The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Viboon Tangwarodomnukun - One of the best experts on this subject based on the ideXlab platform.
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Laser ablation of silicon in water at different temperatures
The International Journal of Advanced Manufacturing Technology, 2020Co-Authors: Wisan Charee, Viboon TangwarodomnukunAbstract: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.
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Laser MicroMachining of Titanium Alloy in Water with Different Temperatures
Key Engineering Materials, 2018Co-Authors: Taweeporn Wuttisarn, Viboon Tangwarodomnukun, Chaiya DumkumAbstract:Underwater Laser Machining Process has been employed as an alternative Process to ablate materials with minimum thermal damage. Though many studies provide comprehensive investigations to enable the understanding of Laser-water-material interactions during the Laser ablation Process in water, the effect of water temperature on the ablation performance has not been revealed yet. To cope with this challenge, this paper presents the roles of water temperature on cut dimensions in the underwater Laser microMachining of titanium alloy (Ti-6Al-4V). The effects of Laser power, traverse speed and number of Laser passes were also examined in this study, where groove width and depth were measured and analyzed. The experimental results showed that a deep cut can be produced by using slow traverse speed with multiple-pass technique. However, using too high Laser power can cause a shallow cut due to the large formation of recast in the Laser-ablated area. According to the findings of this study, the Laser energy density of about 750 J/mm2can provide the deepest cut among the other conditions examined in this study.
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Experiment and analytical model of Laser milling Process in soluble oil
The International Journal of Advanced Manufacturing Technology, 2018Co-Authors: Viboon Tangwarodomnukun, Chaiya DumkumAbstract:The liquid-assisted Laser Machining Process is a promising method to cut materials with minimum thermal damage caused by Laser, and water is typically used in the Process due to its high thermal conductivity, nontoxicity, and relatively low price. However, water can intrinsically oxidize ferrous metals and in turn deteriorate the workpiece through corrosion during Laser ablation in water. This study has for the first time proposed Laser ablation in soluble oil to effectively cut the ferrous metals by using Laser in a high cooling rate and low potentiality of corrosion to the metals. A nanosecond pulse Laser was used to scan over the AISI H13 steel sheet to create a square cavity, while the workpiece surface was covered by a thin and flowing soluble oil film throughout the Laser milling Process. The effects of Laser scan overlap, traverse speed, and liquid flow rate on cavity dimensions and milled surface morphology were experimentally examined. The results revealed that a clean and uniform cavity with a smooth machined surface can be attained by using 70% scan overlap, 6 mm/s traverse speed, and 3.9 cm^3/s soluble oil flow rate. Furthermore, analytical models based on heat transfer equations were formulated to predict the cavity profile and cooling of molten droplets in flowing liquid. The predicted profile was found to correspond well to the experiment, and the calculated temperature of cut particles can endorse the experimental findings on debris deposition and recast formation. The implications of this study could bring a new technological approach for damage-free fabrication and fine-scale manufacturing.
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Evolution of milled cavity in the multiple Laser scans of titanium alloy under a flowing water layer
The International Journal of Advanced Manufacturing Technology, 2017Co-Authors: Viboon Tangwarodomnukun, Taweeporn WuttisarnAbstract:The needs for damage-free and fine-scale features with good surface finish have been challenging today’s manufacturing technologies. Laser Machining Process performed under a flowing water layer is a capable technique to satisfy these requirements with high Processing rate and clean cut surface. However, the capability and performance of this Process for milling applications have not clearly been understood yet. Therefore, this study aims at enabling an insight into the Laser milling Process under a flowing water layer. Titanium alloy (Ti-6Al-4V) was employed as a work sample in this study, and a nanosecond pulse Laser was used to ablate the material in water. The effects of Laser traverse speed and number of scans on geometrical dimensions, surface and subsurface characteristics were experimentally investigated. The results revealed that a deeper milled cavity with a smaller taper angle was achievable by using a slower traverse speed and more number of Laser scans. A trade-off between the uniformity and roughness of milled surface was also evidenced under the different Laser traverse speeds examined in this study. By comparing to the Laser milling of titanium alloy in ambient air, there was no metallurgical change remarkably found in the Laser-milled area when the Process was carried out in water. In addition, specific energy required to fabricate a Laser-milled cavity was about 18 kWs/mm^3 for a single scan technique and linearly increased with the number of scans. The findings of this study will advance the understanding of Laser ablation in flowing water as well as other liquid-assisted Laser Machining techniques. The implication of this study will further open wider applications of liquid-assisted Laser ablation for a more intricate micro-fabrication with high resolution, high Processing rate, and less thermal damage.
