic (sub)microcomponents of microelectronic devices. [ABSTRACT FROM AUTHOR]

Laser powder bed fusion (LPBF) additive manufacturing, as a novel technique provides broad benefits in thermoelectric materials synthesis, such as enhanced printing speed, reduced waste materials, and customized dimension design. The high energy density of laser could potentially balance the synthesis rate and thermoelectric figure-of-merit zT , but the correlations between laser energy and material performance are still vague. Herein, Bi 0.5 Sb 1.5 Te 3 bulks are directly synthesized by LPBF with a recorded synthesis rate of 254 g h−1. The maximum zT , without any post-processing, reaches 1.1 at 75 °C. Induced nanoscale pores by high laser energy printing, obtain a comparable diameter to phonon mean free path, leading to reduced lattice thermal conductivity and enhanced TE performance. We found that input laser energy critically affected thermoelectric performance and concluded the correlation between volumetric energy density E V and power factor PF , PF = 9.05 E V 2 – 30.01 E V + 48.84. It potentially predicts thermoelectric performance with inputted laser energy density. [ABSTRACT FROM AUTHOR]

The flow field structure of the bipolar plates is a key factor in determining the heat and mass transfer performance of proton exchange membrane fuel cells (PEMFC). To improve its performance and obtain an optimized design and fabrication method, this paper proposes a novel baffled flow field bipolar plate and successfully realizes its preparation using 3D printing technology. A PEMFC computational fluid dynamics model was established for numerical simulation, and polarization tests were also performed to verify the simulation results. The results show that the incorporation of 30°, 60°, and 90° sub-baffles helped to increase the maximum power density of the PEMFC by 3.5%, 8.4%, and 14.7%, respectively, compared to no sub-baffles. The oxygen mass transfer efficiency of the flow field with a 90° sub-baffle increased by 9.4% and 22.1% compared to the 60° and 30° sub-baffles, respectively. However, the increase in inclination angle also causes more water and heat in the flow channel to enter the membrane electrode, which hinders the further improvement of PEMFC performance. This study will provide new ideas and solutions for the flow field structure design and preparation of bipolar plates. [Display omitted] • A novel flow field structure with main and sub-baffle was designed. • Forming of metal bipolar plates with complex flow field structure by 3D printing. • The mass and heat transfer characteristics in different flow field structures were studied. • Oxygen transfer efficiency increases with increasing inclination of the sub-baffle. [ABSTRACT FROM AUTHOR]

Additively manufactured cutting tools have thus far proven unsuccessful in machining difficult-to-cut materials like titanium. To the knowledge of the authors, this paper demonstrates, for the first time, the form turning of Ti6Al4V with WC-Co tools printed using laser powder bed fusion (LPBF), without any material-related post-processing. Following an investigation into LPBF parameters to optimize WC-Co properties, numerical modelling was utilized to design and analyse said tools, which were then printed, finish-ground, and tested. This advance was facilitated by the enabling capabilities of LPBF, which elevated tool performance by incorporating features that are critical to machining titanium, such as cooling fins and streamlined internal coolant channels. [ABSTRACT FROM AUTHOR]