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In this research work, the effect of laser cutting parameters on material removal rate of aluminium 5052 is presented. The material removal rate has been analysed using various investigating techniques such as precise measuring scale and optical microscope. The various cutting parameters considered such as cutting speed, laser output power, nozzle stand-off distance and nozzle diameter. The cut quality further investigated for kerf width deviation and surface roughness using one factor approach. Using microstructural analysis, it was analysed that cutting rate and laser power as most significant parameters.

Depending on the stator lamination manufacturing processes (e.g., punching, laser cutting, clamping, welding, interlocking, and bonding), the motor’s magnetic performance parameters, such as cogging torque, hysteresis torque, and iron losses, can vary significantly. In sub-fractional horsepower (SFHP) permanent magnet motors, the manufacturing influence is typically even more severe because, due to their small dimensions, practically, the whole stator material is likely to be affected. This article analyzes the magnetic performance parameters cogging torque, hysteresis torque, and iron losses of three different stator lamination stacks (i.e., M250-35A punched with interlocking, M250-35A laser cut with bonding, and NO10 laser cut with bonding) of an SFHP single-phase brushless permanent magnet motor often found in automotive fan applications. A rheometer is used for extremely accurate torque measurements in the sub-millinewton meter range, and electron backscatter diffraction measurements are performed to visualize changes in the grain morphology and crystal orientation. The findings reveal that the punched stator with interlocking is affected the most by the manufacturing process, showing the lowest cogging torque yet the highest average hysteresis torque and thus up to 40% higher iron losses. The results presented in this article allow for both making basic stator lamination design choices and translating the iron losses, as well as the hysteresis torque and cogging torque waveforms, of a laser cut and bonded prototype into those of its punched and interlocked mass-produced counterpart.

The purification of laser keyhole is an important means to remove the oxide layer of laser-MIG hybrid welding of aluminum alloy. Four common auxiliary gases (argon, nitrogen, air and oxygen) were used to prepare kerf with different characteristics, which were defined as argon-weld, nitrogen-weld, air-weld and oxygen-weld. The results show that the remelted layer has little effect on the weld morphology. Microstructures characteristics of Argon-welds and nitrogen-welds were the same as machined welds, while the narrow columnar grain zone and coarsen grains exist in air-welds and oxygen-welds. When the thickness of kerf remelted layer increases, the width of columnar grain zone is reducing and the diameter of equiaxed grain is increasing. The argon-weld is with the best tensile property. When the thickness of remelted layer (d) is less than 70 μm, the tensile strength and elongation of argon-weld can reach 278 MPa and 3.1% respectively, which equivalent to that of machined weld. The tensile property of nitrogen-weld is slightly lower than that of argon-weld because of aluminum nitride impurities. The tensile properties of air-weld and oxygen-weld are low because of a large number of oxide impurities and grain coarsening. Regardless of the types of kerf, when the d is less than 136 μm, the tensile strength reaches more than 250 MPa, which meets the application requirements.

Nowadays, industrial laser cutting systems employ a fixed set of process parameters throughout the cut of the same workpiece, which results in a good compromise between maximum productivity and surface quality. The process parameters are commonly set by trial-and-error experiments carried out on different materials and thicknesses or less frequently by physical modelling. However, the final cut quality is not constant even though the process parameters are kept fixed due to degradation of the initial status of the laser cutting system. One of the common issues in the laser cutting process is the local heating of the optical components due to contamination and/or high powers commonly employed, which cause shifting of the focus position. This can worsen the cutting-edge quality, and even result with loss of cut. Therefore, the online measurement of the position of focus is a requirement for a consistent process. An empirical method used in the industrial practice for initially setting and successively examining and adjusting the focus position is to measure the kerf width of a straight-line cut performed with constant process parameters. This paper proposes an algorithm to monitor the kerf width and yield the estimated focus position in real-time during the cutting process. The kerf width is observed during the process with a coaxial camera module mounted on the laser head which monitors the thermal interaction between the laser beam and the material. An image processing algorithm was developed for extracting the kerf width from the acquired images, and the algorithm parameters were experimentally calibrated such that the extracted value of the kerf width matches with its physical measure. To understand the influence of the focus position on the cutting kerf, an experimental campaign was conducted and subsequently a regression model was fitted. The real-time monitoring and computation of the kerf width and its correlation to the focus position give the opportunity for a closed-loop control of the focus shift, that would eventually lead to a gain of process stability and repeatability.

The PAM-Stamp 2G software package is used to simulate the tool bending of a workpiece made of an AMg5 aluminum alloy with and without taking into account the heat-affected zone (HAZ) formed during laser cutting of a sheet. The option of calculating welded workpieces is adapted to describe the HAZ. The state of stress in the workpiece during bending at various bending radii is analyzed with allowance for various HAZ widths. The influence of HAZ up to 4.5 mm wide on the workpiece thickness during bending is found to be insignificant.

Simultaneous investigation of kerf quality and fume emissions during laser cutting process is essential to achieve efficient and hygienic cutting process. In this study, an experimental investigation on process factors of CO2 laser cutting (CLC) of polyvinyl chloride (PVC) sheets has been carried out followed by an optimization study to enhance the kerf geometry and reduce the emitted harmful fumes. Laser power, transverse cutting speed, and sheet thickness have been considered as the process factors. The kerf geometry has been measured using optical microscope. The emitted fumes are considered to be proportional to the generated kerf volume. An L9 experimental design plan was designed using Taguchi method, and the results were evaluated using analysis of variance (ANOVA). Second-order regression models have been developed to correlate the input parameters to the process responses. Genetic algorithm (GA) was implemented to obtain the optimum process parameters that should be used to minimize the kerf volume and consequently the emitted fumes. A significant decrease in kerf volume has been obtained using the optimum process parameters. Confirmation experiments have been conducted to verify the accuracy of the proposed approach. The proposed optimization method shows a considerable decrease in the kerf volume and the emitted fumes, especially for large sheet thicknesses. The emitted fumes can be reduced by about 39% and 61% for sheet thickness of 7 mm and 10 mm, respectively, by applying the optimum cutting parameters obtained from this study.