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Overflow-assisted Laser Machining of titanium alloy: surface characteristics and temperature field modeling
The International Journal of Advanced Manufacturing Technology, 2017Co-Authors: Viboon TangwarodomnukunAbstract:Underwater Laser Machining Process is a promising method to cut materials with less thermal damage. A variation of underwater technique is overflow-assisted Laser ablation. This Process can introduce a higher thermal convection and more uniform water layer than the typical underwater method. Such characteristics can encourage the damage-free fabrication and also stabilize the Laser ablation in water. In this study, cut profile and temperature distribution of workpiece induced by the overflow technique were investigated. Titanium alloy (Ti-6Al-4V) used as a work sample was grooved by a nanosecond pulse Laser under different overflow conditions. The effects of Laser power, Laser repetition rate, and water flow velocity were experimentally and numerically examined. A clean and smooth cut surface can be fabricated when the overflow technique was used. Microcracks and porosities found on the Laser-ablated area were also addressed in this study. The temperature field of titanium alloy under the different ablation conditions was simulated by using the finite difference computation. The transient heat conduction model was implemented together with the enthalpy method and temperature-dependent material properties. By using the developed model, the groove depths obtained from the experiment and simulation were in a good agreement.
Chaiya Dumkum - One of the best experts on this subject based on the ideXlab platform.
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Laser MicroMachining of Titanium Alloy in Water with Different Temperatures
Key Engineering Materials, 2018Co-Authors: Taweeporn Wuttisarn, Viboon Tangwarodomnukun, Chaiya DumkumAbstract:Underwater Laser Machining Process has been employed as an alternative Process to ablate materials with minimum thermal damage. Though many studies provide comprehensive investigations to enable the understanding of Laser-water-material interactions during the Laser ablation Process in water, the effect of water temperature on the ablation performance has not been revealed yet. To cope with this challenge, this paper presents the roles of water temperature on cut dimensions in the underwater Laser microMachining of titanium alloy (Ti-6Al-4V). The effects of Laser power, traverse speed and number of Laser passes were also examined in this study, where groove width and depth were measured and analyzed. The experimental results showed that a deep cut can be produced by using slow traverse speed with multiple-pass technique. However, using too high Laser power can cause a shallow cut due to the large formation of recast in the Laser-ablated area. According to the findings of this study, the Laser energy density of about 750 J/mm2can provide the deepest cut among the other conditions examined in this study.
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Experiment and analytical model of Laser milling Process in soluble oil
The International Journal of Advanced Manufacturing Technology, 2018Co-Authors: Viboon Tangwarodomnukun, Chaiya DumkumAbstract:The liquid-assisted Laser Machining Process is a promising method to cut materials with minimum thermal damage caused by Laser, and water is typically used in the Process due to its high thermal conductivity, nontoxicity, and relatively low price. However, water can intrinsically oxidize ferrous metals and in turn deteriorate the workpiece through corrosion during Laser ablation in water. This study has for the first time proposed Laser ablation in soluble oil to effectively cut the ferrous metals by using Laser in a high cooling rate and low potentiality of corrosion to the metals. A nanosecond pulse Laser was used to scan over the AISI H13 steel sheet to create a square cavity, while the workpiece surface was covered by a thin and flowing soluble oil film throughout the Laser milling Process. The effects of Laser scan overlap, traverse speed, and liquid flow rate on cavity dimensions and milled surface morphology were experimentally examined. The results revealed that a clean and uniform cavity with a smooth machined surface can be attained by using 70% scan overlap, 6 mm/s traverse speed, and 3.9 cm^3/s soluble oil flow rate. Furthermore, analytical models based on heat transfer equations were formulated to predict the cavity profile and cooling of molten droplets in flowing liquid. The predicted profile was found to correspond well to the experiment, and the calculated temperature of cut particles can endorse the experimental findings on debris deposition and recast formation. The implications of this study could bring a new technological approach for damage-free fabrication and fine-scale manufacturing.
