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2 pages, 161 KiB

Open AccessEditorial

Special Issue on Laser Micro/Nano Machining Technology

by Jianlei Cui

Appl. Sci. 2022, 12(24), 13013; https://doi.org/10.3390/app122413013 - 19 Dec 2022

Viewed by 1253

Abstract

Through the interaction between lasers and materials, laser micro/nano machining technology changes the materials’ physical state and properties [...] Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

Research

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17 pages, 8004 KiB

Open AccessArticle

Numerical and Experimental Research on the Laser-Water Jet Scribing of Silicon

by Yuan Li, Ye Ding, Bai Cheng, Junjie Cao and Lijun Yang

Appl. Sci. 2022, 12(8), 4057; https://doi.org/10.3390/app12084057 - 17 Apr 2022

Cited by 6 | Viewed by 1980

Abstract

Monocrystalline silicon has shown great potential in constructing advanced devices in semiconductor, photoelectric, and photochemistry fields. The fabrication of micro-grooves with large depth-to-width ratio (DTWR) and low taper is in urgent demand as this type of groove can significantly promote the device performance. [...] Read more.

Monocrystalline silicon has shown great potential in constructing advanced devices in semiconductor, photoelectric, and photochemistry fields. The fabrication of micro-grooves with large depth-to-width ratio (DTWR) and low taper is in urgent demand as this type of groove can significantly promote the device performance. The grooves with such characterizations can hardly be achieved by conventional machining techniques owing to the high hardness and brittleness of silicon. Laser waterjet (LWJ) machining is a promising solution, which is capable of ablating materials with less or no heat defects, well machining precision, and consistency. Therefore, this paper firstly established a theoretical model describing the interaction between silicon and LWJ. Through the numerical simulation, the evolution of temperature and stress distribution at the machining region was analyzed. Variation experiments were carried out correspondingly. On these bases, scribing experiments were put forward aimed at discovering the influence of machining parameters on groove morphology. Optimized scribing strategy which is capable of realizing the construction of a micro-groove with DTWR of 19.03 and taper of 0.013 was obtained. The results contributed to the understanding of LWJ processing of silicon on a small scale as well as broadening the application prospects of LWJ for treating other semiconductor devices. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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21 pages, 7290 KiB

Open AccessArticle

Study on Model and Experimental of Laser Scribing Parameter of Maskant in Chemical Milling for Aerospace Applications

by Jian Wang, Qiang Liu, Pengpeng Sun, Zhiwei Ning and Liuquan Wang

Appl. Sci. 2022, 12(6), 2914; https://doi.org/10.3390/app12062914 - 12 Mar 2022

Cited by 6 | Viewed by 2396

Abstract

In order to solve the problems of multiple process parameters, difficult control and high process requirements in laser first/second scribing of aerospace chemical milling thin-wall parts, a laser scribing depth model based on thermal energy balance was established, and the relationship between laser [...] Read more.

In order to solve the problems of multiple process parameters, difficult control and high process requirements in laser first/second scribing of aerospace chemical milling thin-wall parts, a laser scribing depth model based on thermal energy balance was established, and the relationship between laser power and speed was established with scribing depth as a target. Using AC850 laser scribing maskant as coating material, the effects of laser power, scribing speed, laser frequency, forward angle and side slope angle on the scribing depth were studied by single factor experiment. Experimental results show that the theoretical model is in good agreement with experimental data. The laser scribing depth is positively proportional to the laser power and inversely proportional to the laser speed and has little relationship with the laser frequency. The predicted accuracy of the mathematical equations regarding the laser power density and scribing depth, calculated by the laser power, speed and scribing depths experimental data, are 88.53% and 90.79%. The laser scribing depth at a forward angle of 6° and a side slope angle of 7° is deeper compared with the vertical incident scribing depth, and the angle is also the recommended angle of laser scribing. Based on the simplified regression model, the laser scribing depth model can be directly used in the laser NC system to realize the adaptive adjustment and accurate control of laser energy according to the actual laser speed. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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20 pages, 5530 KiB

Open AccessArticle

Design and Optimization of Laser Processing Control System and Process Parameters for Micro Crystal Resonator Frequency Modulation

by Jian Hu, Sangdu Guo, Bao Fang, Xindong Yu, Zhiqiang Gu and Gangyan Li

Appl. Sci. 2022, 12(4), 2162; https://doi.org/10.3390/app12042162 - 18 Feb 2022

Cited by 1 | Viewed by 1558

Abstract

The adjustment of the natural frequency of a micro crystal resonator (MCR) is the key requirement in its manufacturing, which determines the actual performance of the product. Laser processing is a new method for MCR frequency modulation, and its process parameters directly affect [...] Read more.