In this study, a series of butt welding tests with oscillating fiber laser beams were performed on zinc-coated thin sheets of 0.8 and 1.2 mm thicknesses. The optimized welding parameters were used to produce robust welds with no perforations or pores. The weld formation process, microstructure, and mechanical properties of welded joints with the butt surfaces processed via laser and shear cutting techniques were systematically investigated. Besides, the corrosion resistance of the laser oscillating welded joint was analyzed in detail. The welded joint with the butt surface processed by laser cutting shows less undercutting degree with a more favorable weld appearance. The two welded joints had similar microstructures containing different forms of ferrites. The heat-affected zone was almost identical to the base metal in microstructure but had larger grains. Widmanstatten ferrites’ content in the large-grained weld metal of welded joints with surface processed via laser cutting exceeded that of shear cutting-processed ones. The former had lower tensile strength than the latter, but their overall mechanical performance was better than base metal. After salt spray corrosion and electrochemical corrosion tests, the laser oscillating welded joint was only slightly corroded and exhibited no obvious deterioration in corrosion resistance.

Thermoplastic polyurethane (TPU) films have been widely used as substrates in the rapidly developing fields of flexible electronics and soft actuators. Patterned high-quality cutting is of great significance to the promotion of applications. In order to clarify the mechanism of laser cutting, Raman and thermal analyses were performed. Raman tests verified that no new solid by-products were produced after laser cutting. Thermal cracking and thermogravimetric-infrared combined analysis were used to simulate the process of nanosecond laser cutting, and the results showed that the gas by-products released were mainly composed of organic substances including ketone and phenol with benzene ring as the main body, as well as low-chain hydrocarbons and alcohols. Moreover, a cutting quality evaluation standard consists of cutting kerf zone (CKZ) and heat-affected zone (HAZ) was established. And based on this standard, the better nanosecond laser cutting parameters are 10 kHz and 0.03 m/s, which was obtained from a 2-factors and 5 levels orthogonal experiment. Main effect and interaction analysis were performed to clarify the impact of laser parameters on cutting quality and each other.

Thermal ablation is an efficient method of medical treatment, such as cancer therapy, wound closure, laser cutting, freckle removal and other treatments. In order to guarantee the curative effect and the safety of the patients, the thermal response of the tissue which is subjected to the heat source need to be carefully monitored. However, it is too difficult to achieve real-time monitoring on the full-field temperature. In the present study, efforts were made to build up a theoretical model for the prediction of the thermal response in the human skin. The Dual-Phase-Lag (DPL) bio-heat transfer model and the Henrique’s burn assessment model were employed to describe the interaction of multi-pulse heat source and the skin. The repeated multi-pulse laser is a common heat source in the thermal treatment and the thermal responses of the skin would be complicated under the common effects of the non-Fourier effects and the multi-pulse source. The Green’s function approach was used to solve the governing equations analytically. The closed-form solution for the temperature distribution of the skin was obtained and the thermal damage was estimated based on the temperature results. The influences of the biological parameters (the phase lags of the heat flux and the temperature gradient) and the heat source parameters (the pulse number and the duty ratio) on the temperature distribution, the burn degree and the irreversible burn depth of the irradiated region were discussed.

During the laser cutting of Ti-6Al-4 V sheets, different dross heights are obtained for different thicknesses of the sheet. The maximum value of normalized dross height (= dross height per unit thickness of laser cut sheet), calculated from reported data, was 0.155. In the present investigation, the maximum normalized dross height, obtained by use of an additional nozzle (secondary gas-flow nozzle) and by parametric optimization through Teaching–Learning-based algorithm, was 0.053. The present study shows that the conventional set-up for laser beam cutting of Ti-6Al-4 V alloy, i.e., cutting with co-axial assist gas flow, may not be able to reduce the dross height completely. However, it was observed that the use of a secondary gas-flow nozzle, in tandem with the co-axial nozzle, i.e., a modified set-up, was able to reduce the dross height due to the shearing action of the argon jet flow directed at the dross. The thrust force of the argon jet acting on the dross has been estimated in the present study using analytical equations and was found to be 76.17 gf. When the longitudinal profile of cut surface was mapped using a laser displacement sensor, it was observed that the roughness of the cut surface obtained using the modified set-up was found to be less (i.e., approximately half) as compared to that obtained in case of the conventional set-up. In addition to the dross height, straightness of the cut sample (kerf wall convexity) was also taken into account for optimization.

The headlights on Anoa 2 6x6 special vehicles are used for street lighting for anoa tanks at night. The purpose of this study was discussed the steps of production process of the Anoa 2 6x6 headlights in PT. Pindad. The headlight component was made in several manufacturing processes that were carried out. It consists of many parts, which a variety of production machines for the manufacture of each part. The manufacturing of the headlight components using machining processes such as laser cutting, welding, and drilling. The type of material used for the manufacture of the headlights and parts that was Aluminum Alloy 2044 and Steel ST-37. The result components were made the headlight frame, BT protectors, the front, side, and rear components.

This paper reports an experimental investigation on continuous CO2 laser cutting of polymethylmethacrylate (PMMA) sheet. The influence of four process factors (laser power, cutting speed, assisting gas pressure and sheet thickness) on five process responses (kerf deviation, top heat affected zone, bottom heat affected zone, maximum surface roughness and rough area) has been investigated. The experimental plan was established based on Taguchi L18 mixed design. The kerf geometry and heat affected zones have been measured using polarising light microscopy technique, while the surface roughness was evaluated using 3D laser scanning confocal microscope. Regression models have been derived to correlate different process responses with different process factors. The cut surface could be classified into three zones: rough zone, moderate zone and soft zone. The rough area is increased by increasing gas pressure and laser power and by decreasing the sheet thickness and cutting speed. Increased kerf deviation has been observed at high cutting speed, laser power and gas pressure. High laser power and low cutting speed produced worst surface roughness and wide heat affected zone. Therefore, it is recommended to use low laser power and high cutting speed to minimize the heat affected zone and the surface roughness. However, increasing the cutting speed may result in high kerf deviation.

