CO2 Laser Parameters Research Articles

Insights into solid-contact ion-selective electrodes based on laser-induced graphene: Key performance parameters for long-term and continuous measurements.

This work aims to serve as a comprehensive guide to properly characterize solid-contact ion-selective electrodes (SC-ISEs) for long-term use as they advance toward calibration-free sensors. The lack of well-defined SC-ISE performance criteria limits the ability to compare results and track progress in the field. Laser-induced graphene (LIG) is a rapid and scalable method that, by adjusting the CO2 laser parameters, can create LIG substrates with tunable surface properties, including wettability, surface chemistry, and morphology. Herein, we fabricate laser-induced graphene (LIG) solid-contact electrodes using different laser settings and subsequently convert them into ion-selective sensors using a potassium-selective membrane. We measure the aforementioned tunable surface properties and correlate them with resultant low-frequency capacitance and water layer formation in an effort to pinpoint their effects on the sensitivity (Nernstian response), reproducibility (E°' variation), and potential stability of the LIG-based SC-ISEs. More specifically, we demonstrate that the surface wettability of the LIG substrate, which can be tuned by controlling the lasing parameters, can be modified to exhibit hydrophobic (contact angle > 90°) and even highly hydrophobic surfaces (contact angle ≈ 130°) to help reduce sensor drift. Recommendations are also provided to ensure proper and robust characterization of SC-ISEs for long-term and continuous measurements. Ultimately, we believe that a comprehensive understanding of the correlation between LIG tunable surface properties and SC-ISE performance can be used to improve the electrochemical behavior and stability of SC-ISEs designed with a wide range of materials beyond LIG.

ANN Prediction of Laser Power, Cutting Speed, and Number of Cut Annual Rings and Their Influence on Selected Cutting Characteristics of Spruce Wood for CO2 Laser Processing.

In this work, we focus on the prediction of the influence of CO2 laser parameters on the kerf properties of cut spruce wood. Laser kerf cutting is mainly characterized by the width of kerf and the width of the heat-affected zone, which depend on the laser power, cutting speed, and structure of the cut wood, represented by the number of cut annual rings. According to the measurement results and ANN prediction results, for lower values of the laser power (P) and cutting speed (v), the effect of annual rings (ARs) is non-negligible. The results of the sensitivity analysis show that the effect of v increases at higher energy density (E) values. With P in the range between 100 and 500 W, v values between 3 and 50 mm·s-1, and AR numbers between 3 and 11, the combination of P = 200 W and v = 50 mm·s-1, regardless of the AR value, leads to the best cut quality for spruce wood. In this paper, the main goal is to show how changes in the input parameters affect the characteristics of the cutting kerf and heat-affected zones for all possible input parameter values.

Correlation Between the Effects of CO2 Laser and Histopathological Analysis in Vocal Cord Lesions: An Observational Study.

Lasers are based on the principle of light amplification by empowering atoms to store and emit light in a coherent form. Through their effect on tissues, lasers reduce hemorrhage allowing the surgeon to work in a clear field with precise removal of the tissues. Irradiation of the soft tissues by lasers produces thermal effects on the surrounding healthy tissues which can make histopathological examination difficult. Hence this study was done to find a correlation between adjustable parameters of CO2 laser and the extent of collateral thermal damage in the excised vocal cord lesions on histopathological examination and diagnosis. In this study, we enrolled 80 patients who were divided into 4 groups with different combinations of laser power and mode, used during transoral laser micro laryngeal surgery for the excision of vocal cord lesions and subsequent histopathological analysis to objectively measure the extent of thermal damage zone and subjectively assess histo-morphological effects of thermal damage in terms of grade of carbonization. The extent of the thermal damage zone is directly related to the power of the laser, but the mode of the laser had no relation with the thermal damage zone in our study. On subjective histo-morphological examination of excised lesions showed that both power and mode of laser have significant effects on tissue morphology. Continuous mode causes a significantly higher grade of carbonization as compared to the superpulsed mode of the laser. However, in our study it was seen that charring in no way affected the diagnosis in any of the biopsies examined whatever the power or mode of the laser used. The depth and width of the tissue thermal damage zone are mainly dependent upon the laser parameters (power and mode). Although considering the limitations of this study carried out in terms of sample size, it would be pertinent to mention here that further studies with larger cohorts need to be done to authenticate these results.

