Industrial Laser Research Articles

RSM Modeling and Validation of Glass Assisted Laser Micro Drilling of Silicon Wafer

Rapid growths in the electronic industries provide opportunities for the industries to expand the using of silicon wafer in modern and advanced technologies especially Micro Electromechanical Systems (MEMS). Laser cutting is one of the most significant and important application for fabrication MEMS components. The objective of this study is to investigate the cutting capability of industrial laser, CO2 laser, in silicon wafer processing. Experiment was conducted in two conditions which is with assisted of pyrex glass and without assist of pyrex glass. In this work, silicon wafer with thickness 525 μm were cut into several rectangular sample shapes. The surface roughness produce at the cutting edge on each sample were investigated and analyzed. Analysis of Variance (ANOVA) was used to analyze the result and generated an appropriate model for the laser cutting processing. The laser parameters involved were laser power, cutting speed, and pulse frequency. Experimental results evident that, the laser cutting process with assist of glass give a better surface roughness on silicon cutting edge compared to without assist of glass.

Laser cutting machine-induced maculopathy and spontaneous recovery

The thermal effects of laser cutting machines could damage the macula. A few studies in the literature have described macular injury induced by industrial laser burns. The aim of this study was to report the clinical, visual, and optical coherence tomography findings in a gold refinery worker with laser-induced maculopathy. A 21-year-old male gold refinery worker had vision loss in his right eye after using a laser cutting machine without wearing laser eye protection gear. At the first visit (24 h later), his best-corrected visual acuity was 7/10 in the right eye and 10/10 in the left eye. The anterior segment examination was normal. In fundus examination, focal, round, and yellowish lesion was detected within the fovea. The optical coherence tomography findings were foveal outer retinal disruptions and irregularities extending from the outer plexiform layer to the retina pigment epithelium. After 4 months, the best-corrected visual acuity had improved to 1.0, and the optical coherence tomography findings had resolved.

Ex vivo digital comparison of four impression techniques using an industrial laser scanner

Introduction: The aim of the study was to compare different impression techniques used for fixed prosthodontics. Methodology: A master cast with prepared abutments was created from polymethyl-methacrylate (PMMA). A high-resolution industrial scanner was used to create a virtual reference model. Four different impressions were made, three with polyvinyl-siloxane (PVS) (n = 10 for each): one-step putty-wash (1SPW), two-step putty-wash prepared with an escape channel (2SPW-Ch), two-step putty-wash with a polyethylene spacer foil (2SPW-Fo), and one with polyether monophasic technique (MP) from the PMMA model and digitized with an industrial scanner. The stereolithographic (STL) files of the impressions (n = 40) were exported. Each file was compared to the reference using the Geomagic Verify software. Six points were assigned to enable virtual calliper measurement of tooth diameters and distances of varying sizes within the arch. Results: In the case of die diameters, the deviation from the mould ranged from 31.84 to 180.64 μm. At the stump diameter level, the MP and 1SPW techniques showed significantly more minor differences than the 2SPW-Ch, and the MP was significantly more accurate than the 2SPW-Fo. At medium distance, the deviation ranged from 42.74 to 136.47 μm. Therefore, MP was found to be significantly more accurate than 2SPW-Ch. When examining the long distance, the difference was between 162.62 and 348.85 μm. The MP and 1SPW impression techniques proved significantly more accurate than the 2SPW-Ch technique for long distances. Conclusions: With both simultaneous techniques, significantly more true results were achieved than with the two-step techniques. Keywords: Dental Impression Technique; Scanning of the Impression; Monophase; One-Step Putty-Wash; Two-Step Putty-Wash.