By structurally and practically analyzing the use of Nd: YAG laser for cutting black walnut veneer, this study considered practical and environmental concerns regarding the global warming protection measures. A numerical model of laser wood veneer cutting was based on the relation between process parameters and the material thickness. A pulsed Nd: YAG was used to cut black walnut veneer of 0.3 mm thickness under different machining conditions regarding laser power and cutting speed to study the cut kerf width. An analysis of variance was conducted to test the significance of machining parameters. The parameters studied were laser power, cutting speed, kerf width, cut surface, safety, and eco-friendliness. The results showed that the kerf width decreased significantly with increased cut speed and, inversely, by laser output power. An efficient cut with a narrow kerf, clean and smooth, with less burn, was possible at laser cutting speeds of 2.5, 5.0, and 5.5 mm/s with kerf widths of 0.544, 0.69, 0.62 mm, respectively. As multiple factors affect the micro-thin wood laser cutting process, finding the optimal process parameters is crucial for successful machining with no burn effect.

Solar rolled glass, with one micro-structure surface and another roughness surface, can cause diffuse refraction of the focused laser spot, and this phenomenon restricts the application of laser manufacturing. In this study, laser cutting of solar rolled glass with a thickness of 2.5 mm was successfully achieved with the help of dimethicone to ensure laser focusing. Dimethicone was coated on the top surface of the rolled glass processing zone, and a Z bottom—up multilayer increment with the X–Y spiral line was applied to control the cutting path. Different viscosity values of dimethicone were considered. Results showed that surface quality increased as the viscosity increased until a certain threshold was reached; afterward, the surface quality decreased or directly caused the cutting to fail. The minimum surface roughness (3.26 µm) of the processed surface (chipping: Width ⩽ 113.64 um, area 215199 µm2) was obtained when the dimethicone viscosity and laser pulse frequency were 1000 mm2/s and 43 kHz (power 25.4 W), respectively. The micro-defects on the processed surface were few, and the edge chipping width and depth of the laser processed surface were small.

Some important properties of the metal foams that make them attractive materials for various purposes are their excellent stiffness to weight ratio (light-weight structure), ability to take up strain by crushing at controlled pressure (energy and impact absorption), order of magnitude higher damping capacity as compared to the solids (mechanical damping), higher natural flexural vibration frequencies (vibration control), reasonable sound absorbing capacity accompanied by durability and fire resistance (acoustic absorption), and, high area of contact accompanied by high thermal conductivity (heat exchanger). Often foam is joined or connected to cover sheets of the same metal and the whole part together is called a foam sandwich. Among all the metal foams aluminium metal foam has found the widest and diverse application. This article covers important recent literature on laser processing viz. laser forming, laser welding, laser cutting and laser additive manufacturing of metal foams. Prior to this, a link is established between foam/foam sandwich and laser processing techniques stating the limitations of other relatively more conventional processing techniques. Future research direction regarding different laser processing techniques using metal foams has also been outlined.

HighlightsA rapid manufacturing method for internal and external rectangular spline shafts for use in agricultural machinery was developed using a combination of laser cutting and welding.The shear strength of the internal spline welds, extrusion strength of the spline tooth surfaces, and extrusion and shear strength of the external spline pins were tested.Threshold values were obtained for the average diameter of the internal and external splines.Two case studies (light load and heavy load) were performed to verify the feasibility and reliability of the method.Abstract. In recent years, special-sized spline shafts and gears have been widely used in the trial production of new agricultural machinery in China. However, due to the high production cost and long development cycle of these common components, the development of new agricultural machinery has been affected. To solve these problems, this article proposes a method for rapid manufacturing of rectangular internal and external splines using a combination of laser cutting and welding. Through analysis of the weld shear strength of the internal splines, the extrusion strength of the spline tooth surfaces, and the extrusion and shear strength of the external spline pins, it was calculated that the threshold of the average diameter (dm) of the internal splines, commonly used in agricultural machinery, was dm = 31.17 mm, and that of the external splines was dm = 33.45 mm. The feasibility and reliability of the method were verified with two case studies using light and heavy load conditions. The light load case study was the splines of the power input shaft of the pickup platform of a peanut harvester, and the heavy load case study was the splines of the total power input shaft of a peanut no-till planter. The case studies indicated that under the light load conditions (average power of 1.13 kW, average torque of 64.1 N·m, average speed of 168.7 rpm, cumulative working time of 48 h, and harvested area of 46.4 ha) and heavy load conditions (average power of 89.36 kW, average torque of 1029.9 N·m, average speed of 828.6 rpm, cumulative working time of 51.5 h, and planted area of 31.7 ha), no spline failure was observed, and the reliability was 100.0%. This article provides a technical reference for the rapid production of special-sized rectangular splines as single pieces or in small batches for trial production, which requires low processing accuracy, of new agricultural machinery products. Keywords: Agricultural machinery, Laser cutting, Manufacturing method, Rectangular spline, Strength test, Torque.