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Bubble Formation in the Underwater Laser Ablation of Silicon
Applied Mechanics and Materials, 2016Co-Authors: Wisan Charee, Viboon Tangwarodomnukun, Chaiya DumkumAbstract:Thermal damage of workpiece material induced by Laser Machining Process can be reduced by using the underwater technique. This method requies the whole workpiece to be submerged in water while a Laser beam strikes the work surface for ablation. Though water can cool the workpiece during the ablation, the dynamic features of water can adversely interfere the Laser beam. The vapor bubbles created in water can scatter the Laser beam and in turn attenuate the Laser intensity at the work surface so as the ablation performance. In this paper, the bubble formation caused by Laser Machining of silicon in water was investigated and analyzed. The shadowgraph technique associated with the high speed camera was used to capture and measure the vapor bubble in water. The bubble size was found to increase with the Laser pulse energy. After a number of Laser pulses irradiated on the workpiece surface, the bubble was broken up into small ones which can significantly disturb the Laser beam so as the ablation performance.
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Laser micro milling under a thin and flowing water layer a new concept of liquid assisted Laser Machining Process
Proceedings of the Institution of Mechanical Engineers Part B: Journal of Engineering Manufacture, 2016Co-Authors: Taweeporn Wuttisarn, Viboon Tangwarodomnukun, Chaiya DumkumAbstract:This study proposes a new Laser micro-milling technique for minimizing the thermal damage and gaining a higher material removal rate than using the Laser alone. A low-pressure waterjet was used to ...
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Development of an Overflow-Assisted Underwater Laser Ablation
Materials and Manufacturing Processes, 2014Co-Authors: Soontaree Duangwas, Viboon Tangwarodomnukun, Chaiya DumkumAbstract:Liquid-assisted Laser Machining Processes are of significance in the thermal damage reduction of cut material. However, the Processes suffer the poor cut quality due to the disturbance of water to the Laser beam. This article firstly proposes a new technique to remedy problems found in the general underwater Laser ablation method. An overflow system was incorporated in the Laser Machining Process for introducing a uniform water layer with a steady flow on the workpiece surface. By implementing this new technique, a better cut surface quality than that obtained from dry and typical underwater Laser approaches can be accomplished. It is apparent that this technique could make the normal pulse infrared Lasers feasible for Processing materials with low thermal damage.
Michael F. Modest - One of the best experts on this subject based on the ideXlab platform.
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Energy requirements for ablation or decomposition of ceramics during CO2 and Nd:YAG Laser Machining
Journal of Laser Applications, 1998Co-Authors: Z. Zhang, Michael F. ModestAbstract:In order to assess a priori the outcome of a Laser Machining Process using either simplistic ad hoc or sophisticated models, knowledge is needed of the energy required to remove a unit mass of material. Since Laser–material interactions involve vaporization, decomposition, ejection of fragments, plasma initiation, expansion, etc., extrapolating enthalpy data from JANAF tables will result in significant uncertainty. In this article, an experimental setup to measure this “heat of removal” is described. The apparatus mainly consists of an integrating sphere for the sample and a second integrating sphere for reference. The specimen is mounted at the center of the sample sphere, and is heated by a CO2 or Nd:YAG Laser, whose beam is split, with a part of the beam going into the reference sphere, to monitor the temporal Laser power. The energy reflected by the specimen inside the sample sphere is recorded by a second detector. Combining these data, the total absorbed energy may be deduced. For this type of measu...
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Temperature-Dependent Absorptances of Ceramics for Nd:YAG and CO2 Laser Processing Applications
Journal of Heat Transfer, 1998Co-Authors: Z. Zhang, Michael F. ModestAbstract:The absorptance of a material at the Laser wavelength and as a function of temperature, ranging from room temperature to the removal point, significantly affects the efficiency of the Laser Machining Process. A priori predictions of a Laser Machining Process, using either simplistic or sophisticated models, require knowledge of the material's absorptance behavior. An experimental apparatus for such measurements is described. The device consists of a specimen mounted inside an integrating sphere, heated rapidly by a CO2 or a Nd:YAG Laser. Reflectances are measured with a small focused probe Laser (Nd:YAG or CO2), while specimen surface temperatures are recorded by a high-speed pyrometer. Experimental results have been obtained for wavelengths of 1.06 μm (Nd:YAG) and 10.6 μm (CO2) for graphite, alumina, hot-pressed silicon nitride, sintered α-silicon carbide, as well as two continous-fiber ceramic matrix composites (SiC-based). Data are presented for temperatures between room temperature and the ablation/decomposition points.