Ex vivo digital comparison of four impression techniques using an industrial laser scanner

Introduction The aim of the study was to compare different impression techniques used for fixed prosthodontics. Methodology A master cast with prepared abutments was created from polymethyl-methacrylate (PMMA). A high-resolution industrial scanner was used to create a virtual reference model. Four different impressions were made, three with polyvinyl-siloxane (PVS) (n = 10 for each): one-step putty-wash (1SPW), two-step putty-wash prepared with an escape channel (2SPW-Ch), two-step putty-wash with a polyethylene spacer foil (2SPW-Fo), and one with polyether monophasic technique (MP) from the PMMA model and digitized with an industrial scanner. The stereolithographic (STL) files of the impressions (n = 40) were exported. Each file was compared to the reference using the Geomagic Verify software. Six points were assigned to enable virtual calliper measurement of tooth diameters and distances of varying sizes within the arch. Results In the case of die diameters, the deviation from the mould ranged from 31.84 to 180.64 µm. At the stump diameter level, the MP and 1SPW techniques showed significantly more minor differences than the 2SPW-Ch, and the MP was significantly more accurate than the 2SPW-Fo. At medium distance, the deviation ranged from 42.74 to 136.47 µm. Therefore, MP was found to be significantly more accurate than 2SPW-Ch. When examining the long distance, the difference was between 162.62 and 348.85 µm. The MP and 1SPW impression techniques proved significantly more accurate than the 2SPW-Ch technique for long distances. Conclusions With both simultaneous techniques, significantly more true results were achieved than with the two-step techniques.

Feature extraction based on scalable hypothesis tests from photodiode data in laser welding processes

Inline monitoring technologies gain increasing importance in industrial laser welding applications. Multiple sensing technologies can be implemented for classification of welding defects. Feature extraction from sensing data is a time-consuming process due to various algorithm possibilities for the identification of relevant features. Feature extraction based on scalable hypothesis tests (FRESH) allows for feature extraction with a combination of various time series characterization methods. FRESHs feature selection promises a quick extraction of relevant features from sensing data with an automatically configured hypothesis test. In the example of classification of spatter events, we show that FRESH can be used for the extraction of relevant features with photodiode sensing data in laser welding of copper.

Smart closed-loop control of laser welding using reinforcement learning

The present work demonstrates an adaptive closed-loop control for laser welding processes. Based on feedback signals from a sensing system, the controller interacts with the laser to adapt the processing parameters to achieve or maintain the target welding quality. The controller is constructed based on a model-free reinforcement learning approach, namely Q-learning. This algorithm allows autonomous learning of the control law independently from the starting conditions as well as any prior knowledge of the process dynamics. The controller's performance is demonstrated in both a well-controlled lab environment and more unpredictable industrial situations. For the demonstration, the control system is allowed to vary the laser power, and the feedback signal is given by an industrial laser process control unit (Coherent SmartSense+) using an optical sensor. The time needed to train the control system is approximately five and twenty minutes for the well-controlled and the industrial situations, respectively.

Laser Powder Bed Fusion of an Al-Mg-Sc-Zr Alloy: Manufacturing, Peak Hardening Response and Thermal Stability at Peak Hardness

This study shows a rapid and systematic approach towards identifying full density and peak hardness for an Al-Mg-Sc-Zr alloy commonly known as Scalmalloy®. The alloy is tailored for the laser powder bed fusion process and has been shown to be printable with >99.8% relative density. The microstructure suggests Al grain refinement in melt pool boundaries, associated with formation of primary Al3(Sc,Zr) particles during solidification. Peak hardening response was identified by heat treatment tests at 573,598 and 623 K between 0 and 10 h. A peak hardness of 172 HV0.3 at 598 K for 4 h was identified. The mechanical properties were also tested with yield and ultimate strengths of 287 MPa and 364 MPa in as-printed and 468 MPa and 517 MPa in peak hardened conditions, respectively, which is consistent with the literature. Such an approach is considered apt when qualifying new materials in industrial laser powder bed fusion systems. The second part of the study discusses the thermal stability of such alloys post-peak-hardening. One set of samples was peak hardened at the conditions identified before and underwent secondary ageing at three different temperatures of 423,473 and 523 K between 0 and 120 h to understand thermal stability and benchmark against conventional Al alloys. The secondary heat treatments performed at lower temperatures revealed lower deterioration of hardness over ageing times as compared to the datasheets for conventional Al alloys and Scalmalloy®, thus suggesting that longer ageing times are needed.

