Search Results (119)

Laser engraving may be used in a variety of industries, from medicine to defense, and it has many uses that require high-quality precision production. However, in practice, operators have to adjust the laser settings manually, which can result in wasted material and poor color quality and even decrease productivity. Current optimization approaches mostly concentrate on single objectives, making it impossible to co-optimize engraving quality and production efficiency simultaneously. In this paper, an approach based on a multi-objective genetic algorithm, a combination of NSGA-II, SPEA2, and MOEA/D, is proposed to automatically establish the relationship between CMYK color attributes, which are extracted from images of engravings, and laser parameters (power, speed, and frequency). Anodized aluminum 6061 was laser-processed using an SPI 30W fiber laser. While the proposed framework is general, the experimental validation in this study was specifically constrained to this material. The results also indicate that MOEA/D converges in a short time and becomes relatively stable after 20 generations. NSGA-II results in solutions that are more diverse, and SPEA2 offers a good trade-off between the speed of convergence and solution size. This approach resulted in optimization in terms of both a decrease in material used and color matching between manual operations, with the average CMYK improvement being up to 28%. Our results indicate that multi-objective evolutionary optimization is feasible for the optimization of efficiency and quality in laser cutting. Full article

Hydrogels with spatially programmable mechanical properties hold great potential for use in biomedical applications. Inspired by the architecture of the cytoskeleton, we present a strategy for constructing tensegrity-structured hydrogels (TS-Gels) through enzyme-triggered crystal growth to enable precise mechanospatial manipulation. Specifically, alkaline phosphatase (ALP) was covalently anchored to a polyacrylamide (PAAm) hydrogel matrix to catalyze the in situ dephosphorylation of phosphotyrosine precursors, leading to the formation of rigid tyrosine crystals. These crystals functioned as compressive sticks, establishing tensegrity structures within the hydrogel network. By tuning the crystallization kinetics, both the structural morphology and mechanical reinforcement could be precisely controlled. The resulting TS-Gels exhibited significantly enhanced local tensile strength and stiffness, allowing for spatial–mechanical patterning via photo-initiated printing, mold-assisted shaping, and laser engraving. Furthermore, the unique mechanospatial tunability of TS-Gels was demonstrated in tribological surface engineering, underscoring their potential for use in tissue engineering and responsive biomaterials. Full article

Flexible sensors have emerged as essential components in next-generation technologies such as wearable electronics, smart healthcare, soft robotics, and human–machine interfaces, owing to their outstanding mechanical flexibility and multifunctional sensing capabilities. Despite significant advancements, challenges such as the trade-off between sensitivity and detection range, and poor signal stability under cyclic deformation remain unresolved. To overcome the aforementioned limitations, this work introduces a high-performance soft sensor featuring a dual-layered electrode system, comprising silver nanoparticles (AgNPs) and a composite of multi-walled carbon nanotubes (MWCNTs) with carbon black (CB), coupled with a laser-engraved crack-gradient microstructure. This structural strategy facilitates progressive crack formation under applied strain, thereby achieving enhanced sensitivity (1.56 kPa⁻¹), broad operational bandwidth (50–600 Hz), fine frequency resolution (0.5 Hz), and a rapid signal response. The synergistic structure also improves signal repeatability, durability, and noise immunity. The sensor demonstrates strong applicability in health monitoring, motion tracking, and intelligent interfaces, offering a promising pathway for reliable, multifunctional sensing in wearable health monitoring, motion tracking, and soft robotic systems. Full article

Mycelium-bonded composites (MBCs), or myco-composites, represent a novel engineered material that combines natural lignocellulosic substrates with a fungal matrix. As a sustainable alternative to plastics, MBCs are gaining increasing interest; however, their large-scale industrial adoption remains limited, partly due to low social acceptance resulting from their unattractive appearance. Laser engraving provides a promising method for fabricating intricate patterns and functional surfaces on MBCs, minimizing tool wear, material loss, and environmental impact, while enhancing esthetic and engineering properties. This study investigates the influence of CO₂ laser parameters on the material removal rate during the engraving of myco-composites, focusing on the effects of variable laser power, beam defocus, and head feed rate on engraving outcomes. The results demonstrate that laser power and beam focus significantly impact material removal in mycelium-bonded composites. Specifically, increasing the laser power results in greater material removal, which is more pronounced when the beam is focused due to higher energy density. In contrast, a beam defocused by 1 mm produces less intense material removal. These findings highlight the critical role of beam focus—surpassing the influence of power alone—in determining engraving quality, particularly on irregular or uneven surfaces. Moreover, reducing the laser head feed rate at a constant power level increases the material removal rate linearly; however, it also results in excessive charring and localized overheating, revealing the low thermal tolerance of myco-composites. These insights are essential for optimizing laser processing techniques to fully realize the potential of mycelium-bonded composites as sustainable engineering materials, simultaneously maintaining their appearance and functional properties. Full article

