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Horst Exner - One of the best experts on this subject based on the ideXlab platform.
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Laser Micro melting
International Congress on Applications of Lasers & Electro-Optics, 2015Co-Authors: Andre Streek, Horst ExnerAbstract:Additive manufacturing (AM) offers a quick and efficient method for prototyping and small batch production with a short delivery time or even individual parts. Components of high geometrical complexity can be directly shaped from metals, metal-alloys, metal-matrix composites and from ceramic materials. By a suitable choice of the process parameters AM produced components can meet the demanding requirements of the aerospace, automotive and biomedical industries. Laser Micro sintering (LMS) as a further development of selective Laser sintering uses fine grained powders below 10 µm to produce high accuracy 3D structures (
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Laser Micro sintering of SiO2 with an NIR-Laser
2008Co-Authors: Andre Streek, Peter Regenfuss, Robby Ebert, Tino Süß, Horst ExnerAbstract:Many materials have already been investigated for Laser Micro sintering. Nearly all technical metals can be processed with this rapid prototyping technology. A new field of investigation is the sintering of ceramics. For industrial and also for medical, especially dental, application silicon dioxide is a multiply applicable material. One of its interesting features is that the properties of the resulting material can be varied between ceramic on the one and vitreous on the other side, depending on the extent of crystalline or amorphous character of the nano-scale structure. A special problem with Laser Micro sintering of ceramics is the poor absorption of Nd:YAG Laser radiation by most of the materials. Besides that, Laser Micro sintering of ceramics, in contrary to the process with metals, is not merely a series of aggregational transitions. A solution for the Micro part generation of SiO2 is reported. Typical Laser sintering results from this material are presented. Material specific behaviors during Laser Micro sintering are discussed.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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Principles of Laser Micro Sintering
Rapid Prototyping Journal, 2007Co-Authors: Peter Regenfuss, Andre Streek, Lars Hartwig, Sascha Klötzer, Th. Brabant, M. Horn, Robby Ebert, Horst ExnerAbstract:Purpose – The purpose of the paper is the elucidation of certain mechanisms of Laser material processing in general and Laser Micro sintering in particular. One major intention is to emphasize the synergism of the various effects of q‐switched Laser pulses upon metal and ceramic powder material and to point out the non‐equilibrium character of reaction steps.Design/methodology/approach – Recent results and observations, obtained in development of “Laser Micro sintering,” are surveyed and analyzed. By breaking down the overall process into relevant steps and considering their possible kinetics, an approach is made towards interpreting specific phenomena of Laser Micro sintering. Thermodynamics upon heating of the material as well as its photo‐electronic response to the incident radiation are considered.Findings – The findings corroborate a model whereby short pulses of high intensity provide non‐equilibrium pressure conditions at the location of incidence, that allow for the melting of metal powder with an...
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industrial freeform generation of Microtools by Laser Micro sintering
Rapid Prototyping Journal, 2005Co-Authors: Peter Regenfuss, Lars Hartwig, Sascha Klötzer, Th. Brabant, Robby Ebert, Tino Petsch, Horst ExnerAbstract:Purpose – Examples are given for the technical applicability of a novel development of selective Laser sintering called “Laser Micro sintering”.Design/methodology/approach – Together with a specific method to produce powder layers, the controlled application of pulsed radiation for the processing of sub‐μm grained metal powders was exploited to produce Micro‐tools with a heretofore unattained structural resolution.Findings – High resolution Micro bodies are displayed. Instruments could be generated which proved to fulfil their designation as grip bits for Micro manipulators. The Micro‐bodies can be generated detachably from or firmly fixed to the construction substrate. The material of the generated bodies withstands the traction forces when used as an injection mold for polymer casts.Research limitations/implications – Densities and structural resolutions can still be improved especially with a newly updated version of the equipment. Laser Micro sintering of materials, other than metal (e.g. ceramics), h...
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Advancements in Laser Micro Sintering
2005Co-Authors: Andre Streek, Lars Hartwig, Sascha Klötzer, Robby Ebert, A. Maaz, Horst ExnerAbstract:Until recently, the technique of Laser Micro sintering was employed preferentially for the realization of structural features ranging down to 30µm from sub-Micrometer grained powders. Lately, however, it has been increasingly applied to process coarser powders with grain sizes in the dimension of 10µm. Although a reduction of the resolution has to be taken into account - minimal structures are around 60µm ‐ the variety of available feedstock is considerably higher, allowing for the choice of more economic and industrially interesting materials. Additional advantages are: accelerated performance and improved solidity of the products. Sinter results with a nickel-chromium alloy and a stainless steel powder are presented.