The Inhibitory Effect of CW CO2 Laser on Carieslike Lesion Initiation on Sound Enamel: an In Vitro Study

Although CO2 laser irradiation can decrease enamel demineralization, it has still not been clarified which laser wavelength and which irradiation conditions represent the optimum parameters for application as preventive treatment. One of the important applications of the laser is as a caries inhibition treatment of the sound dental tissues. This study aimed to assess the caries preventive potential of various CW CO2 laser parameters, and to explore the effect of laser power density, and the exposure time on the caries inhibition activity. Eighty one extracted human premolar teeth were irradiated with three output power: (1, 2, and 4) W, three spot diameter: (2, 2.83, and 4) mm, and three exposure times: (0.2, 0.4, and 0.8) sec of 10.6µm CW CO2 laser. Three teeth were used as a control group. All teeth were subjected to carieslike lesion formation by 3.5 pH lactic acid solution for 21 days. The teeth after that were sectioned into ground cross sections and the lesion depths were measured under polarizing microscope. The lesion depths of experimental samples were compared with those of the control samples. A single exposure to CW CO2 las er irradiation was found to be resulted in reduction of the carieslik e lesion depths. These reductions were up to 61%. The inhibition activity was related directly to the power density and inversely to the exposure time of CW CO2 laser radiation. The optimal parameters were 33W/cm2 power density and 0.2 exposure time. These finding should be reinforced with more laboratory, animal, and human studies with and without fluoride before clinical applications.

Effects of Irradiation of Continuous Wave Carbon Dioxide Laser on Caries Resistance of Deciduous Teeth

The objective of this st udy aimed to assess the caries-preventive potential of various CW CO2 laser parameters, and to explore the effect of the laser power density on the caries inhibition activity.Extracted human deciduous molars were irradiated with three various power dens ities, by changing the output power, the exposure time, and the spot diameter. The CO2 laser system emitted laser with 10.6µm in wavelength. All teeth were subjected to carieslike lesion form ation by 3.5 pH lactic acid for 21 days. The teeth after that were sectioned into ground cross sections and the lesion depths were measured under a polarizing microscope.CW CO2 laser preventive treatments inhibited carieslike lesion progres sion up to 82%. This effect was improved with increasing power d ensity within the limits of the examined laser parameters.

Optimization of Tensile Strength in the Paper Material Cutting Process Based on CO2 Laser Process Parameters

This paper examines the impact of the CO2 laser parameters on the tensile strength, which is one of the most important properties of paper packaging in the process of cutting paper material. The study was performed on a paper material sample Fbb Board/Ningbo Spark C1S Ivory Board by examination of the influence of four independent variables: paper material grammage, cutting speed, laser power, and resolution on the tensile strength by using definitive screening design. Optimum process conditions of four variables that maximize the tensile strength were predicted and validated accordingly. Results confirm that laser power, paper material grammage, and cutting speed are the main process parameters that mostly affect the tensile strength. Besides individual parameters, two statistically significant interactions were obtained: laser power and cutting speed, and cutting speed and laser resolution. Maximum tensile strength values (20.37 N/mm) were achieved using the laser power of 60.6%, cutting speed of 3.24%, resolution of 2500 Hz, and a paper material grammage of 326.85 g/m2. With laser power at middle values and at a lower speed, a maximum tensile strength value can be obtained. Increasing the laser power and cutting speed will produce a slight lowering of tensile strength.