Modeling optical emission from a highly multi-mode step-index fiber via ray tracing and the limitations.

Geometric optics is widely applied for diverse optical simulations. In this work, we introduce an incoherent ray model to describe the laser beam radiation emitted from a highly multi-mode step-index fiber, which is frequently applied for industrial laser material processing. First the mathematical validation and the limitation of this model are demonstrated. Then we determine the ray density and the angular spectrum according to measured intensity profiles along the caustic. Furthermore, based on the determined information, we demonstrate the simulation and measurement of the laser beam shaped by an axicon telescope. Not only the reconstruction itself, but also the simulation with free form optics present significant agreements to the measurements. The reasonable modeling of a laser source via geometric optics enables the precise determination of laser radiation and propagation properties with refractive beam shaping technologies.

Point cloud and BIM model registration based on genetic algorithm and ICP algorithm

With the rapid development of the construction industry, BIM technology, and 3D laser scanning technology are being used more and more widely, and there are many applications of combining BIM technology with 3D laser scanning technology, such as quality inspection, progress inspection, or digital preservation of ancient buildings. Therefore, this paper proposes a 3D point cloud and BIM model registration scheme based on genetic algorithm and ICP algorithm, firstly, the point cloud data is pre-processed by statistical denoising method for denoising and downsampling, and the BIM model data is converted to format data; then the coarse registration is performed by genetic algorithm, and the accurate registration is performed by ICP algorithm based on KD-tree, and finally, we experimentally verify the feasibility of the algorithm in this paper, and compared with the ICP algorithm, the registration efficiency and accuracy of the algorithm in this paper are greatly improved.

Design of optical Fabry–Perot filters for spectral combination of laser beams

Types of spectral combinations of beams of industrial lasers are considered. The optical Fabry–Perot filters are demonstrated to be an acceptable alternative to surface and volume diffraction gratings and edge dichroic filters. Known methods for designing Fabry–Perot filters for spectral multiplexing of channels in fiber-optic telecommunications are updated considering peculiarities of industrial lasers such as different emission power, transmission and suppression bandwidths of filters, and maintenance of minimum power loss. The applicability of the proposed approach is demonstrated using filters for combination of beams of ytterbium fiber lasers as an example.

A comparative investigation of different overlaps of the diode laser hardening in low-carbon steel and stainless steel

In this paper, the effect of laser overlap on the low-carbon and stainless steel are investigated. The analyzed samples are made of AISI 4130 low-Carbon steel and AISI 410 stainless steel with 50% overlap. The used laser is an industrial high-power diode laser with a continuous wave and a maximum power of 2 kW. Samples are fabricated using optimized levels for laser power, focal plane position, and laser scanning speed, and the heat-treatment process is done after that. The parameters and conditions for the laser hardening process of both samples are the same situation. Then, the microstructure analysis is done using OM and SEM. Besides, the hardness of the samples is tested in the hardening depth and width. The study shows that the hardness is improved for both samples at the overlap area, up to 762 hv for AISI 4130 and 675 hv for AISI 410. Also, in both samples the amount of ferrite phase has decreased.

Industrial Laser Welding Defect Detection and Image Defect Recognition Based on Deep Learning Model Developed

Aiming at the problem of the poor robustness of existing methods to deal with diverse industrial weld image data, we collected a series of asymmetric laser weld images in the largest laser equipment workshop in Asia, and studied these data based on an industrial image processing algorithm and deep learning algorithm. The median filter was used to remove the noises in weld images. The image enhancement technique was adopted to increase the image contrast in different areas. The deep convolutional neural network (CNN) was employed for feature extraction; the activation function and the adaptive pooling approach were improved. Transfer Learning (TL) was introduced for defect detection and image classification on the dataset. Finally, a deep learning-based model was constructed for weld defect detection and image recognition. Specific instance datasets verified the model’s performance. The results demonstrate that this model can accurately identify weld defects and eliminate the complexity of manually extracting features, reaching a recognition accuracy of 98.75%. Hence, the reliability and automation of detection and recognition are improved significantly. The research results can provide a theoretical and practical reference for the defect detection of sheet metal laser welding and the development of the industrial laser manufacturing industry.