Poly(dimethylsiloxane) (PDMS) is a predominantly utilized negative triboelectric material in triboelectric nanogenerators (TENGs). Its surface topography and synergistic interaction with positive triboelectric materials significantly impact the performance of TENGs. Here, we propose a simple and cost-effective approach to promote the performance of a dual-surface-modified TENG using microwave-structured aluminum (MW-Al) together with microcone-structured polydimethylsiloxane (MC-PDMS). Laser-engraved molds were employed to cold-imprint the MC-Al and pattern the MC-PDMS. Subsequently, the impact of the heights of microcones generated under varying laser powers on the performance of TENGs was explored. The output performance of the MW-MC-TENG significantly increased with microcone heights from 0 to 228 μm. The MW-MC228-TENG, with the highest cone heights, can produce the best open-circuit voltage of 157 V and a short-circuit current of 78.5 µA, resulting in a more than 37% improvement compared to the TENG using flat polymer. Furthermore, the MW-MC228-TENG showed a power density of 16.4 W/m², sufficient to power 198 LEDs. Finally, the proposed TENG was integrated as a sensor into an impact warning system. We triggered a voice–visual warning when the TENG impacted, proving its potential for intelligent home safety monitoring. Full article

Laser engraving is a widely used technique for bamboo applications. However, the literature lacks a recommended standard roughness parameter or a numerical comparison between samples for a quantitative assessment of surface texture post-engraving. In this research, we systematically evaluated well-known 2D roughness parameters typically used for metal parts and measured them for laser bamboo engraving under various laser conditions. We utilized a pulsed laser with a 450 nm wavelength and 5.5 W power to engrave bamboo specimens, examining the surface roughness at different speed and power combinations. We utilized all available parameters with calibrated equipment to compare the results and identify the most relevant ones for characterizing the final texture with sufficient resolution for bamboo specimens. Unlike existing studies, which were limited by testing materials and laser conditions, we propose only two 2D measurement parameters that can be evaluated and compared across different materials and engraving lasers, not just under specific conditions. These selected combinations of R and P parameters can determine the quality of the engraved surface with a single measurement. In this paper the Rz parameter is proposed as the quantitative parameter to characterize the engraving. Full article

A straightforward and economical engraving diode laser with a 455 $\pm$$5$ nm visible wavelength was employed for the first time in a pulsed laser fragmentation in liquid (PLFL) technique coupled simultaneously with a chemical reduction method to synthesize silver nanoparticles (AgNPs) in an Origanum majorana extract liquid, as a natural reduction agent. The chemical reduction correlated with the PLFL method to control the NP size by examining the effect of irradiation times. The AgNPs were characterized by X-Ray diffraction (XRD), UV–vis spectrophotometry, dynamic light scattering (DLS), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The lattice diffraction Bragg’s planes (111), (200), (220), (311), and (222) were found by XRD. The AgNPs had a surface plasmon resonance (SPR) peak at around 432–409 nm. The position of this SPR peak moves toward shorter wavelengths, by around 23 nm, with increased laser irradiation. When exposure times were increased, a drop in Ag NP size was revealed, from 22 nm when only a chemical reduction approach was used to 12 nm when the PLFL technique was associated. The DLS and TEM confirmed the UV–vis results. Such consideration suggests that combining the chemical reduction and PLFL methods could enable the tuning of the Ag NP size to be tailored for specific applications. This work could open the field for synthesizing NPs and controlling their size using an easy and handy engraving laser. Full article