Xiaoyan Zeng - One of the best experts on this subject based on the ideXlab platform.
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Laser Micro/nano-fabrication techniques and their applications in electronics
Advances in Laser Materials Processing, 2010Co-Authors: Yu Cao, Xiaoyan Zeng, Z.x. Cai, Jun DuanAbstract:Abstract Laser Micro-fabrication (LMF) techniques have attracted wide interest in the last two decades because of their high precision, mask-less and rapid processing speed and no tool wear. LMF techniques can take three typical forms: (1) subtractive methods, including Laser ablation, etching and precision cutting; (2) additive methods, including Laser induced chemical vapour deposition, Laser induced electro-less deposition, and Laser Micro-cladding; (3) Laser processing associated with the forming of components, Laser Micro-welding, bonding and forming belong to this type. In this chapter the main principle, mechanisms and advances of LMF are reviewed, which will help readers understand the advantages of LMF technologies, and so find their potential industrial applications in electronics and biological fields.
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Direct fabrication of thermosensors by Laser Micro-cladding functional materials
International Congress on Applications of Lasers & Electro-Optics, 2006Co-Authors: Xiaoyan Zeng, Zhigang DaiAbstract:Sensors are very important products for the information society. As one of the most important sensors, thick film thermo sensors are developing towards to smaller sizes, higher integration and higher precision. Comparing with the thick film thermosensors fabricated by silk screen printing, the Laser Micro-cladding technique is more flexible for its direct fabrication without mask in advance. Furthermore, the sensors fabricated by this technique may be more precise with better quality. In this presentation, thick film thermosensors are fabricated on 96%wt Al2O3 ceramic substrate successfully by Laser Micro-cladding electronic paste. The maximum scanning velocity to fabricate the coatings with good quality can reach 70mm/s. The sensors have excellent surface morphologies and narrow widths (minimum 60µm) with TCR 2330 ppm/°C, the answering time 2.3s and linearity tolerance
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Study on thick film resistor and electrode fabricated by Laser Micro-cladding electronic pastes
Surface and Coatings Technology, 2006Co-Authors: Xiaoyan ZengAbstract:Nowadays, electronic devices are required to be smaller, to have a high-density integration and to be of lower cost. In order to meet the developing demands, some new techniques have appeared in recent years. In this paper, a technique named Laser Micro-cladding electronic pastes is used to fabricate the thick film resistor and electrode units on insulator substrates without using a mask. The results demonstrate that the high-quality resistors could be fabricated by Laser Micro-cladding. However, the processing steps are very important since they have significant effects on the surface finish, the extent of diffusion between electrode film and resistor film, and on the reliability of the resistors. Laser Micro-cladding electronic pastes may become a novel technique to fabricate high quality conductive lines (electrodes) and resistors with good properties that will come into industrial application in the future.
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Conductive line preparation on resin surfaces by Laser Micro-cladding conductive pastes
Applied Surface Science, 2004Co-Authors: Jingwei Liu, Xiaoyan ZengAbstract:In this paper, a novel method named Laser Micro-cladding conductive pastes was used to fabricate silver conductive lines or patterns on resin surfaces directly. The effect of Laser power, coating thickness, and the scanning rates on the conductive line widths was studied systematically, and the resistivity of conductive lines and its adhesion strength with the substrates were measured at different conductive silver particle content levels, based on which the composition and processes were optimized to obtain high quality conductive lines that was narrow, homogeneous with high conductivity and adhesion strength. Finally, the mechanism by Laser Micro-cladding conductive pastes was discussed.
B Bhattacharyya - One of the best experts on this subject based on the ideXlab platform.