The adjustment of the natural frequency of a micro crystal resonator (MCR) is the key requirement in its manufacturing, which determines the actual performance of the product. Laser processing is a new method for MCR frequency modulation, and its process parameters directly affect the frequency modulation effect. Aiming at the laser processing equipment for MCR frequency modulation, the structure of the laser processing control system for MCR frequency modulation is designed by analyzing the requirements of a laser processing control system. The working flow of the laser processing control system for MCR frequency modulation is studied, the motion control method of the laser processing platform for MCR frequency modulation is proposed, and the laser processing control system for MCR frequency modulation is designed. By analyzing the laser characteristics for MCR frequency modulation, an orthogonal experiment is carried out to optimize the laser processing parameters for MCR frequency modulation. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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10 pages, 4171 KiB

Open AccessArticle

Optimization of Spot Efficiency of Double-Helix Point Spread Function and Its Application in Intracellular Imaging

by Jun Yang, Hanliang Du, Zhenhao Chai, Lei Zhang, Ben Q. Li, Jianlei Cui and Xuesong Mei

Appl. Sci. 2022, 12(4), 1778; https://doi.org/10.3390/app12041778 - 9 Feb 2022

Cited by 2 | Viewed by 1543

Abstract

The nano-scale spatial positioning of nanoparticles in tumor cells can be achieved through the double-helix point spread functions (DH-PSF). Nevertheless, certain issues such as low light intensity concentration of the main lobes, the influence of the side lobes, and the aberrations of the [...] Read more.

The nano-scale spatial positioning of nanoparticles in tumor cells can be achieved through the double-helix point spread functions (DH-PSF). Nevertheless, certain issues such as low light intensity concentration of the main lobes, the influence of the side lobes, and the aberrations of the imaging system result in poor image quality and reduce the positioning accuracy of the fluorescent nanoparticles. In this paper, an iterative optimization algorithm that combines Laguerre–Gaussian modes and Zernike polynomials is proposed. The double-helix point spread function, constructed by the linear superposition of the Laguerre–Gaussian mode and Zernike polynomials, is used to express aberrations in the imaging system. The simulation results indicated that the light intensity concentration of the main lobes is increased by 45.51% upon the use of the optimization process. Based on the simulation results, the phase modulation plate was designed and processed while a 4f positioning imaging system was built. Human osteosarcoma cells, labeled by CdTe/CdS/ZnS quantum dots, were used as samples, and the position imaging experiment was carried out. The image information entropy was used as the clarity evaluation index. The experimental results showed that the image information entropy of the DH-PSF position imaging was reduced from 4.22 before optimization to 2.65 after optimization, and the image clarity was significantly improved. This result verified the effectiveness of the optimization method that was proposed in this work. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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14 pages, 5652 KiB

Open AccessArticle

Error Model and Frequency Modulation Characteristics Analysis of Laser Processing Platform for Micro Crystal Resonator

by Jian Hu, Zhihang Li, Yanlin Wu, Xindong Yu and Gangyan Li

Appl. Sci. 2022, 12(3), 1340; https://doi.org/10.3390/app12031340 - 27 Jan 2022

Cited by 1 | Viewed by 1801

Abstract

Laser processing platform for micro crystal resonator (MCR) frequency modulation is an important piece of equipment to apply laser etching technology to the MCR frequency modulation process. The positioning accuracy of the laser processing platform has an important influence on frequency modulation characteristics. [...] Read more.