This study explores the effects of nanosecond short-pulsed fiber laser processing on AISI 301LN stainless steel, focusing on optimizing surface characteristics through precise parameter control. Using a Design of Experiments (DOE) approach combined with response surface methodology (RSM), the influence of laser power (30–60 W) and the number of laser passes (5–15 times) was systematically investigated. The results demonstrate that increasing the laser power and passes significantly affected the surface properties. The highest surface roughness of 16.8 µm and engraving width of 51 µm were achieved with 60 W power and 15 passes, whereas the lowest roughness of 13.8 µm and width of 35 µm were observed with 30 W power and 5 passes. Wettability measurements revealed an inverse correlation with roughness, with contact angles ranging from 86.4° for rougher surfaces to 92.4° for smoother textures. The findings demonstrate the capability of short-pulsed fiber laser processing to tailor surface properties effectively, with potential applications in manufacturing and surface engineering where controlled roughness and wettability are critical. Full article

To improve the shear strength of the 2A12 aluminum alloy adhesive-bonded joint, two kinds of surface micropatterns, parallel and cross waves, were constructed on the surface of aluminum alloy by a laser engraving machine. The shear strength of two different surface micropatterns at different laser processing distances was investigated. The results show that the surface of the aluminum alloy with a surface micropattern shows excellent hydrophilicity, which is beneficial to forming a mechanical interlock between the adhesive and aluminum alloy. The shear strength of the bonded joint decreases with the increase in laser processing distances for the parallel wavy micropattern. When the laser processing distance is 0.5 mm, the shear strength reaches a maximum of 14.04 MPa. For the cross-wave micropattern, the shear strength of the bonded joint increases first and then decreases with the increase in laser processing distances. When the laser processing distance is 0.75 mm, the shear strength reaches a maximum of 13.74 MPa. The obtained data are important for adhesive aluminum alloys with different surface micropatterns. Full article

A spiral microfluidic chip (SMC) and multi-spiral microfluidic chip (MSMC) for lipid nanoparticle (LNP) production were fabricated using a CO₂ laser engraving method, using perfluoropolyether (PFPE) and poly(ethylene glycol) diacrylate as photopolymerizable base materials. The SMC includes a spiral microchannel that enables rapid fluid mixing, thereby facilitating the production of small and uniform LNPs with a size of 72.82 ± 24.14 nm and a PDI of 0.111 ± 0.011. The MSMC integrates multiple parallel SMC structures, which enables high-throughput LNP production without compromising quality and achieves a maximum production capacity of 960 mL per hour. The LNP fabrication technology using SMC and MSMC has potential applications in the pharmaceutical field due to the ease of chip fabrication, the simplicity and cost-effectiveness of the process, and the ability to produce high-quality LNPs. Full article

The aim of the research is to investigate the impact of laser operation parameters on the LIG (laser-induced graphene) process. It focuses on evaluating the feasibility of using the induced conductive layers to create antenna circuits that are dedicated to radio-frequency identification (RFID) technology. Given the specific design of textile RFIDtex transponders, applying the LIG technique to fabricate antenna modules on a flexible substrate (e.g., Kapton) opens new possibilities for integrating RFID labels with modern materials and products. The paper analyses the efficiency of energy and data transmission in the proposed innovative UHF RFID_LIG tags. The signal strength, read range, and effectiveness are estimated in the experimental setup, providing key insights into the performance of the devices. Based on the obtained results, it can be concluded that changes in laser cutting parameters, the size of the induced graphene layer, and the method of fixing the Kapton substrate significantly affect the quality of the cutting/engraving components and the conductivity of burned paths. However, these changes do not directly affect the correct operation of the RFID_LIG transponders, owing to the fact that these structures are resistant to external impacts. Nevertheless, an increased range of data readout from the RFID_LIG tags can be achieved by using graphene paths with higher conductivity. The obtained results confirm the validity of the proposed concept and provide a foundation for further research on adapting the LIG method to automated logistics, ultimately leading to the development of more versatile and innovative solutions for identification processes. Full article

A shape-controllable laser-engraving treatment (LET) and aramid pulp (AP)-reinforced resin pre-coating (RPC) were used on a titanium (Ti) alloy surface to construct micro-/nano-aramid pulp and epoxy (MAPE) coatings for greater bonding strength with carbon fiber-reinforced polymers (CFRPs). The array pits of regular hexagon on the Ti alloy surface were engraved and vertical spaces between the array pits were created to place the AP-reinforced epoxy for stronger mechanical interlocking. The specimen treated with laser engraving (side length of 0.3 mm) and AP-reinforced RPC yielded the greatest bonding strength of 27.1 MPa, 67.4% higher than the base strength. The failure modes of the Ti-CFRPs composites changed from debonding failure at the Ti/epoxy surface to fiber-damaged failure of the laminated CFRPs panels. The shape-controllable LET and simple AP-reinforced RPC were confirmed as the most feasible and effective combined methods for use on titanium alloy surfaces for manufacturing stronger Ti-CFRPs composites, which exhibited the potential for application in other metal–matrix-bonding composite systems. Full article