MP18-04 LUMENIS PULSE™ MOSES™ TECHNOLOGY IMPROVES EFFICIENCY OF LASER LITHOTRIPSY FOR PATIENTS UNDERGOING MINI-PCNL

You have accessJournal of UrologyStone Disease: Surgical Therapy II (MP18)1 Sep 2021MP18-04 LUMENIS PULSE™ MOSES™ TECHNOLOGY IMPROVES EFFICIENCY OF LASER LITHOTRIPSY FOR PATIENTS UNDERGOING MINI-PCNL Meagan Dunne, Max Drescher, Joel Abbott, and Julio Davalos Meagan DunneMeagan Dunne More articles by this author , Max DrescherMax Drescher More articles by this author , Joel AbbottJoel Abbott More articles by this author , and Julio DavalosJulio Davalos More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002003.04AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The utilization of Lumenis Pulse™ 120W MOSES™ holmium laser has been associated with improved operative times for treatment of urolithiasis through retrograde ureteroscopy. We compare the utilization of MOSES Technology with an industry standard holmium laser fiber during mini and ultra-mini access percutaneous nephrolithotomy (MPCNL). METHODS: This was a retrospective case series of MPCNL, defined as PCNL with renal access diameter from 11-20F. All surgical cases were performed at a single ambulatory surgical center by one of two endourologic specialists between July 2017 and July 2020. Patients underwent laser lithotripsy and stone extraction through a MPCNL access sheath. Lithotripsy was performed using either MOSES holmium laser fiber or an industry standard holmium laser fiber (the same respective fiber was used for every case in each arm). Patient and laser records were analyzed for laser performance with a primary endpoint of treatment efficiency score. Univariate statistics were performed using two tailed t-test and chi-squared test for continuous and categorical independent variables, respectively. Efficiency scores were calculated as the quotient of stone burden on preoperative CT scan by laser utilization time (mm3/s). RESULTS: One-hundred and forty patients met our study inclusion criteria. Seventy-nine patients underwent lithotripsy with a standard laser fiber and 62 patients underwent treatment with MOSES. There were no significant differences in patient age or comorbidity between the two cohorts. The primary location for most stones were lower pole, renal pelvis or proximal ureter for both cohorts. Mean stone volume was 20.5mm for patients who received MOSES and 18.5mm for patients treated with a standard fiber. The provider estimated post-procedure stone free rate was 95% for all patients. Procedures with MOSES Technology resulted in significantly reduced total operative times (85.9 min vs 98.1 min, p=0.03) and reduced intracorporeal treatment times (38.82 min vs 44 min, p=0.05). MOSES demonstrated improved treatment efficiency (2.4mm3/s vs 1.8mm3/s, p=0.03) compared with the standard fiber. There was no significant difference in estimated post-procedure stone-free rate or staged same laterality procedures. CONCLUSIONS: MOSES Technology demonstrates reduced operative times and intracorporeal operative time during MPCNL. In our series, MOSES Technology outperformed an industry standard holmium laser fiber in treatment efficiency with no significant differences in clinical outcomes Source of Funding: Lumenis Ltd © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e318-e318 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Meagan Dunne More articles by this author Max Drescher More articles by this author Joel Abbott More articles by this author Julio Davalos More articles by this author Expand All Advertisement Loading ...

X-ray Dose Rate and Spectral Measurements during Ultrafast Laser Machining Using a Calibrated (High-Sensitivity) Novel X-ray Detector.