The magnet-assisted laser hole-cutting in magnesium alloys was explored systematically with and without using water immersion, including femtosecond laser multilayer center-oriented hole-cutting and millisecond laser helical hole-cutting of both blind holes and through holes. The effect of the magnetic field and water immersion on laser hole-cutting quality, efficiency and performance is first reported for magnesium alloys with mechanism analysis and comparable discussion. It was shown that the magnetic assistance and/or the water medium improved the hole wall formation especially for underwater laser cutting of blind holes. Compared to laser hole-cutting in air, the underwater laser hole-cutting generated higher-quality holes in magnesium alloys. For laser hole-cutting in magnesium alloys in water, it is first reported that the magnetic field increases the entrance diameters for blind and through holes while decreases the blind-hole depth. The water cooling-insulating effect prevented the molten and vaporized material from re-solidifying and re-depositing onto the workpiece, and the laser-induced ignition and explosion were also prevented by water. The local laser-induced ignition and explosion were weakened when increasing the magnetic flux density. The local oxidation and carbonization reactions in air as a result of the laser-induced ignition and explosion were suppressed while the laser hole-cutting efficiency was enhanced by using the transverse magnetic assistance. The blind-hole recast layer was significantly reduced nearly without accumulated residues and carbonized or oxidized debris by using underwater laser hole-cutting, indicating that the water suppressed the laser-induced melting, vaporization, ignition and explosion and blocked the re-solidification and re-deposition surrounding the hole entrance and onto the hole wall for the recast layer formation. The average grain size number in the heat affected zone (HAZ) near the hole was improved for grain refinement by increasing the magnetic flux density, demonstrating the magnetic field-induced reduction for the local excessive thermal effect of the femtosecond laser-generated plasma on laser hole-cutting and recrystallization. The micro hardness was improved after laser hole-cutting with and without magnetic assistance mainly due to the HAZ recrystallization-induced grain refinement, and the hardness value roughly increased with the magnetic flux density.

In modern engineering industries, unconventional machining methods are applied to form the hard material. Laser machining is used to cut the hard material with accuracy. The cutting experiment is conducted on strenx 900 steel plates. The experiment is processed under some factors such as cutting angle, cutting speed and laser power. Computer Numerical Control (CNC) laser cutting machine was used to cut the strenx steel plate. The cutting quality is confirmed through measurement of Surface Roughness (SR). The result is analyzed and it is determined the best cutting quality which is derived from taguchi technique. The parametric effect is studied through variance analysis and interaction plot.

Turbine blade cores are made of porous alumina ceramic and determine the molding accuracy of the cavity of turbine blades, which strongly affect thermal diffusion performance and service life of turbine engines. To get a high quality ceramic core, accurate trimming for a preliminarily processed core is needed and therefore, micromachining porous alumina ceramic, which differs from general alumina substrates, is crucial. This paper dealt with a processing technology for the special material via double femtosecond laser scanning. The materials ablation threshold was firstly determined through parameter fitting and then this material was machined at a combination of different laser processing parameters. Considering the produced debris blocks the lasers further propagation into the material, double femtosecond laser scanning was newly proposed and experimentally verified with the comparison of gas jet assist and underwater laser processing ways. The removal profiles of the machined material were characterized in terms of cutting width, cutting depth, deviation of linearity and surface morphology, which exhibited high dependence on the femtosecond laser processing parameters. The optimal laser operating window was identified and high quality laser cutting of the porous alumina ceramic was demonstrated. The developed processing technology has potential application in trimming for ceramic casting cores. In addition, it might also give a novel view for high quality laser micromachining another materials.

The geometrical feature kerf deviation is an undesirable characteristic during machining which is required to be minimized. To minimize kerf deviation characteristics, it is important to select proper machining parameter for machining the workpiece material. Therefore, an investigation is carried out to see the effect of laser process parameters, i.e., “laser power”, “cutting speed”, “gas pressure”, “working distance” and “focus position” on the desired characteristics i.e top kerf deviation and bottom kerf deviation. To achieve the current objective, an experimental investigation is done on CNC based Prima 4000 W CW-CO2 laser cutting process to machined Hastelloy C- 276 material. Using desirability approach of RSM for material Hastelloy C276, the value of the optimum responses top kerf deviation and bottom kerf deviation obtained are 0.0092 mm and 0.0081 mm respectively. The corresponding value of error obtained as 9.7% and 8.6% respectively. Finally, confirmatory test are performed to validate the result obtained using desirability analysis of RSM. The result of confirmatory test shows that percentage error is

High energy density laser beam is a best approach to cut difficult- to- laser cut materials. Laser is most suitable to cut highly reflective and thermal conductive materials i.e. Aluminium and its alloy which is difficult to laser cut material. The optical and thermal characteristics of material are the main proficiency of laser beam machining. The industries as automobiles and aircraft which need complicated design or difficult portrait forward with inflexible model condition adopt that types of material extensively. The quality of laser cutting mainly possible with the appropriate selection of input process parameters. For optimal setting of process parameters, the effect of their variation on different quality characteristics of interest is required to be investigated. In this paper the simulation test results show that the simulated values of material removal rate (MRR) using neural network model are quite close to the values calculated with theoretical formulae. To express the relation between cutting quality and cutting specification the artificial neural network (ANN) approach is established for vertical laser cutting position. For optimizing the parameters, concluding cutting results and surmising new cutting information the artificial neural network (ANN) provides outstanding outcomes.

This paper presents experimental and theoretical studies on the UV laser cutting of beech plywood. The multi-technological factors in the laser cutting process were determined using Taguchi’s parameter design approach. The study of the wood material after laser cutting, related to its microstructure, surface morphology, and surface energy, is included. Beech plywood components were cut using pulsed UV lasers with varying parameters to determine superior surface quality, based on SEM, gray level, water contact angle, and optical profiling. The results showed that the surface roughness, in Ra, of beech plywood components at different laser powers, with and without a gas flux control system, can be reduced from 17.3 to 11.1 μm. The burn marks of the laser cut samples were also characterized in terms of gray level estimation. The results indicated that the gray level of the samples was increased by about 16% with a gas flux control system, implying a lesser extent of the burn marks in the plywood. The proposed laser cutting approach was proven to be successful in controlling the surface finish quality of beech plywood components.