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Pulsed Nd:YAG Laser Micro-turning Process of Alumina Ceramics
Lasers Based Manufacturing, 2015Co-Authors: Golam Kibria, Biswanath Doloi, B BhattacharyyaAbstract:Laser Micro-turning process is one of the new and emerging technologies in the area of Laser material processing (LMP) of engineering materials. It is employed for generation of Micro-turning surface of particular surface profile and dimensional accuracy on cylindrical workpiece with specific length and depth of turn within tight tolerance. As the process is recently developed Micro manufacturing technique, a well planned research study and experimental investigation should be conducted considering various Laser Micro-turning process parameters. Therefore, various experimental schemes are adapted to study and analysis of significant process parameters on response criteria such as surface roughness and machining depth. A servo controller based fixture is designed and developed indigenously to hold and rotate the cylindrical shaped work samples at various workpiece rotating speed. Overlap between two successive spots (i.e. spot overlap) and overlap between two successive Micro-groove widths (i.e. circumferential overlap) play major role for generating quality surface features during Laser Micro-turning process. Therefore, mathematical formulations of spot overlap and circumferential overlap are developed for better understanding of the Laser Micro-turning process and also to study the effects of these overlap factors on performance characteristics. Moreover, attempt has been made to carry out experimental investigation to Micro-turn cylindrical shaped engineering ceramics at Laser defocus conditions of Laser beam. Moreover, comparative study and analyse is performed to explore the effect of focused and defocused conditions of Laser beam on surface roughness criteria. SEM Micrographs of the Laser turned surface captured at various parametric combinations have also been studied for qualitative analysis of the process.
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Experimental analysis on Nd:YAG Laser Micro-turning of alumina ceramic
The International Journal of Advanced Manufacturing Technology, 2010Co-Authors: Golam Kibria, Biswanath Doloi, B BhattacharyyaAbstract:Laser Micro-turning is a Micro-machining strategy to machine cylindrical workpiece of hard-to-process materials such as ceramics. Laser Micro-turning method is in high demand in the present high-precision manufacturing industries because of its wide and potential uses in various engineering fields such as automobile, electronics, aerospace, and biomedical applications, etc. In the present research, the experimental analysis of Nd:YAG Laser Micro-turning of cylindrical-shaped ceramic material has been made to explore the desired Laser output responses, i.e., depth of cut and surface roughness by varying Laser Micro-turning process parameters such as lamp current, pulse frequency, and Laser beam scanning speed. Single Laser beam has been utilized for successful Micro-turning operation. Experimental results revealed that the Laser machining process parameters have great influences for achieving desired Laser Micro-turned depth and surface roughness characteristics during Laser Micro-turning of alumina ceramics. SEM and optical photographs have also been analyzed for better understanding of the Laser Micro-turning process for different parametric settings.
Golam Kibria - One of the best experts on this subject based on the ideXlab platform.
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Pulsed Nd:YAG Laser Micro-turning Process of Alumina Ceramics
Lasers Based Manufacturing, 2015Co-Authors: Golam Kibria, Biswanath Doloi, B BhattacharyyaAbstract:Laser Micro-turning process is one of the new and emerging technologies in the area of Laser material processing (LMP) of engineering materials. It is employed for generation of Micro-turning surface of particular surface profile and dimensional accuracy on cylindrical workpiece with specific length and depth of turn within tight tolerance. As the process is recently developed Micro manufacturing technique, a well planned research study and experimental investigation should be conducted considering various Laser Micro-turning process parameters. Therefore, various experimental schemes are adapted to study and analysis of significant process parameters on response criteria such as surface roughness and machining depth. A servo controller based fixture is designed and developed indigenously to hold and rotate the cylindrical shaped work samples at various workpiece rotating speed. Overlap between two successive spots (i.e. spot overlap) and overlap between two successive Micro-groove widths (i.e. circumferential overlap) play major role for generating quality surface features during Laser Micro-turning process. Therefore, mathematical formulations of spot overlap and circumferential overlap are developed for better understanding of the Laser Micro-turning process and also to study the effects of these overlap factors on performance characteristics. Moreover, attempt has been made to carry out experimental investigation to Micro-turn cylindrical shaped engineering ceramics at Laser defocus conditions of Laser beam. Moreover, comparative study and analyse is performed to explore the effect of focused and defocused conditions of Laser beam on surface roughness criteria. SEM Micrographs of the Laser turned surface captured at various parametric combinations have also been studied for qualitative analysis of the process.
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Optimization of Surface Roughness during Nd:YAG Laser Micro-Turning Process of Alumina
Journal of the Association of Engineers India, 2014Co-Authors: Golam Kibria, Biswanath Doloi, B. BhattacharyyaAbstract:Laser Micro-turning process is one of the newly developed Laser material processing technologies to generate Micro-turned groove or surface on cylindrical workpiece. In the present paper, an attempt has been made to investigate the Laser Micro-turning operation on cylindrical shaped aluminium oxide (Al 2 O 3 ) ceramic to study the influence of different Laser Micro-turning process parameters namely, Laser average power, pulse frequency, workpiece rotational speed, assist air pressure and Y feed rate using response surface methodology (RSM) experimental plan. The mathematical model for surface roughness (Ra) has been developed and the adequacy of the model has been tested through analysis of variance (ANOVA) results. Average power and pulse frequency are the most significant process parameters. Optimal parametric combination for minimum value of surface roughness has been achieved as 5.23μm at parametric setting of average power of 9.04 W, pulse frequency of 4108.18 Hz, workpiece rotational speed of 451.16 rpm, air pressure of 1.44 kgf/cm 2 and Y feed rate of 0.37 mm/s. Confirmation experimental results show a good agreement between RSM based optimal and experimental value of response criterion.