Laser processing platform for micro crystal resonator (MCR) frequency modulation is an important piece of equipment to apply laser etching technology to the MCR frequency modulation process. The positioning accuracy of the laser processing platform has an important influence on frequency modulation characteristics. In order to improve the precision and efficiency of the laser processing platform for MCR frequency modulation, the error model of the laser processing platform for MCR frequency modulation is established based on the multi-body system theory. According to the Monte Carlo simulation method, the influence of laser processing platform error for MCR on frequency modulation characteristics is analyzed. Considering the requirements of the MCR frequency modulation process, the laser processing platform for MCR frequency modulation is built, and the frequency deviation and frequency modulation performance are verified to meet the engineering requirements. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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17 pages, 9209 KiB

Open AccessArticle

Theoretical and Experimental Investigation on SiC/SiC Ceramic Matrix Composites Machining with Laser Water Jet

by Bai Cheng, Ye Ding, Yuan Li and Lijun Yang

Appl. Sci. 2022, 12(3), 1214; https://doi.org/10.3390/app12031214 - 24 Jan 2022

Cited by 6 | Viewed by 2790

Abstract

SiC/SiC ceramic matrix composites (CMCs) are widely applied in the aerospace and nuclear industries due to their excellent material nature (strength, hardness, and irradiation tolerance) at high-temperature loads. However, high-quality machining cannot be easily realized because of the anisotropic material structure and its [...] Read more.

SiC/SiC ceramic matrix composites (CMCs) are widely applied in the aerospace and nuclear industries due to their excellent material nature (strength, hardness, and irradiation tolerance) at high-temperature loads. However, high-quality machining cannot be easily realized because of the anisotropic material structure and its properties. In this study, a laser water jet (LWJ) was adopted for CMCs machining. Firstly, the finite element model (FEM) was established describing a representative three-dimensional microstructure including weft yarn, warp yarn, SiC base, and the pyrolytic carbon (PyC) fiber coating. The temperature distribution, as well as its evolution rule on substrate surface under LWJ machining, was analyzed. Moreover, a single-dot ablation test was carried out to verify the accuracy of the numerical simulation model. Secondly, the variation in maximum temperatures under different laser pulse energy was obtained by means of FEM. Nonetheless, a non-negligible deviation emerged in the ablation depth of the numerical calculation and experimental results. Although the simulation results were obviously superior to the experimental results, their proportions of different machining parameters reached an agreement. This phenomenon can be explained by the processing characteristics of LWJ. Finally, single-row and multi-row scribing experiments for CMCs with 3 mm thickness were developed to clarify the processing capacity of LWJ. The experimental results indicated that single-tow scribing has a limiting value at a groove depth of 2461 μm, while complete cutting off can only be realized by multi-row scribing of LWJ. In addition, the cross-section of CMCs treated by LWJ presented a surface morphology without a recast layer, pulling out of SiC fibers, and delamination. The theoretical and experimental results can offer primary technical support for the high-quality machining of CMCs. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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10 pages, 5520 KiB

Open AccessArticle

Improving Adhesive Bonding of Al Alloy by Laser-Induced Micro–Nano Structures

by Guang Li, Mingwei Lei, Chen Liang, Kai Li, Benhai Li, Xiaohua Wang, Junlong Wang and Zhipeng Wei

Appl. Sci. 2022, 12(3), 1199; https://doi.org/10.3390/app12031199 - 24 Jan 2022

Cited by 9 | Viewed by 2601

Abstract

In this paper, laser surface treatment of Al alloy was studied by comparison of sandblasting and laser ablation. The effects of laser spot distribution on surface roughness, contact angle, chemical composition and shear strength of Al alloy were analyzed. The experimental results showed [...] Read more.

In this paper, laser surface treatment of Al alloy was studied by comparison of sandblasting and laser ablation. The effects of laser spot distribution on surface roughness, contact angle, chemical composition and shear strength of Al alloy were analyzed. The experimental results showed that the bonding performance of Al alloy are promoted by controlling the laser spot spacing. When laser spot spacing was smaller than the size of the laser spot, micro–nano composite structures were induced by multiple laser pulses, which would improve shear strength by increasing the contact area between Al alloy and adhesive. Using laser surface treatment, the adhesion properties on Al alloy can be promoted. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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8 pages, 3007 KiB

Open AccessArticle

The Realization of ZnO Nanowires Interconnection through Femtosecond Laser Irradiation of Ag Nanoparticles Solder

by Yanchao Guan, Genwang Wang, Shouxin Zhao, Lianfu Wang, Ye Ding and Lijun Yang

Appl. Sci. 2022, 12(3), 1004; https://doi.org/10.3390/app12031004 - 19 Jan 2022

Cited by 3 | Viewed by 1378

Abstract

Nanowire interconnection is the basis for the construction and integration of micro-nano functional devices. But so far, it is still difficult to achieve a reliable interconnection of metal oxide nanowires. This letter proposes an approach for soldering ZnO nanowires through femtosecond laser irradiation [...] Read more.