Cutting quality and efficiency have always been important indicators of glass laser cutting. Laser scanning modes have two kinds, namely, the spiral and concentric circle scanning modes. These modes can achieve high-performance hole cutting of thick solar float glass using a 532-nm nanosecond laser. The mechanism of the glass laser cutting under these two different scanning modes has been described. Several experiments are conducted to explore the effect of machining parameters on cutting efficiency and quality under these two scanning modes. Results indicate that compared with the spiral scanning mode, the minimum area of edge chipping (218340 µm2) and the minimum Ra (3.01 µm) in the concentric circle scanning mode are reduced by 9.4% and 16.4% respectively. Moreover, the best cutting efficiency scanning mode is 14.2% faster than that in the spiral scanning mode. The best parameter combination for the concentric circle scanning mode is as follows: Scanning speed: 2200 mm/s, number of inner circles: 6, and circle spacing: 0.05 mm. This parameter combination reduces the chipping area and sidewall surface roughness by 8.8% and 9.6% respectively at the same cutting efficiency compared with the best spiral processing parameters. The range of glass processing that can be achieved in the concentric circle scanning mode is wider than that in the spiral counterpart. The analyses of surface topography, white spots, microstructures, and sidewall surface element composition are also performed. The study concluded that the concentric circle scanning mode shows evident advantages in the performance of solar float glass hole cutting.

A shingled module fabricated using electrically conductive adhesive (ECA) can increase the light-receiving area and provide greater power than a conventional module fabricated using solder-coated copper ribbons. However, several issues such as damage from laser cutting and poor contact by the conductive paste may arise. In this study, a 15.675 × 3.1 cm2 c-Si cut cell was fabricated using a nanosecond green laser, and cell bonding was performed using ECA to fabricate shingled modules. If the laser process was performed with high speed and low power, there was insufficient depth for cut cell fabrication. This was because the laser only had a thermal effect on the surface. The cell was processed to a depth of approximately 46 μm by the laser, and it could be seen that the laser cutting proceeded smoothly when the laser process affected more than 25% of the wafer thickness. The cut cell was bonded by ECA, and the process conditions were changed. The highest efficiency of 20.27% was obtained for a cell bonded under the conditions of a curing time of 60 s and curing temperature of 150°C. As a result, the efficiency of the bonded cell was increased by approximately 2.67% compared to the efficiency of the conventional cut cell. This was because the shadow loss due to the busbar was reduced, increasing the active area of the module by eliminating the busbar from the illuminated area.

For industrial contouring and machining applications such as laser cutting, it is desirable to be able to bound errors without unduly compromising machine throughput. Traditional control architectures in machining are unable to explicitly bound tracking errors, and therefore, conservative operation is required to ensure satisfactory performance of the overall system. This is particularly relevant in contouring applications when the end effector is connected to the drive via a flexible link, and no direct feedback measurement about the end-effector position is available. In this article, a model predictive approach is proposed, which guarantees that a desired level of tracking error is met for the case where the structure is flexible and the end-effector position is estimated. To achieve this, a robust control invariant set is estimated using a computationally tractable algorithm and incorporated into the problem formulation. The applicability of the proposed approach is successfully demonstrated via simulation and experiments conducted on a commercial single axis system.

In this article, authors have made an attempt to cut 1.35 mm thick hybrid Kevlar/Basalt fiber reinforced polymer composite laminate by a 250 W pulsed Nd:YAG laser system. The effects of leading laser cutting parameters, viz. lamp current, pulse width, pulse frequency, compressed air pressure and cutting speed, on cut surface geometry defined by the kerf width, kerf deviation, and kerf taper have been investigated. The effects of laser cutting parameters on kerf characteristics have been discussed by using mean interaction plots of experimental data. Moreover, Firefly algorithm technique has been employed to ascertain the optimal levels of the control parameters to attain better geometry of the cut surface. Significant overall improvement is achieved in the kerf quality characteristics at the optimum levels of process parameters. Lower levels of cutting speed, moderate levels of lamp current, pulse width, and higher levels of pulse frequency and compressed air pressure in the present range have resulted in narrow kerf width with reduced deviation and taper.

Laser cutting of composites such as epoxy based glass fiber and carbon fiber composites using pulsed lasers is discussed. Material characteristics are modified by the addition of nanoclay to the glass fiber composite. The heat affected zone (HAZ) reduced by 40% due to the addition of nanoclay. The dispersion of clay (2 wt% of the matrix) in the epoxy resin matrix not only provides good adhesion between matrix and fiber but also restricts the thermal diffusion hence reducing the area of HAZ. Micro channels fabricated using 120 ns Yb3+ fiber laser with a wavelength of 1060 nm had a distorted channel in glass fiber reinforced plastic (GFRP) and a very large heat affected zone in carbon fiber reinforced plastic (CFRP). Nd3+:YAG laser with a wavelength of 532 nm and 6 ns pulse width produced uniform channels with reduced heat affected zone in both GRFP and CFRP. In addition, laser cutting is performed via multi pass scribing using 6 ns pulse width and a uniform kerf width of 300 μm is observed.

Unsupported combustion nitrogen (N2) and flame-retardant helium (He) were used to facilitate laser-cutting of cherry wood, and the effects of process parameters, gas flow, and gas reactivity on the surface quality of thin wood were studied. Using identical processing parameters, the cherry wood was laser-cut with and without the added gases. Through comparing the cutting width, heat affected zone (HAZ), and surface burning conditions under different gas-assistance conditions, the influence of the added gases on the gasification and combustion of cherry wood was analyzed. When N2 gas was used, the cutting width was less than that of laser direct cutting, but the surface of the burning area did not remarkably improve. Under the same conditions, when He gas was added, the burning areas on both sides of the kerf were remarkably reduced and the consistency of kerf was good. This indicated that He gas had good oxygen isolation and flame-retardant effects. The surface of the kerf was observed with a scanning electron microscope, and addition of He gas remarkably improved the burning that occurred when cutting kerf. This study combined gas processing and laser technology, and it provided technical references for reducing post treatment improving the surface quality of laser-processed wood.

