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Comprehensive investigation of surface quality and mechanical properties in CO2 laser drilling of GFRP composites
摘要： The present paper aims to study different laser drilling/cutting parameters including laser intensity, cutting speed, and gas pressure in order to achieve minimum surface roughness (Ra), heat-affected zone (HAZ), taper angle (TA), and maximum tensile strength (TS) of the laser-drilled glass fiber-reinforced plastic (GFRP) laminate. Full factorial design of experiment method and analysis of variance were adopted to investigate the effect of each parameter on the responses, and in addition, the surface roughness and tensile strength were compared with that of conventional drilling. The morphology of the laser-drilled holes was studied through the scanning electron microscopy (SEM). It was found that optimum laser drilling parameters can yield higher tensile strength and lower surface roughness in drilled GFRP laminate compared to the conventional drilling. Moreover, multi-response optimization was carried out on the results in order to obtain maximum tensile strength, minimum HAZ, minimum surface roughness, and minimum taper angle. The results revealed that the laser intensity, cutting speed, and assist gas pressure should be set at 2.04 W/cm2, 8 mm/s, and 4 bar, respectively, to obtain higher tensile strength and surface integrity. The results drawn from this study can be applied to improve the surface quality and mechanical properties of laser drilling of FRP materials especially in aircraft part manufacturing.
关键词： FRP,HAZ,Laser machining,Mechanical properties,Fiber-reinforced polymer composite
更新于2025-09-23 15:23:52
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An experimental study on joining of AISI 304 SS to Cu by Nd-YAG laser welding process
摘要： In this current study, a challenging dissimilar metal combination AISI 304 stainless steel and copper is welded by pulsed wave Nd-YAG laser welding process without use of any filler material, followed by its mechanical as well as metallurgical investigation. Macroscopic as well as microscopic examination of the weld surface and weld bead has been carried out to observe the weld penetration depth and metallurgical behavior inside the weld zone. Weld pool geometry confirms about attainment of full penetration depth in pulsed wave Nd-YAG laser and also describes that the penetration depth is directly proportional pulse energy as (penetration depth7 J = 69%) < (penetration depth14 J = 82%) < (penetration depth21 J = 100%). The formed copper micro-channels suggest that the copper solidifies last and flows inside the weld zone matrix during the solidification. The average width of the heat affected zone (HAZ) and partially melting zone (PMZ) have been found to be 23.0 mm and 6.0 mm on the stainless steel (SS) side respectively. The microhardness (MH) study shows that (MHCopper = 75 HV0.1) < (MHWeld zone = 90–200 HV0.1) < (MHSS = 210 HV0.1).
关键词： PMZ,Copper micro-channels,HAZ,Dissimilar metal,Nd-YAG laser
更新于2025-09-23 15:21:01
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Investigation of hole quality in drilled Ti/CFRP/Ti laminates using CO2 laser
摘要： The machinability of titanium (Ti) and carbon fiber reinforced plastic (CFRP) (Ti/CFRP/Ti) laminates using CO2 laser is presented in this work. The effect of line energy and laser frequency on output responses such as heat affected zone (HAZ), taper angle (TA), metal composite interface (MCI) damage, surface roughness, dross height, and circularity were investigated. Line energy - the most influential parameter - demonstrated a threshold behavior; no drilling was observed below a certain line energy. Scanning acoustic microscopy (SAM), scanning electron microscopy (SEM), micro-computed tomography (μ-CT), and other imaging techniques were used to establish a correlation between laser parameters and CO2 laser machined damage in Ti/CFRP/Ti laminates. The results show that using a higher frequency and lower line energy can significantly improve the hole quality. However, dross free holes with minimum taper can be obtained using higher line energy.