Nanowire interconnection is the basis for the construction and integration of micro-nano functional devices. But so far, it is still difficult to achieve a reliable interconnection of metal oxide nanowires. This letter proposes an approach for soldering ZnO nanowires through femtosecond laser irradiation of Ag nanoparticles solder. In this paper, the effect of femtosecond laser fluence and irradiation time on the morphology of Ag solders and the interconnection state of ZnO nanowires are studied, respectively. The I-V electrical characterization of nanowire interconnection before and after soldering is completed. The results demonstrate that ZnO nanowires achieve better interconnection. The UV light response of the ZnO-Ag-ZnO interconnection structure after soldering is investigated. The approach confirms the effectiveness of a femtosecond irradiated metal nanoparticles solder to achieve metal oxide interconnection, offering the prospect of more metal oxide nanowires interconnection and device development. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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12 pages, 4074 KiB

Open AccessArticle

Simulation of Optical Nano-Manipulation with Metallic Single and Dual Probe Irradiated by Polarized Near-Field Laser

by Genwang Wang, Ye Ding, Haotian Long, Yanchao Guan, Xiwen Lu, Yang Wang and Lijun Yang

Appl. Sci. 2022, 12(2), 815; https://doi.org/10.3390/app12020815 - 13 Jan 2022

Cited by 3 | Viewed by 1445

Abstract

Nano-manipulation technology, as a kind of “bottom-up” tool, has exhibited an excellent capacity in the field of measurement and fabrication on the nanoscale. Although variety manipulation methods based on probes and microscopes were proposed and widely used due to locating and imaging with [...] Read more.

Nano-manipulation technology, as a kind of “bottom-up” tool, has exhibited an excellent capacity in the field of measurement and fabrication on the nanoscale. Although variety manipulation methods based on probes and microscopes were proposed and widely used due to locating and imaging with high resolution, the development of non-contacted schemes for these methods is still indispensable to operate small objects without damage. However, optical manipulation, especially near-field trapping, is a perfect candidate for establishing brilliant manipulation systems. This paper reports about simulations on the electric and force fields at the tips of metallic probes irradiated by polarized laser outputted coming from a scanning near-field optical microscope probe. Distributions of electric and force field at the tip of a probe have proven that the polarized laser can induce nanoscale evanescent fields with high intensity, which arouse effective force to move nanoparticles. Moreover, schemes with dual probes are also presented and discussed in this paper. Simulation results indicate that different combinations of metallic probes and polarized lasers will provide diverse near-field and corresponding optical force. With the suitable direction of probes and polarization direction, the dual probe exhibits higher trapping force and wider effective wavelength range than a single probe. So, these results give more novel and promising selections for realizing optical manipulation in experiments, so that distinguished multi-functional manipulation systems can be developed. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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9 pages, 2500 KiB

Open AccessArticle

Laser Fabrication of Titanium Alloy-Based Photothermal Responsive Slippery Surface

by Jian Yi, Hao Zhou, Xingchen Han, Jiangwei Mao and Yonglai Zhang

Appl. Sci. 2022, 12(2), 608; https://doi.org/10.3390/app12020608 - 9 Jan 2022

Cited by 1 | Viewed by 1369

Abstract

In recent years, biomimetic materials inspired from natural organisms have attracted great attention due to their promising functionalities and cutting-edge applications, emerging as an important research topic. For example, how to reduce the reflectivity of the solid surface and increase the absorption of [...] Read more.