Laser processing is an effective way for precisely and accurately removing a small region of materials without tool wear. Conventional laser processing, which has a limitation on the processing speed, is performed by scanning a single spot on a target material. For improving its speed, a high-power laser beam can be spatially distributed using a hologram to simultaneously process a two-dimensional area. This technique has been used in experiments such as drilling, patterning, etc. However, as far as we know, due to several difficulties, no experiments have been reported that apply the holographic technique to non-scanning cutting with a single hologram. In this research, we experimentally performed non-scanning 2-D laser cutting of a polyimide film by using a single computer-generated hologram (CGH) and a high-power laser of 120 W. To do this, we designed a CGH to reconstruct twelve lines in a 24 mm × 23 mm area. This was then fabricated with fused silica so that it would not be damaged by the high-power laser. This method makes possible the achievement of a high throughput in a material cutting process by utilizing a high-power laser efficiently.

Underwater laser machining process is an alternative method to cut materials with less thermal damage due to the water cooling of workpiece during the ablation. However, the rapid cooling induced by water can instantly solidify the laser-molten material rather than expel it to form a cut. To understand the roles of processing temperature on ablation performance in water, this paper presents the influences of water temperature on cut width, depth, and surface morphology in the underwater laser grooving of silicon. The effects of laser power, laser traverse speed, and number of laser passes on the groove characteristics were also examined in this work. The results revealed that using high water temperature can increase the groove aspect ratio, particularly when high laser power, slow traverse speed, and multiple laser passes were employed. However, debris deposition and oxides were found on the laser-ablated surface when processing at high water temperature. The implication of this study could enhance the ablation rate for the underwater laser as well as low-power laser cutting systems.

This paper investigates the effect of the laser cutting parameters on the heat-affected zone, and on the boundary layer of stainless steel processing. A new analytical resolution based on the boundary layer theory is used to deduce the interaction effects of the cutting parameters on the above zones. The results revealed that, the laminar nitrogen assist gas has a negligible effect on the HAZ depth but it has a remarkable effect on the molten boundary layer. It is also noticed that the pressure gradient remains very small compared to the interface shearing and the conductive heat losses from the cutting zone towards the substrate is dominant compared to the convective heat losses towards the gas.

The process of laser cutting by (Nozzle C 20E) can detect the roughness of the surface from the upper side, while laser cutting by (Nozzle C30E) have less roughness detection according to the ability of constant speed with different metal thickness. The width of the Kerf and surface roughness are the most factors which needs for focusing during cutting process for various plate cutting operation by CNC machine. Such machines require oxygen and propane or acetylene gases with proper pressure controls. For the gas cutting machine, the volume of oxygen gas used is more than that of propane gas. The oxygen gas is used for heating and cutting the plates. It is necessary to supply the proper amount and quality of gas to the machine to obtain a good cutting quality surfces. However; the pressure of oxygen gas depends upon the thickness of cutting plates. Stainless steel is the most important metals in the industrial and manufacturing process, so the cutting conditions are very important. Its concluded from our result, that the characteristics of the main selecting factors which effects the laser machine performance such as, the focal lens nozzle height (0.6 to 1.0mm) and the ability and speed of cutting should be fixed and not changing.

For nuclear decommissioning, the formation of secondary wastes has to be avoided to minimize the need for water and air filtering. Aiming at the minimization of material loss at cutting assignments, this study deploys an Yb:YAG laser for the underwater laser cutting of AISI304 (SS304) stainless steel samples with a thickness of 3 mm used in a range from 2 to 4 kW. Compressed air and nitrogen are applied as the cutting gases with a maximum of 6 bar. For studying the generation of waste material in the surrounding water, the influence of the process parameters on the kerf properties has been studied. Therefore, the characteristics of the resulting kerfs, particularly the weight loss and the occurring dross, were categorized and classified with respect to the weight loss of the samples. Regarding the application of nuclear decommissioning, a weight loss of more than 95 % compared to conventional saw cutting was obtained due to the formation of adhering dross.

An annular intensity distribution has been assumed theoretically with great potential to provide high quality improvements to the cut flank during laser cutting process. We introduce several optical concepts to realize an annular intensity distribution with a high-power laser beam, such as an optical fiber with an annularly formed fiber core, a diffractive optical element, and axicons. Furthermore, cutting experiments for an axicon telescope with stainless steel are presented. With a specific optical setup and appropriate cutting parameters, a burr free cut flank with a surface roughness comparable to the state of art could be achieved. By means of cut front analysis, we assume that the burr free cut flank is a result of an improved gas coupling and the change of cut front geometry at the bottom side of the sheet.

The formation of keyholes during high-irradiance laser-metal interaction is the complex, multiphysics phenomenon that underpins industrial processes such as laser-based additive manufacturing, laser welding, and laser cutting. The complex dynamics of energy coupling in keyhole formation are not well understood, and the energy absorptance in these processes are often assumed to be constant. Therefore, we implement two state-of-the-art measurement techniques in operando to simultaneously measure keyhole depth using inline coherent imaging and laser energy absorptance using integrating sphere radiometry at imaging rates of 200 kHz. Results directly reveal the time evolution of cavity-enhanced absorptance in these keyholes generated by the laser-metal interaction. For stationary irradiance on AISI 316 stainless steel, we find that processing in an argon-rich environment compared to air reduces coupling efficiency by 50 % ± 11 % in conduction, 27 % ± 2 % in transition, and 8 % ± 3 % in keyhole mode. High imaging rates allow clear observation of liquid surface oscillations and corresponding changes to absorptance, declining from 15 kHz to 10 kHz over the first 10 ms of the spot weld.

An underexpanded jet has typical shock-cell structure and strongly oscillates, its behavior being known to cause many industrial problems. An underexpanded jet radially issues from intake and exhaust valves of an internal combustion engine, a pressure control valve and so on. When a supersonic jet exhausted from a circular nozzle impinges on a flat plate, the wall jet formed on the plate often becomes underexpanded and spreads out radially. Such underexpanded impinging jet is one of models of supersonic jets on laser cutting process and glass tempering process. In this study, an underexpanded jet radially discharged from a circular slit nozzle, which consists of two cylinders, was experimentally examined for different nozzle pressure ratios and for different diameters of cylinder. Jet structure was analyzed by means of a visualization e.g. Schlieren method. A noise emitted from the jet was measured and the frequency of screech tone was analyzed. The experimental results were compared with those of a two dimensional jet issuing from a rectangular nozzle. Furthermore, a comparison of visualized sound waves with the screech tone frequency reveals that the sound source measured was in the vicinity of the end of the second cell and that the length of the second or third cell was one of the most important parameters to determine the frequency of the emitted screech tone.