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Energy requirements for ablation or decomposition of ceramics during CO2 and Nd:YAG Laser Machining
International Congress on Applications of Lasers & Electro-Optics, 1997Co-Authors: Z. Zhang, Michael F. ModestAbstract:In order to asses a priori the outcome of a Laser Machining Process using either simplistic ad hoc or sophisticated models, knowledge is needed ofthe energy required to remove a unit mass of material. Since Laser-material interactions involve vaporization, decomposition, ejection of fragments, plasma initiation and expansion, etc., extrapolating enthalpy data from JANAF tables will result in significant uncertainty. In this paper, an experimental setup to measure this “heat of removal” is described.The apparatus mainly consists of an integrating sphere for the sample and a second integrating sphere for reference. The specimen is mounted at the center of the sample sphere, and is heated by a CO2 or Nd:YAG Laser, whose beam is split, with a part of the beam going into the reference sphere, to monitor the temporal Laser power. The energy reflected by the specimen inside the sample sphere is recorded by a second detector. Combining these data, the total absorbed energy may be deduced.For this type of measurement, energy losses by convection and radiation are generally negligible, while conduction losses may be substantial. In order to minimize conduction losses, the specimens are manufactured to a thickness of less than 500μm. Still, conduction losses may account for up to 10-20 percent of the total Laser energy for CW and conventionally pulsed Lasers even for such thin samples. Thus, a numerical model is also employed to estimate the conduction losses and to correct the measured value of the “heat of removal.”Experimental data have been obtained for CO2 and Nd:YAG Laser irradiation on graphite, hot-pressed silicon nitride and sintered α-silicon carbide.In order to asses a priori the outcome of a Laser Machining Process using either simplistic ad hoc or sophisticated models, knowledge is needed ofthe energy required to remove a unit mass of material. Since Laser-material interactions involve vaporization, decomposition, ejection of fragments, plasma initiation and expansion, etc., extrapolating enthalpy data from JANAF tables will result in significant uncertainty. In this paper, an experimental setup to measure this “heat of removal” is described.The apparatus mainly consists of an integrating sphere for the sample and a second integrating sphere for reference. The specimen is mounted at the center of the sample sphere, and is heated by a CO2 or Nd:YAG Laser, whose beam is split, with a part of the beam going into the reference sphere, to monitor the temporal Laser power. The energy reflected by the specimen inside the sample sphere is recorded by a second detector. Combining these data, the total absorbed energy may be deduced.For this type of measurem...
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Temperature-dependent absorptances of ceramics for Nd:YAG and CO2 Laser Processing applications
International Congress on Applications of Lasers & Electro-Optics, 1996Co-Authors: Z. Zhang, Michael F. ModestAbstract:The absorptance of a material at the Laser wavelength and as a function of temperature, ranging from room temperature to the removal point, significantly affects the efficiency of the Laser Machining Process. A priori predictions of a Laser Machining Process, using either simplistic or sophisticated models, requires knowledge of the material’s absorptance behavior. An experimental apparatus for such measurements is described. The device consists of a specimen mounted inside an integrating sphere, heated rapidly by a CO2 or a Nd:YAG Laser. Reflectances are measured with a small focused probe Laser (Nd: YAG or CO2), while specimen surface temperatures are recorded by a high-speed pyrometer. Experimental results have been obtained for wavelengths of 1.06μm (Nd:YAG) and 10.6μm (CO2) for graphite, alumina, hot-pressed silicon nitride, sintered α-silicon carbide, as well as two continous-fiber ceramic matrix composites (SiC-based). Data are presented for temperatures between room temperature and the ablation/decomposition points.The absorptance of a material at the Laser wavelength and as a function of temperature, ranging from room temperature to the removal point, significantly affects the efficiency of the Laser Machining Process. A priori predictions of a Laser Machining Process, using either simplistic or sophisticated models, requires knowledge of the material’s absorptance behavior. An experimental apparatus for such measurements is described. The device consists of a specimen mounted inside an integrating sphere, heated rapidly by a CO2 or a Nd:YAG Laser. Reflectances are measured with a small focused probe Laser (Nd: YAG or CO2), while specimen surface temperatures are recorded by a high-speed pyrometer. Experimental results have been obtained for wavelengths of 1.06μm (Nd:YAG) and 10.6μm (CO2) for graphite, alumina, hot-pressed silicon nitride, sintered α-silicon carbide, as well as two continous-fiber ceramic matrix composites (SiC-based). Data are presented for temperatures between room temperature and the ablation/de...