In recent years, biomimetic materials inspired from natural organisms have attracted great attention due to their promising functionalities and cutting-edge applications, emerging as an important research topic. For example, how to reduce the reflectivity of the solid surface and increase the absorption of the substrate surface is essential for developing light response smart surface. Suitable solutions to this issue can be found in natural creatures; however, it is technologically challenging. In this work, inspired from butterfly wings, we proposed a laser processing technology to prepare micro nanostructured titanium alloy surfaces with anti-reflection properties. The reflectivity is significantly suppressed, and thus, the light absorption is improved. Consequently, the anti-reflection titanium alloy surface can be further employed as a photothermal substrate for developing light-responsive slippery surface. The sliding behavior of liquid droplets on the smart slippery surface can be well controlled via light irradiation. This method facilitates the preparation of low-reflection and high-absorption metallic surfaces towards bionic applications. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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14 pages, 14093 KiB

Open AccessArticle

Study on Nanosecond Laser Ablation of 40Cr13 Die Steel Based on ANOVA and BP Neural Network

by Zhenshuo Yin, Qiang Liu, Pengpeng Sun and Jian Wang

Appl. Sci. 2021, 11(21), 10331; https://doi.org/10.3390/app112110331 - 3 Nov 2021

Cited by 6 | Viewed by 1753

Abstract

Microstructured steel 40Cr13, which is considered a hard-to-machine steel due to its high mechanical strength and hardness, has wide applications in the dies industry. This study investigates the influence of three process parameters of a 355 nm nanosecond pulse laser on the ablation [...] Read more.

Microstructured steel 40Cr13, which is considered a hard-to-machine steel due to its high mechanical strength and hardness, has wide applications in the dies industry. This study investigates the influence of three process parameters of a 355 nm nanosecond pulse laser on the ablation results of 40Cr13, based on analysis of variance (ANOVA) and back propagation (BP) neural network. The ANOVA results show that laser power has the greatest influence on the ablation depth, width, and material removal rate (MRR), with influence levels of 52.5%, 60.9%, and 70.4%, respectively. The scan speed affects the ablation depth and width to a certain extent, and the influence of the pulse frequency on the ablation depth and MRR is non-negligible. BP neural network models with 3-8-3, 3-10-3, and 3-12-3 structures were applied to predict the ablation results. The results show that the prediction accuracy is relatively high for the ablation width and MRR, with average prediction accuracies of 96.0% and 93.5%. The 3-8-3 network model has the highest prediction accuracy for the ablation width, and the 3-10-3 network model has the highest prediction accuracy for the ablation depth and MRR. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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10 pages, 1331 KiB

Open AccessArticle

Control of a Digital Galvanometer Scanner Using a Discrete-Time Sliding-Mode Variable-Structure Controller Based on a Decoupled Disturbance Compensator

by Guangsheng Chen and Yunlong Wang

Appl. Sci. 2021, 11(21), 9788; https://doi.org/10.3390/app11219788 - 20 Oct 2021

Cited by 2 | Viewed by 2034

Abstract

Laser processing plays an important role in industrial manufacturing, in which a galvanometer scanner (GS) functions as the core component of the laser processing equipment. With the development of the digital system, the GS based on the digital system finds a broader range [...] Read more.

Laser processing plays an important role in industrial manufacturing, in which a galvanometer scanner (GS) functions as the core component of the laser processing equipment. With the development of the digital system, the GS based on the digital system finds a broader range of potential application. In order to address the slow step-responses of a GS with disturbance and parameter perturbation, the mathematical model of the motor of the GS is derived and a discrete-time sliding-mode variable-structure controller (DSVC) based on a decoupled disturbance compensator (DDC) (DSVC+DDC) is designed. The step-response performance of a GS is the key factor affecting the quality evaluation of laser processing. Experiments are conducted on the step responses of the motor of the GS on a digital experimental platform. The experiment results show that when guaranteeing a steady-state error within 20 urad and an overshoot of less than 5%, the rise time for step-responses in 1% and 10% of the whole stroke is 1 and 2 ms, decreasing by 23% and 58% compared with the reference performance index, which indicates the effectiveness of the proposed method. The proposed approach can not only compensate for the external disturbance online and improve the step-response speed of the GS, but also relax the traditionally assumed limit of the upper bound of external disturbance to the limit of the change rate of external disturbance, which reduces the difficulty of a practical application. This method has great significance for further applications in high precision machining. Full article

(This article belongs to the Special Issue Laser Micro/Nano Machining Technology)

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