A comparative study on the effect of CO2 laser parameters on drilling process of polycarbonate and PMMA polymers complemented by design expert

In this research, micro-drilling with a CO2 laser was conducted on two types of polymer, polycarbonate (PC) and poly methyl methacrylic (PMMA), due to their desirable chemical and physical characteristics. Design-Expert analysis has been used to better understand the laser drilling process and reduce the number of experiments needed. Based on Box–Behnken design (BBD), the experiments were designed to examine the influence of the laser parameters on the micro-drilling process. The impact of parameters, such as power (P), exposure time (t), and focal plane position (FPP), on the depth, entry diameter, and heat-affected zone (HAZ) was investigated using the statistical analysis technique ANOVA. To conduct virtual tests alongside the experimental study, the temperature distribution of the drilling mechanism was simulated using the COMSOL Multiphysics program. The refined accuracy of the simulation predicted the geometry of the hole and presented outcomes that favorably correspond with the experimental results. Experiments were optimized using numerical optimization to attain the ideal hole in CW mode for various values of laser power, exposure time, and FPP. A significant improvement in hole quality was achieved. The acquired data were validated using confirmation tests. The outcomes for the ideal full hole revealed the minimum HAZ (60 μm), with a minimum diameter (360 μm), and 1 mm hole depth occurred at zero FPP for PMMA, with laser power of 3 W and at 0.17 s. Meanwhile, for PC, the ideal hole with minimum HAZ (90 μm), minimum diameter (350 μm), and 1 mm hole depth was achieved at zero FPP, with laser power of 3.6 W and at 0.1 s.

Influence of Irradiation Parameters on Structure and Properties of Oak Wood Surface Engraved with a CO2 Laser

The work investigates the effects of CO2 laser parameters (laser power and raster density) on wood mass loss in oak wood and impacts on its morphology, chemical structure, and surface properties (colour and hydrophilicity). The energy amount supplied onto the wood surface with a laser beam under different combinations of the irradiation parameters was expressed through a single variable-total irradiation dose. The mass loss was confirmed as linear-dependent on the irradiation dose. With the mass reduction, the roughness was enhanced. The roughness parameters Ra and Rz increased linearly with the mass loss associated with the increasing irradiation dose. The FTIR (Fourier transform infrared spectroscopy) spectroscopy also detected chemical changes in the main wood components, influencing primarily the wood colour space. Conspicuous discolouration of the engraved wood surface was observed, occurring just at the minimum laser power and raster density. The additional increasing of laser parameters caused a novel colour compared to the original one. The detected dependence of wood discolouration on the total irradiation dose enables us to perform targeted discolouration of the oak wood. The engraved surfaces manifested significantly better wettability with standard liquids, both polar and non-polar, and higher surface energy values. This guarantees appropriate adhesion of film-forming materials to wood. Identification of the changes in wood surface structure and properties, induced by specific CO2 laser-treatments, is important for obtaining targeted discolouration of the wood surface as well as for the gluing or finishing of the surfaces treated in this way.

Experimental Analysis of Surface Roughness in the Cutting Process of Sugar Palm Fiber Reinforced Unsaturated Polyester Composites with Laser Beam and Abrasive Water Jet Cutting Technologies

This research aims to investigate the effects of the input parameters on the surface roughness as output parameters of CO2 laser and abrasive water jet (AWJ) machining technologies utilized in cutting sugar palm fiber reinforced unsaturated polyester (SPF-UPE) composite of three specimen thicknesses. The objective of this study is to collect data involve the optimal parameters of these technologies regarding the surface roughness response. The motive was to avoid defects arising use in the conventional cutting techniques. In the AWJ technique, stand-offdistance, traverse speed, and water pressure were chosen as variable input parameters to optimize the surface roughness, whereas laser power, traverse speed, and gas pressure were the variable input parameters in the CO2 laser cutting technique. Taguchi’s approach was used to estimate the input parameter’s levels that produce the best surface roughness. Analysis of variation (ANOVA) was used to determine the contribution of every single input processing parameter to the effect on the surface roughness response. Good surface roughness responses could be attained by applying the optimum input parameters determined in this study. The experimental results of the current research provide practical data for the cutting of SPF-UPE composites with CO2 laser and AWJ machining techniques, and the findings can be used as a good starting point for the testing of other similar composites under the same cutting conditions

Dependence of morphology evolution of fused silica on irradiation parameters of CO2 laser