关键词： Surface roughness,Circularity,Micro-hardness,CO2 laser,Dross height,HAZ,Drilling,Ti/CFRP/Ti,MCI damage factor,TA
更新于2025-09-23 15:19:57
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Investigation on the Continuous Wave Mode and the ms Pulse Mode Fiber Laser Drilling Mechanisms of the Carbon Fiber Reinforced Composite
摘要： The near infrared (NIR) laser drilling of a carbon fiber reinforced polymer (CFRP) composite in the continuous wave (CW) mode and the ms pulse mode was investigated by an experiment and a numerical simulation. The relationships between the laser penetrating time, entrance hole diameter, surface heat affected zone (HAZ) width, and material ablation rate and the laser irradiation time and laser peak power densities were obtained from the experiment. For the same average power density of the laser output, 3.5 kW/cm2, it was found that the ms pulse laser mode, which had a higher peak power density, had a higher drilling efficiency. When drilling the same holes, the pulse laser mode, which had the highest peak power density of 49.8 kW/cm2, had the lowest drilling time of 0.23 s and had the smallest surface HAZ width of 0.54 mm. In addition, it was found that the laser penetrating time decreased sharply when the peak power density was higher than 23.4 kW/cm2. After analyzing the internal gas pressure by the numerical simulation, it was considered that a large internal gas pressure appeared, which resulted from polymer pyrolysis, causing a large amount of the mechanical erosion of the composite material to improve the drilling efficiency. Therefore, the ms pulse laser showed its potential and advantage in laser drilling the CFRP composite.
关键词： ms pulse,mechanical erosion,peak power density,surface HAZ,laser drilling
更新于2025-09-23 15:19:57
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Simulation and Experimental Based Analysis of the Laser Beam Welding of DP Steels
摘要： In this paper, heat affected zone characteristics of DP1000 steels was investigated during diode laser beam welding (LBW). A butt-welded joint of specimen in dimension of 300 x 150 mm each (according to EN15614-11:2002) with 1 mm thickness is used for the experimental purpose. The welding thermal cycle and the cooling circumstances in the HAZ was determined by real experiment and the physical simulation. A Gleeble 3500 thermo-physical simulator was used to physically simulate the coarse grain heat affected zone (CGHAZ) on the base material specimens by the utilization of the thermal cycles for t8/5 =2.5 s. The results of the physical simulation were validated by real welding experiments. The properties of the simulated and the real HAZ was examined by optical microscopic, scanning electron microscope and hardness tests.
关键词： Gleeble 3500 physical simulator,t8/5 cooling time,Laser beam welding (LBW),dual phase (DP) steel,Heat affected zone (HAZ) characterization
更新于2025-09-19 17:13:59
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The Effect of Fiber Laser Machining Parameters on Thermal-Affected Zone of Carbon Fiber Reinforced Plastic
摘要： This study describes the effects of machining parameters on the thermal-affected zone (heat-affected zone; HAZ) of carbon fiber reinforced plastic using fiber laser. The HAZ described in this study was defined as the area where only resin was removed. In three experiments, the HAZ area and the removal shape of carbon fiber were investigated. The study revealed that pulsed laser reduces the HAZ more than continuous-wave laser does, but it causes the swelling of the carbon fiber tip. Furthermore, the HAZ decreased as the scan speed increased, even if the number of scans was increased. In addition, it was found that nitrogen could restrain the HAZ and the swelling of carbon fiber.
关键词： HAZ,fiber laser,machining of CFRP
更新于2025-09-16 10:30:52
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Dissipative structure of interaction of laser radiation with construction steel 45
摘要： The article presents the results of a quantitative description of the structure of dissipative structures formed during the interaction of carbon steel 45 with laser radiation, revealing the mechanism of their functioning in a no equilibrium process of interaction of a material with concentrated energy ?ow.
