Papers by Keyword: CO₂ Laser

Abstract: Steel alloys made of sheet metal are important materials because of their high strength applications in construction, automobiles, ships, aircraft, and military products. Among the best and fastest non-traditional ways to cut sheet metal these days is laser cutting. Therefore, it's important to comprehend how the parameters of LC affect the quality of the cut. A thorough analysis was provided to find out which LC parameters have the greatest impact on cutting quality as well as how they affect the kerf quality and cut surface. An overview of the benefits of LC over other machining techniques was provided. Furthermore, an explanation of the various laser sources and the laser cutting technique were given. by eliminating each source's spectrum of cut material thicknesses and their benefits. Graphs and formulae provided a detailed illustration of the cutting performance characteristics. Tables and graphs that display the whole classification of the examined papers were used to utilized to arrange the discussion and analysis of the research into such a detailed discussions. It was discovered that Steel alloys are the most commonly used for laser cutting (59%), followed by aluminum alloys (13%) and titanium alloys (12%). While other subjects constitute 16% of research in this field It was also found that The most common parameters utilized as controls are cutting speed (30%), Laser power (23%), Assist gas pressure (21%), Pulse frequency (9%) and Focal position (7%), in general the ideal parameters to achieve low (SR), small (HAZ) width, small (KW) and small (KT) are low (Pu), high (V), medium (P), high (SOD), medium (PF), medium (PW), small (ND), small (T), and N2 as an assist gas.

Abstract: Motivated by a desire to improve hole quality during drilling Polymethyl methacrylate (PMMA) samples using a continuous CO₂ laser. This research presents a theoretical and experimental investigation to optimize input parameters of laser drilling such as laser power and exposure time for different thicknesses 1-3 (mm). Hole quality characteristics such as depth, inlet diameter, and heat affected zone (HAZ) were considered process results and examined with a microscope. Design Expert software has been used to get a detailed understanding of a laser drilling process owing to the confluence of multiple factors that impacts the results. depending on the Box Behnken Design (BBD) of tests software; 17 experiments were applied to explore the effect of laser factors on the micro-hole drilling process. Statistical analysis technique (ANOVA) was used to study the influence of laser drilling process factors including power, exposure time of different thicknesses on HAZ, depth, and entrance diameter. Quadratic regression models were employed to model the processing of many hole variables. Experiments were optimized using the defined goal model as a function to get the optimal hole. The data received were confirmed using verification tests, and a considerable increase in hole quality was realized. The proposed technique is perfect for reducing the HAZ and entrance hole diameter for the ideal depth hole. The laser parameters were changed in different combinations of 2-6 (W) power and 0.1- 0.3 (s) exposure duration, on the various thickness. The obtained values indicated that raising the drilling parameters increases the depth, entrance diameter, and HAZ. The sample thickness has a great impact on hole characteristics; increasing the sample thickness reduces the inlet diameter, and heat-affected zone (HAZ); increasing the thickness leads to an increase in hole depth. The results showed that the highest depth of 1mm thick was 0.99(mm) with 437(µm) diameter and 85(µm) HAZ. 1.9(mm) depth with 435(µm) diameter and 32(µm) HAZ was obtained at 4.99(W) and 0.1(s) on 2(mm) thickness. while as in 3(mm) thick, depth is equal to 2.8(mm), 472(µm) diameter, and 20(µm) HAZ was attained. COMSOL Multiphysics 5.6 software was used to apply virtual experiments and obtain the ideal conditions from the parameters' combination that improves the quality of the hole, which is the main goal of this research. Which is in good agreement with the test results. The findings and procedure of this research have not been presented elsewhere.

Abstract: The work is devoted to the problem of synthesis of coatings based on titanium carbide. Methods for obtaining coatings using femtosecond laser radiation and a CO₂ laser are considered. The differences in mechanisms of titanium carbide synthesis, as well as the areas of application of technologies, are described. The Raman spectra of the obtained coatings are presented and analyzed. It can be judged that as a result of laser treatment, titanium carbide was formed.

Abstract: 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.

Abstract: This study deals with high quality thermal stress cleavage of thick sapphire wafer with thickness of 5 mm. The influence of the distance from the edge to the initial crack, laser power, and plane orientation on the cleavage characteristics was experimentally investigated. The results indicate that the surface waviness W_a at the cleaved surface was influenced by the distance from the edge. A cleaved surface with good surface characteristics was obtained by cleaving with low laser power. The cleavage direction also affects the cleaved surface characteristics.

Abstract: Coatings are applied on turbine blades’ surfaces to provide protection not only against high temperature but also against aggressive environment. Ceramic coatings are employed to avoid metallic substrate overheating, while at the same time increasing turbine work temperature and performance. A bond coat (BC) base of particulate material based on Ni-Al powders is necessary to assure oxidation protection, a good adhesion and gradual decrease in thermal expansion coefficient between the blades’ metallic substrate and the ceramic top coating. One of the most important parameters of such coatings is the adhesion strength. In this work, a NiCrAlY bond coat was deposited on Inconel 625 substrate employing High-Velocity Oxygen-Fuel (HVOF) thermal spraying technology and CO₂ laser beam irradiation to enhance coating–substrate adherence and metallurgical bonding. Microstructural features were examined by optical and scanning electron microscopy (SEM), X-ray diffraction and microhardness analysis. The results indicate that the laser treatment provided an efficient metallurgical bond between the (BC) and Inconel 625 substrate.

Abstract: The development of innovative micro components depends on the manufacturing system and process that reliable to produce the component in micro scale with good quality. In this case, using CO₂ Laser is one of microfabrication techniques to fabricate material to get micro component. In this research, experiment was performed to fabricate micropattern using engraving method by Laser CO₂ machine with several independent variables such as focus distance of nozzle Laser to workpiece (F), power of Laser (P), and velocity of nozzle Laser movement (V). The workpiece in this research was acrylic. Result of fabrication process will be identified and measured using digital microscope and surface roughness tester to get the value of workpiece quality such as surface roughness and geometrical properties as the dependent variables. The relationship of both variables will be expressed in 3D curves characteristic and mathematical models were analyzed by response surface methodology (RSM). The result of the analysis shows that the power of Laser (P) and velocity of Laser nozzle movement (V) effect is the significant variables affecting the quality of micropattern and micromold fabrications. Micromold can be fabricated using Laser CO₂ with roughness value (Ra_x) is 17,55μm, width of grove (W) is 135 μm, depth (D) is 341 μm.

Abstract: Glass-ceramic was precipitated on the oxyfluoride glass surface by thermal annealing with a CO₂ laser and a heat gun. Micro x-ray diffraction showed the formation of CaF₂ ain the exposed region to the laser. Dopant distribution in glass ceramics was probed by confocal fluorescence microscope by observing much strong emission from Eu ions than the glassy area under 405 nm excitation. Much enhanced visible emissions under 365 nm excitation also showed well incorporation of Eu³⁺ ions into a crystalline environment.