Subject and Purpose. Emission spectra of copper-silver alloys are examined for various recording durations. The radiation coming to the photodetector of the spectrometer consists of the reflected laser radiation and the line spectra of vapors formed by the test substance and the heated material in condensed phase. As the spectrum recording time increases, the background component builds up substantially. The purpose of the work is to study the interaction conditions of millisecond laser pulses with the metals and determine recording time parameters of the optical radiation signal in an effort to achieve an optimal recording of the emission spectrum in the range 400…800 nm Methods and Methodology. The main problem with emission spectrum recording is a persistent thermal component. The laser pulse shape for the optimal recording of the emission spectrum is theoretically calculated. The purity of the emission spectrum depends on its recording duration. The matter of persistent thermal component minimization in laser emission analysis implies the optimal shaping of the laser pulse and its maintenance during the operation. Empirical guidelines exist that the optimal time of the emission spectrum recording is 1...3 ms at a laser pulse duration of 5 ms. Results. It has been found that the main factors affecting the intensity ratio of the continuous and line spectra are thermophysical properties of the metal and a laser pulse shape, especially the value of its trailing edge steepness. Lasers with quasi-optimal pulse shape enable us to increase a maximum frequency of optimal emission-spectrum recording in laser emission analysis. For a 3 ms duration and a 10 J energy of the pulse, the maximum laser frequency at which the laser emission analysis is still possible can be 70...75 Hz. Conclusion. The process of laser emission analysis optimization consists in optimal laser pulse shaping and its maintenance during the operation.

Ceramic coating applied to a metallic base increases its properties such as thermos-stability, corrosion resistance and surface hardness. Ceramic materials inherent brittleness properties implies many difficulties in their mechanical machining processes when a proper shape is required, fact that limit their applications. The complex system analyzed in this paper is formed by a metallic substrate and an alumina ceramic layer obtained through atmospheric plasma pulverization. Laser cutting was performed in order to analyze the behavior of the ceramic layer of 30 and respectively 60 µm in the cutting process. Structural, morphological and chemical evaluation of the cutting kerf was realized using optical microscopy (OM+digital camera), scanning electron microscopy (SEM VegaTescan LMH II, SE detector) and energy dispersive spectroscopy (EDS Bruker X-flash). This analysis highlighted the type of defects along the cut, respectively the phenomena occurring at the ceramic - metal interface.

Laser cutter is a technology that uses a laser for cutting, boring and engraving the materials. The accuracy of laser cutter technology is high compared to other traditional technology. It is used in industrial manufacturing applications and also commercials purpose. Laser cutter works by directing the laser through optics and controlled by the control system by following a G-code of the pattern to be cut onto the material. In this project, a 20w laser, low weighted parts and simple mechanism is implemented to make a portable laser cutter. Also, a separate power controller is provided for laser and the stepper motors. Hence, accuracy is obtained by adjusting the power supply of laser. By using the LIGHT BURN software, the G-CODE is generated to navigate the laser head. The images and impression designs are imported to the software to generate the G-CODE and navigate the laser head. In this software, output power of the laser is also controlled. The materials like wood, fibers can be cut efficient in 20w laser.

Laser cutting is a materials processing technique used throughout academia and industry. However, defects such as striations can be formed while cutting, which can negatively affect the final quality of the cut. As the light-matter interactions that occur during laser machining are highly non-linear and difficult to model mathematically, there is interest in developing novel simulation methods for studying these interactions. Deep learning enables a data-driven approach to the modelling of complex systems. Here, we show that deep learning can be used to determine the scanning speed used for laser cutting, directly from microscope images of the cut surface. Furthermore, we demonstrate that a trained neural network can generate realistic predictions of the visual appearance of the laser cut surface, and hence can be used as a predictive visualisation tool.

In this work, we present femtosecond laser cutting of microchannels in a nodeless antiresonant hollow-core fiber (ARHCF). Due to its ability to guide light in an air core combined with exceptional light-guiding properties, an ARHCF with a relatively non-complex structure has a high application potential for laser-based gas detection. To improve the gas flow into the fiber core, a series of 250 × 30 µm microchannels were reproducibly fabricated in the outer cladding of the ARHCF directly above the gap between the cladding capillaries using a femtosecond laser. The execution time of a single lateral cut for optimal process parameters was 7 min. It has been experimentally shown that the implementation of 25 microchannels introduces low transmission losses of 0.17 dB (&lt, 0.01 dB per single microchannel). The flexibility of the process in terms of the length of the performed microchannel was experimentally demonstrated, which confirms the usefulness of the proposed method. Furthermore, the performed experiments have indicated that the maximum bending radius for the ARHCF, with the processed 100 µm long microchannel that did not introduce its breaking, is 15 cm.

Laser cutting machines are commonly used in wood processing to cut and engrave wood. In this paper, we propose a method and workflow for producing various sensors and electrical circuits by partially carbonizing the wood surface with a laser cutting machine. Similar to wiring on a conventional printed circuit board (PCB), the carbonized part functions as a conductive electrical path. Several methods for creating small-scale graphene by using a raster-scanning laser beam have been proposed; however, raster-scanning requires a substantial amount of time to create a large circuit using carbon. This paper extends the method with a defocused vector-scanning CW laser beam and reduces the time and cost required for fabrication. The proposed method uses an affordable CW laser cutter to fabricate an electrical circuit including touch sensors, damage sensors, and load sensors on wood boards. The circuit can be easily connected to a common one-board microcontroller using metal screws and nails typically used in DIY woodworking.