The influence of CO2 laser parameters on the irradiation effect of the fused silica was studied. The morphological characteristics of fused silica treated by a CO2 laser with varying power and frequency were studied experimentally. The properties of the irradiated area were studied by acid etching and hydrophilicity methods in order to verify the effect of CO2 laser irradiation on the SiO2 network. The temperature characteristics of the irradiated region were also calculated using numerical simulations based on experimental parameters. It indicated that the frequency of the CO2 laser plays a key role in the morphology of the irradiated region, and more attention should be focused on the size of the affected zone after laser irradiation in order to fully understand the irradiation process. The good agreement found between numerical simulations and experimental results provides a reference for further research on the application of CO2 laser heating of fused silica.

STUDY ON A RAPID MANUFACTURING OF DIAMOND MICROMIXER BY CO2 LASER

In this paper, the influence of the parameters of CO2 laser cutting system on the rhombus microchannel is studied. In the experiment, we changed the laser processing speed, laser processing power, and laser processing number of CO2 laser cutting system, and the depth and width of microchannel are studied by changing these three parameters. It is found that the depth and width of microchannel increase with the increase of laser processing number and laser processing power. For example, when the speed is 6[Formula: see text]mm/s and the number of laser processing is three times, the width of microchannel increases from 0.51[Formula: see text]mm to 0.64[Formula: see text]mm and the depth increases from 0.75[Formula: see text]mm to 1.60[Formula: see text]mm with the increase of power. However, the depth and width of the microchannel decrease with the increase of laser processing speed. For example, when the power is 8[Formula: see text]W and the number of laser processing is three times, the width of the microchannel decreases from 0.51[Formula: see text]mm to 0.39[Formula: see text]mm, and the depth of the microchannel decreases from 0.75[Formula: see text]mm to 0.34[Formula: see text]mm.

Enamel erosion prevention and mechanism: effect of 10.6-μm wavelength CO2 laser low power density irradiation studied by X-ray fluorescence and infrared spectroscopy and scanning electron microscopy

This study assessed the effects of carbon dioxide (CO2) laser (λ = 10.6 μm, 5 W, 70 J/cm2) irradiation alone and after treatment with neutral fluoride gel on enamel and their efficacy in preventing enamel erosion compared to untreated and fluoride gel-treated enamel. Enamel surfaces of the bovine incisor (n = 7/group) were treated with artificial saliva (S, negative control), neutral fluoride (NF, positive control), CO2 laser irradiation (L), and NF + laser (NF + L). Samples were acid demineralized (soft drink, pH ~ 3.2, 10 min), remineralized (saliva, 37 °C, 1 h), and analyzed using micro-energy-dispersive X-ray fluorescence spectrometry (μ-EDXRF), attenuated total reflectance–Fourier-transform infrared (ATR-FTIR) spectroscopy, and scanning electron microscopy (SEM). Results suggest that NF gives the best protection against erosion, followed by NF + L and L. μ- EDXRF showed that changes due to laser treatment in L and NF + L were uneven. SEM images showed morphological changes in L and NF + L such as craters, fissures, and roughness in some regions, again indicating the unevenness of laser-induced enamel changes. ATR-FTIR mean spectra intensity levels and principal component analysis also indicate higher efficacy of fluoride over laser treatments and unevenness of laser treatments. Overall, it can be concluded that CO2 laser parameters need to be further investigated to promote adequate protection with minimum surface changes.

Effect of CO2 laser parameters on redwood engraving process complemented by Taguchi method

Laser deep engraving is one of the most promising technologies to be used in wood engraving operations. In this method, a laser beam is used to ablate a solid wood bulk, following predetermined patterns. The sculpture is obtained by repeating this process on each successive thin layer. The degree of precision of the shape, the removal rate, and the surface quality during the engraving process strictly depends on the materials properties, the laser source characteristics, and the laser parameters. This work investigates the influence of the process parameters on the material removal rates by engraving redwood using a co 2 laser working with a wavelength λ = 10.6 µm. The examined parameters were: the laser power, the scanning speed, and line overlapping space; each of them has a different value (20, 25, 30, 35, and 40 W), (100, 300, 500, 700, 1000 mm min −1 ) and (0.03, 0.06, 0.1, 0.2, 0.3 mm) respectively. The working parameters were designed using the L25 Taguchi methodology for the design of the experiment. Experimental results showed that the co 2 laser could successfully engrave the redwood, obtaining different engraving depths. The maximum and minimum depth obtained was 4.25 mm and 0.01 mm. the results show that the engraving depth interaction changes depending on the laser parameters.