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Measurement of temperature and absorptance for Laser Processing applications
Journal of Laser Applications, 1994Co-Authors: S. Ramanathan, Michael F. ModestAbstract:The use of CO2 Lasers has been successfully demonstrated for several manufacturing Processes such as cutting, drilling, scribing, etc., of a wide range of materials. The absorptance of a material at the Laser wavelength and at the material removal temperature substantially affect the efficiency of the Laser Machining Process. Some materials have absorption bands in the mid‐infrared and the absorptance changes drastically with temperature at the CO2 Laser wavelength of 10.6 μm. Additionally, the absorptance of a material can change due to high‐temperature effects such as decomposition, oxidation, etc., necessitating the measurement of absorptance at temperatures close to the material removal temperature and, preferably, during the Laser Machining Process. A relatively simple experimental set‐up is presented for the measurement of material removal temperature and of the absorptance of ceramic materials at the CO2 Laser wavelength and at temperatures close to the material removal temperature. Experimental re...
Peter Balling - One of the best experts on this subject based on the ideXlab platform.
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Laser structuring of metal surfaces: Micro-mechanical interlocking
Applied Surface Science, 2009Co-Authors: J. Byskov-nielsen, Peter BallingAbstract:Efficient micro-mechanical interlocking may be achieved on appropriately Laser-structured surfaces. In this paper, we discuss the issues relevant for the Laser-Machining Process, including the precision and the material removal rate. We investigate the surface morphology of stainless steel after irradiation by nanosecond Laser pulses at different pulse energies and irradiation strategies. At the optimum operation parameters, we demonstrate that a high-average-power nanosecond Laser provides a reasonable compromise between precision and production time.
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Laser structuring of metal surfaces: Micro-mechanical interlocking
Applied Surface Science, 2009Co-Authors: J. Byskov-nielsen, Peter BallingAbstract:Efficient micro-mechanical interlocking may be achieved on appropriately Laser-structured surfaces. In this paper, we discuss the issues relevant for the Laser-Machining Process, including the precision and the material removal rate. We investigate the surface morphology of stainless steel after irradiation by nanosecond Laser pulses at different pulse energies and irradiation strategies. At the optimum operation parameters, we demonstrate that a high-average-power nanosecond Laser provides a reasonable compromise between precision and production time. © 2008 Elsevier B.V. All rights reserved.
J. Byskov-nielsen - One of the best experts on this subject based on the ideXlab platform.
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Laser structuring of metal surfaces: Micro-mechanical interlocking
Applied Surface Science, 2009Co-Authors: J. Byskov-nielsen, Peter BallingAbstract:Efficient micro-mechanical interlocking may be achieved on appropriately Laser-structured surfaces. In this paper, we discuss the issues relevant for the Laser-Machining Process, including the precision and the material removal rate. We investigate the surface morphology of stainless steel after irradiation by nanosecond Laser pulses at different pulse energies and irradiation strategies. At the optimum operation parameters, we demonstrate that a high-average-power nanosecond Laser provides a reasonable compromise between precision and production time.
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Laser structuring of metal surfaces: Micro-mechanical interlocking
Applied Surface Science, 2009Co-Authors: J. Byskov-nielsen, Peter BallingAbstract:Efficient micro-mechanical interlocking may be achieved on appropriately Laser-structured surfaces. In this paper, we discuss the issues relevant for the Laser-Machining Process, including the precision and the material removal rate. We investigate the surface morphology of stainless steel after irradiation by nanosecond Laser pulses at different pulse energies and irradiation strategies. At the optimum operation parameters, we demonstrate that a high-average-power nanosecond Laser provides a reasonable compromise between precision and production time. © 2008 Elsevier B.V. All rights reserved.