Ultrashort pulse laser machining is subject to increase the processing speeds by scaling average power and pulse repetition rate, accompanied with higher dose rates of X-ray emission generated during laser–matter interaction. In particular, the X-ray energy range below 10 keV is rarely studied in a quantitative approach. We present measurements with a novel calibrated X-ray detector in the detection range of 2–20 keV and show the dependence of X-ray radiation dose rates and the spectral emissions for different laser parameters from frequently used metals, alloys, and ceramics for ultrafast laser machining. Our investigations include the dose rate dependence on various laser parameters available in ultrafast laser laboratories as well as on industrial laser systems. The measured X-ray dose rates for high repetition rate lasers with different materials definitely exceed the legal limitations in the absence of radiation shielding.

Laser Processing Methods for Perovskite Solar Cells and Modules

AbstractThe perovskite photovoltaic technology is now transitioning from basic research to the pre‐industrialization phase. In order to achieve reliable and high‐performance commercial perovskite solar modules, high throughput manufacturing technologies must now be adapted to the specific constraints and requirements imposed by the perovskite solar cells unique new chemistries, film deposition methodologies, and encapsulation requirements. Laser technologies will play an important role in the industrialization of these devices, both to achieve high active surface area modules and for the deposition and/or treatment of the critical layers. Industrial lasers will be essential to achieve active areas greater than 95% of the total area to retain the benefits of the very high performances reported for <1 cm2 laboratory cells. The speed of laser processing for the preparation of interconnects is unrivalled by comparison to other structuring methods. Recent reports of the use of lasers in upscaling perovskite solar cells are presented and analyzed here.

Industrial pulsed laser deposition for ultra-fast growth of high-temperature superconducting thin films with nanostructured pinning centers

Industrial pulsed laser deposition for ultra-fast growth of high-temperature superconducting thin films with nanostructured pinning centers

Speckle-reduced green and yellow-green Nd:YVO4(YAG)/PPMgLN lasers for cinema exhibition industry

For exhibition industry, the application of RGB laser-illuminated projectors has already been demonstrated. However there are still some urgent scientific and technological issues to be solved. In this paper, the speckle issue of green and yellow-green all-solid-state Nd:YVO4 (YAG) / PPMgLN lasers is analyzed. We choose a well-designed multi-emitter array LD as pump sources to reduce the speckle contrast. Because the emitters of the array LD are independent of others, the speckle contrasts of the green and yellow-green lasers have been reduced to 1/24 and 1/6, respectively.

High‐contrast pulse measurements for industrial applications and laser development

High‐contrast pulse measurements for industrial applications and laser development

Principles of laser scanning microscopes

AbstractFunctional materials have been developed and widely used in industrial fields including the automobile, aviation, metal, and chemical industries, requiring high accuracy and resolving power for measurements and testing. This article details the features and applications of industrial laser scanning microscopes, concentrating on the reflection‐type confocal laser scanning microscope built for high resolution detection.

Ultrahigh-Energy Laser-Assisted Exfoliation for Fast Eco-Synthesis of Reduced Graphene Oxide with Structure Quality

The main focus of these investigations is to introduce a simple, eco-friendly technique for producing high quality sheets of reduced graphene oxide (rGO) by applying an ultrahigh energy laser, coupled with sonication, as an energetic thermal effect promoter to replace removal of oxygen by treating graphene oxide (GO) with ordinary thermal treatments or a combination of chemical and thermal processes. The results indicated that doses from an industrial ultrahigh energy laser with an output of 1650W. coupled with sonication, suffice to reduce graphene oxide (GO) and convert it into reduced graphene oxide (rGO) within the range of a 60-minute experiment. Raman spectra, x-ray diffraction and atomic force microscopy were used to confirm the presence and measure the structure quality of the reduced form of graphene oxide. Results obtained confirmed that applied laser doses coupled with sonication succeeded to produce rGO with good structural features.