Laser cutter users face difficulties distinguishing between visually similar materials. This can lead to problems, such as using the wrong power/speed settings or accidentally cutting hazardous materials. To support users, we present SensiCut, an integrated material sensing platform for laser cutters. SensiCut enables material awareness beyond what users are able to see and reliably differentiates among similar-looking types. It achieves this by detecting materials’ surface structures using speckle sensing and deep learning. SensiCut consists of a compact hardware add-on for laser cutters and a user interface that integrates material sensing into the laser cutting workflow. In addition to improving the traditional workflow and its safety1, SensiCut enables new applications, such as automatically partitioning designs when engraving on multi-material objects or adjusting their geometry based on the kerf of the identified material. We evaluate SensiCut’s accuracy for different types of materials under different sheet orientations and illumination conditions.

Laser Safety in Specialized Applications reviews laser applications in a wide variety of fields where lasers have a real impact and potential for hazard but safety is rarely addressed. Those working in fields including astronomy, forensics, art restoration, LIDAR, and underwater will find the book essential. This book gathers a collection of guidelines specific to each application field covering the whole range of common specialized applications, resulting in a practical laser safety manual. This important book provides:Essential guidance for working safely with lasers in these applicationsHighlights of laser use concerns in industries not addressed in typical laser safety trainingDiscussions on the latest best practices and how to investigate laser related incidentsAwareness of laser applications in fields ranging from underwater to outer space Laser Safety in Specialized Applications is for laser equipment operators, scientists and technicians working with lasers, and laser safety officers and consultants.

Laser cutters are currently finding their way from industrial environments to home-use applications, driving the development towards low-cost and compact systems. We therefore target the design of a single beam-shaping lens for use in laser cutting applications, enabling the miniaturization of the laser scanning head while pursuing optimal cutting performance. Particularly, we target the design of a beam shaping lens for use with a high-power 450 nm laser diode (5.0 Watt, 14° x 46° beam divergence), enabling to transform the divergent elliptical laser diode beam into a circular focused spot, while maximizing the depth-of-focus. We cover the complete development chain, starting from the characterization and modelling of the laser diode, to the optical design, optimization and tolerancing of the focusing lens, and the manufacturing and demonstration of the laser cutting system. The optimized beam-shaping lens features a circular focused spot diameter

An attenuator supporting meander-line (ASML) slow wave structure (SWS) is proposed for a Ka-band traveling wave tube (TWT) and studied by simulations and experiments. The ASML SWS simplifies the fabrication and assembly process of traditional planar metal meander-lines (MLs) structures, by employing an attenuator to support the ML on the bottom of the enclosure rather than welding them together on the sides. To reduce the surface roughness of the molybdenum ML caused by laser cutting, the ML is coated by a thin copper film by magnetron sputtering. The measured S11 of the ML is below −20 dB and S21 varies around −8 dB to −12 dB without the attenuator, while below −40 dB with the attenuator. Particle-in-cell (PIC) simulation results show that with a 4.4-kV, 200-mA sheet electron beam, a maximum output power of 126 W is obtained at 38 GHz, corresponding to a gain of 24.1 dB and an electronic efficiency of 14.3%, respectively.

As a novel composite processing technology, water guided laser has the advantages of small heat affected zone, good surface quality of the cut surface, strong processing depth capability and small taper compared with the traditional dry laser processing technology. In this paper, the infrared water guided laser processing technology is used to process 7075 aluminum alloy, which has high strength, high toughness and corrosion resistance and is widely used in the fields of aerospace, mechanical equipment. The processing parameters of the infrared water guided laser including the effect of 7075 aluminum alloy on the cutting depth, kerf width and surface quality at different feed speed, number of cutting times and peak power are analyzed to extend the processing method of 7075 aluminum alloy. The distance-power curve was also derived based on the fact that the further the power meter was from the nozzle, the lower the power measured within the water column. The experimental results show that the faster the 7075 aluminum alloy feed speed is, the shallower the cutting depth and the smaller the kerf width is, while the higher the number of cuts and the higher the peak power are, both will result in large cutting depth and kerf width. Finally, high quality cutting through and punching of 3mm aluminum alloy plate is achieved, which provides the theoretical basis for the study to infrared water guided laser.

An intelligent laser machining system is developed for precision processing of superhard materials, such as diamond, silicon carbide, silicon nitride, cubic boron nitride, etc. Multiple processing functions, such as laser cutting, laser engraving, laser cleaning and polishing, can be realized by automatically adjusting laser beam parameters. The laser wavelength is 532 nm that is obtained by the second-harmonic generation of a diode-pumped solid-state laser at 1064 nm. The processing system is highly intelligent and automated, from surface scanning and measurement to self-adjustment of laser beam parameters and motion control variables during processing. In our processing, the workpiece is first scanned using a laser sensor and a 3-D profile of the workpiece is created for customer evaluation. Then, with operator’s input of processing requirements, an optimal processing procedure is designed in terms of comprehensive consideration of machining efficiency, processing duration, machine cost, surface quality, material loss, etc. Next, the material is flatten to a certain flatness by using a suitable engraving process, followed by polishing to a certain roughness, and finally cut to shaped pieces. In both the procedure design and material processing, an artificial neural network method is used in the optimization and adjustment of laser beam and motion control parameters. In the experiment of silicon carbide processing, >10-mm thick bulk materials can be cut with nearly vertical edges and polished with ~0.1 um roughness of surface. The system exhibits broad prospects in the processing applications of superhard materials.

Because of the many advantages of high-precision micromachining, picosecond pulsed lasers (PSPLs) can be used to process chemical-vapor-deposited diamonds (CVD-D). With the appropriate PSPL manufacturing technique, sharp and smooth edges of CVD-D micro tools can be generated. In this study, a PSPL is used to cut CVD-D. To optimize PSPL cutting, the effects of its parameters including fluence, pulse pitch, and wavelength on the cutting results were investigated. The results showed that the wavelength had the greatest impact on the sharpness of CVD-D. With PSPL cutting, sharp cutting edges, and smooth fabricated surfaces of the CVD-D, micro tools were achieved. Finally, the fabrication of CVD-D micro milling tools and micro milling experiments were also demonstrated.