A comparative clinical and histopathological pilot study of different fractional CO2 laser parameters in treatment of atrophic linear scars.

Atrophic scars cause significant patient morbidity. Fractional photothermolysis is one of the most effective treatment options used to resurface scars of different etiologies. To assess the efficacy and safety of different fractional ablative CO2 laser parameters in treatment of linear atrophic depressed post-traumatic facial scars in adult male patients. A prospective pilot study of 20 adult male patients (skin types Π- Ⅳ, aged 18-45) with post-traumatic atrophic linear scars were divided into 2 groups each comprising 10 patients receiving different fractional CO2 laser parameters. Both groups received 3 laser sessions, one month apart, and were followed for 2months after the last treatment session. Clinical and histological assessments were done to all patients before treatment and 2months after the last treatment session. Also, patient satisfaction and side effects were recorded. The study showed statistically significant reduction in average scar volume in both groups (P<.01), with reduction in depth more obvious than reduction in width or length in both groups. There was a highly significant difference in overall scar improvement represented by scar volume between both groups (P<.01) with an average reduction in scar volume of 42.85% in group (a) compared with 35.29% in group (b). Also, there was a highly statistically significant increase in both epidermal and papillary and reticular dermis thickness in both groups after treatment. However, the difference between both groups was nonsignificant. Side effects were mild, well tolerated, and transient. Fractional CO2 laser can be utilized as a safe and effective modality in treatment of post-traumatic linear atrophic scars of the face. Adjusting parameters toward increasing depth of penetration and decreasing thermal coagulative effect gives better results.

Effect of gas concentration on the electron transport and the plasma parameters of the CO2 gas mixture

Electron Swarm Parameters in plasma gas mixtures of Co2 have been calculated. Studies focused on four gas mixtures with Co2, He, and N2 in the ratio 5%: 55%: 40%, 2.5%: 45%: 52.5%, 10%: 50%: 40% and 40%: 40%: 20% respectively. Calculations of the electron energy distribution function f (ε), drift velocity Vd, mobility μ, electron diffusion D, D/μ, electron average energy <ε> and electric field E in the range of electric field to gas number density ratio E/N from 1×10−19 to 5×10−15 at 300 0K were reported in this work. The theoretical calculations shown helium has a good effect on the electrons transition parameters of Co2 laser. Furthermore, at low energy, the total collision rate is increasing slowly for higher electron energy.

Дослiдження впливу параметрiв випромiнювання СО2-лазера на процес лазерної обробки полiграфiчної продукцiї

Дослiдження впливу параметрiв випромiнювання СО2-лазера на процес лазерної обробки полiграфiчної продукцiї

Impact of Technological Parameters of CO2 Laser Cutting on oxide adhesion forces on the Base Material

The setting of laser cutting technology parameters affects the resulting state of the final surface. When cutting low-carbon steel using conventional parameters - oxidative cutting, surface oxide layers are formed on the cutting edges resulting from an exothermic reaction by burning material. The oxide layers are undesirable and can cause complications if the components so produced are further coated. The color coat creates an adhesion layer on the surface oxide, and when the oxide has low adhesion to the base material, the paint drops out of the surface with the oxide. Mechanical removal of oxide by grinding, punching or brushing is another manufacturing operation that causes an increase in the cost of production. Chemical cleaning is, in turn, detrimental to workers and is also a burden on the environment. For chemical purification of oxides, phosphoric acid and the like are used. The paper describes cutting low-grade steels in a way that does not require removal of oxides and adhesion bonding between the component and the color coating is sufficient for the use of the component in operation.