关键词： Heat-affected zone (HAZ),Molten phase zone (MPZ),Solid-phase hardening zone (SPHZ),Microstructures,Tempering zone (TZ)
更新于2025-09-16 10:30:52
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Surface integrity of water jet guided laser machining of CFRP
摘要： Carbon fiber reinforced plastics (CFRP) is now applied widely in various industries because of its excellent properties. Although conventional processing methods, such as milling and abrasive water jet, are the dominating techniques used, laser cutting of CFRP is still attractive owing to the wear-free, contactless and flexible processing. However, the anisotropic material properties of CFRP, the issues related to the heat affected zone (HAZ) and delamination during laser processing, are major obstacles in its application. In order to reduce the heat damage caused by laser, a compound machining method, water jet guided laser technique, was adopted to cut CFRP in this paper. In addition, we make a comparative investigation for conventional laser beam machining and water jet guided laser machining with an identical material. The difference of kerf geometry, HAZ, surface morphology and efficiency was discussed within this research. The experiments showed that the HAZ of water jet guided laser is smaller than conventional laser beam machining, but much less efficient. Water jet guided laser technique is a potential processing method for CFRP if the efficiency is improved.
关键词： CFRP,surface morphology,water jet guided laser,HAZ
更新于2025-09-12 10:27:22
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Optimization of process parameter of Laser beam machining of high strength steels: a review
摘要： Metal cutting forms the basis of industry its relevance among products of everyday life due its high strength application in structural, aviation, aerospace, military, naval purpose etc. Based on recent study it is found that many high strength steel are cut using lasers and it has given exceptional result as compared to other Non conventional machining process it is important to know how the cutting is affecting the material properties and which parameters are responsible for such change. The various parameters and their effects are shown in the given study which is analyzed by different researchers along the course of time. The material and thickness and different optimization techniques by different researchers is also shown.
关键词： Macro structural changes,CO2,Control parameters,laser beam cutting (LBC),Heat Affected Zone (HAZ),Micro
更新于2025-09-12 10:27:22
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Experimental Investigation Of Quality Characteristics In Nd:YAG Laser Drilling Of Stainless Steel (AISI 316)
摘要： Micro-machining of advanced engineering materials such as stainless steels, titanium alloys, nickel alloys, and ceramics is a challenging task due to properties like high strength to weight ratio, toughness, slenderness ratio, and low thermal conductivity. Stainless steel of grade AISI 316 has wide applications in medical science, automobile engineering, aviation, and aerospace industry due to their favourable material properties such as low thermal conductivity, high corrosion resistance, and high strength to weight ratio. Micro-machining of AISI 316 with high aspect ratio is a difficult task due to excessive heat generation, micro- structural changes, and tool breakage. Laser beam machining (LBM) process is a suitable alternative machining process, since it localizes the heat source to control the micro-structural changes. The difficulty arises during laser drilling because of spatter area and heat affected zone (HAZ), which adversely affects the quality of laser drilled holes. The present study attempts to experimentally investigate the effect of laser process parameters such as pulse width, laser energy, pulse frequency, and flushing pressure on the performance measures such as spatter deposition and heat affected zone (HAZ) during drilling operation. To reduce the total number of experimental run and obtain maximum information for the experimental trials, Taguchi L27 has been adopted. Analysis of variance (ANOVA) is performed to identify significant laser parameters influencing both the performance measures. From the study, it is revealed that pulse width is the most significant parameter in the formation of spatter and HAZ. From the results, it is identified that spatter area initially increases with increase in pulse frequency and then decreases for any level of pulse width. As pulse frequency increases, laser power increases resulting in more heat input into the material. This causes increase in vapour pressure inside the laser drilled hole, more material ejection, and increase in spatter area. However, laser supported absorption (LSA) waves developed at higher value of pulse frequency brings about blockage of laser energy from the material surface as an engrossing plasma, which results in reduction of material ejection and reduction in spatter area. It is observed that HAZ increases with increase in pulse width and pulse frequency. It may be due to higher average power of the laser beam, which is directly proportional to pulse width and pulse frequency. Higher the value of pulse width, higher will be the laser thermal energy and higher HAZ.
关键词： Laser Drilling,Nd:YAG Laser,HAZ,Spatter
更新于2025-09-12 10:27:22