Microfluidic devices are greatly affected by the materials used. The materials used in previous studies had problems in various aspects, such as processing, adsorption, and price. This study will investigate the materials needed to overcome such problems. Various microfluidic devices based on the perfluorinated compound perfluoropolyether (PFPE) were fabricated and mixed with hydrophilic and amphiphilic monomers, including poly(ethylene glycol) diacrylate, polyethylene glycol monomethacrylate, poly(ethylene glycol) methyl ether methacrylate, acrylic acid, and 2-hydroxyethyl methacrylate. A PFPE-based sheet with a repeating structure of hydrophobic and hydrophilic groups was fabricated. Thus, the hydrophilicity of highly hydrophobic PFPE was enhanced. The fluidic channel was engraved on a PFPE-based sheet using laser cutting and a fabricated microfluidic device. The channels of microfluidic devices are micro-scale (100 µm~300 µm). The lipid nanoparticles and droplets generated through the microfluidic device demonstrated uniform particles continuously. Full article

This study evaluated the influence of infrared laser radiation produced by a CO₂ laser, performing under different engraving parameters, on the colour changes and chemical composition of a beech wood surface. The results showed that the lightness clearly decreased with increasing laser power and density. At the highest laser power and the highest raster density, the ΔL* value was 51.3. The values of coordinates a* and b* moderately increased up to a raster density of 5 mm⁻¹; then, with a subsequent raster density increase, the values of these coordinates decreased again. However, the coordinate values were positive in all cases. Even the lowest laser power and raster density resulted in conspicuous discolouration or even a completely new colour compared to the original (ΔE = 10) of the beech wood surface. Further increases in the laser power and raster density resulted in progressively pronounced colour differences and a darker brown colour of the surface. The ATR-FTIR chemical analysis of the beech wood surface revealed that discolouration was mainly caused by heat-induced processes associated with the degradation of carbonyl groups (C=O) in lignin and hemicelluloses. The splitting of C=O bonds induced changes in the content of chromophores responsible for the natural wood colour and for the engraving-related discolouration. The study demonstrates that the amount of energy supplied onto the wood surface by a laser beam using diverse combinations of radiation parameters can be represented by a single variable: the total irradiation dose. The functional relation detected between this variable and the colour differences may serve as a basis for using a controlled laser beam for targeted wood surface discolouration to improve the quality of patterns transferred onto a wood surface. Knowledge of this relation will enable the targeted setting of the laser parameters during engraving so that the laser beam can be used as a tool for transferring high-quality patterns onto wood surfaces. Full article

Designing and fabricating a highly sensitive non-enzymatic glucose sensor is crucial for the early detection and management of diabetes. Meanwhile, the development of innovative electrode substrates has become a key focus for addressing the growing demand for constructing flexible sensors. Here, a simple one-step laser engraving method is applied for preparing laser-induced graphene (LIG) on polyimide (PI) film, which serves as the sensor substrate. NiCo-layered double hydroxides (NiCo-LDH) are synthesized on LIG as a precursor, utilizing the zeolitic imidazolate framework (ZIF-67), and then reacted with Ni(NO₃)₂ via solvent-thermal methods. The sensitivity of the non-enzymatic electrochemical glucose sensor is significantly improved by employing NiCo-LDH/LIG as the sensing material. The porous and interconnected structure of NiCo-LDH, derived from ZIF-67, enhances the accessibility of electrochemically active sites, while the incorporation of LIG ensures exceptional conductivity. The combination of NiCo-LDH with LIG enables efficient electron transport, leading to an increased electrochemically active surface area and enhanced catalytic efficiency. The fabricated electrode achieves a low glucose detection limit of 0.437 μM and demonstrates a high sensitivity of 1141.2 and 631.1 μA mM⁻² cm⁻² within the linear ranges of 0–770 μM and 770–1970 μM, respectively. Furthermore, the NiCo-LDH/LIG glucose sensor demonstrates superior reliability and little impact from other substances. A flexible integrated LIG-based non-enzymatic glucose sensor has been developed, demonstrating high sensitivity and suggesting a promising application for LIG-based chemical sensors. Full article