Excitation of KdV magnetosonic solitons in plasma in the presence of an external magnetic field

A new mechanism for direct laser energy coupling to heavier ion species in the presence of an external magnetic field has been illustrated. It has been shown that at higher amplitude, the ion disturbances form magnetosonic solitons. A 2D particle-in-cell simulation for an incident laser beam normal to an overdense plasma target in the presence of an external magnetic field has been carried out for this purpose. The external magnetic field is chosen such that the heavier ions remain unmagnetized but the lighter electron species get magnetized at the laser frequency. For conventional lasers of ∼1 μm wavelengths, the magnetic field requirement satisfying the aforementioned condition turns out to be of the order of several hundreds of kilo Tesla. This requirement goes down by one order if pulsed CO2 lasers with wavelengths of ∼10 μm are employed. At present, magnetic fields of several kilo Tesla have already been generated in the laboratory. Keeping this in view, the simulations have been carried out for the pulsed CO2 laser parameters. It is shown that the ion heating is enhanced considerably in the presence of an external magnetic field. Furthermore, it is shown that at a higher intensity of the laser, the ion disturbances acquire higher amplitude to excite Korteweg–de Vries magnetosonic solitons. The solitons, as expected, propagate stably for several thousands of ion plasma periods. However, subsequently, they are seen to develop transverse modulations which grow with time.

Randomized in situ study on the efficacy of CO2 laser irradiation in increasing enamel erosion resistance.

The aim of this double-blind, randomized in situ study was to evaluate the erosion-preventive effect of a specific set of CO2 laser parameters, associated or not with fluoride. Two hundred forty bovine enamel blocks were prepared for individual palatal appliances (n = 6 samples/appliance). The study had four phases of 5days each, with ten volunteers and the following treatments: CO2 laser irradiation (L), fluoride treatment (F), combined fluoride and laser treatment (FL), and no treatment, control (C). Laser irradiation was performed at 0.3J/cm2 (5μs/226Hz/10.6μm) and the fluoride gel contained AmF/NaF (12'500ppmF-/pH = 4.8-6). For erosive demineralization, the appliances were immersed extra-orally in citric acid (0.05M/20min/pH = 2.3) twice daily. Analysis of enamel surface loss was done using a 3D-laser profilometer on 3days. Additionally, fluoride uptake was quantified and scanning electron microscopies were done. Data were analyzed with repeated measures ANOVA and post hoc pairwise comparisons (α = 0.05). At all analyzing days, both laser groups caused the lowest means of enamel loss, which were also statistically significant lower than C (p < 0.05). At day 5, FL means ± SD (33.6 ± 12.6μm) were even significantly lower than all other groups (C 67.8 ± 15.4μm; F 57.5 ± 20.3μm; L 46.8 ± 14.5μm). Significantly increased enamel fluoride uptake was observed for both fluoride-containing groups (p < 0.05) at day 1. Compared to the control, the CO2 laser irradiation with a specific set of laser parameters (0.3J/cm2/5μs/226Hz) either alone or in combination with a fluoride gel (AmF/NaF) could significantly decrease enamel erosive loss up to 5days in situ. Combined CO2 laser-fluoride treatment has a significant anti-erosive effect.

Root Caries Prevention Potential of Chopped CO2 Laser: an In Vitro Study

The objective of this study aimed to assess the caries-preventive potential of various chopped CO2 laser parameters, and to explore the effect of the laser energy density on the caries inhibition activity.Roots of extracted human premolar teeth were irradiated with three various energy densities (25.47, 50.93, and 101.86) J/cm2, by changing the number of pulses, the pulse duration, and the spot diameter. The CO2 laser system emitted laser with 10.6m in wavelength. All roots were subjected to carieslike lesion formation by 3.5 pH lactic acid for 21 days. The roots after that were sectioned into ground cross sections and the lesion depths were measured under a polarizing microscope.Chopped CO2 laser preventive treatments inhibited carieslike lesion progression up to 36%. This effect was improved with decreased total energy density within the limits of the examined laser parameters.