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Experimental analysis on Nd:YAG Laser Micro-turning of alumina ceramic
The International Journal of Advanced Manufacturing Technology, 2010Co-Authors: Golam Kibria, Biswanath Doloi, B BhattacharyyaAbstract:Laser Micro-turning is a Micro-machining strategy to machine cylindrical workpiece of hard-to-process materials such as ceramics. Laser Micro-turning method is in high demand in the present high-precision manufacturing industries because of its wide and potential uses in various engineering fields such as automobile, electronics, aerospace, and biomedical applications, etc. In the present research, the experimental analysis of Nd:YAG Laser Micro-turning of cylindrical-shaped ceramic material has been made to explore the desired Laser output responses, i.e., depth of cut and surface roughness by varying Laser Micro-turning process parameters such as lamp current, pulse frequency, and Laser beam scanning speed. Single Laser beam has been utilized for successful Micro-turning operation. Experimental results revealed that the Laser machining process parameters have great influences for achieving desired Laser Micro-turned depth and surface roughness characteristics during Laser Micro-turning of alumina ceramics. SEM and optical photographs have also been analyzed for better understanding of the Laser Micro-turning process for different parametric settings.
Peter Regenfuss - One of the best experts on this subject based on the ideXlab platform.
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Laser Micro sintering of SiO2 with an NIR-Laser
2008Co-Authors: Andre Streek, Peter Regenfuss, Robby Ebert, Tino Süß, Horst ExnerAbstract:Many materials have already been investigated for Laser Micro sintering. Nearly all technical metals can be processed with this rapid prototyping technology. A new field of investigation is the sintering of ceramics. For industrial and also for medical, especially dental, application silicon dioxide is a multiply applicable material. One of its interesting features is that the properties of the resulting material can be varied between ceramic on the one and vitreous on the other side, depending on the extent of crystalline or amorphous character of the nano-scale structure. A special problem with Laser Micro sintering of ceramics is the poor absorption of Nd:YAG Laser radiation by most of the materials. Besides that, Laser Micro sintering of ceramics, in contrary to the process with metals, is not merely a series of aggregational transitions. A solution for the Micro part generation of SiO2 is reported. Typical Laser sintering results from this material are presented. Material specific behaviors during Laser Micro sintering are discussed.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
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Principles of Laser Micro Sintering
Rapid Prototyping Journal, 2007Co-Authors: Peter Regenfuss, Andre Streek, Lars Hartwig, Sascha Klötzer, Th. Brabant, M. Horn, Robby Ebert, Horst ExnerAbstract:Purpose – The purpose of the paper is the elucidation of certain mechanisms of Laser material processing in general and Laser Micro sintering in particular. One major intention is to emphasize the synergism of the various effects of q‐switched Laser pulses upon metal and ceramic powder material and to point out the non‐equilibrium character of reaction steps.Design/methodology/approach – Recent results and observations, obtained in development of “Laser Micro sintering,” are surveyed and analyzed. By breaking down the overall process into relevant steps and considering their possible kinetics, an approach is made towards interpreting specific phenomena of Laser Micro sintering. Thermodynamics upon heating of the material as well as its photo‐electronic response to the incident radiation are considered.Findings – The findings corroborate a model whereby short pulses of high intensity provide non‐equilibrium pressure conditions at the location of incidence, that allow for the melting of metal powder with an...
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industrial freeform generation of Microtools by Laser Micro sintering
Rapid Prototyping Journal, 2005Co-Authors: Peter Regenfuss, Lars Hartwig, Sascha Klötzer, Th. Brabant, Robby Ebert, Tino Petsch, Horst ExnerAbstract:Purpose – Examples are given for the technical applicability of a novel development of selective Laser sintering called “Laser Micro sintering”.Design/methodology/approach – Together with a specific method to produce powder layers, the controlled application of pulsed radiation for the processing of sub‐μm grained metal powders was exploited to produce Micro‐tools with a heretofore unattained structural resolution.Findings – High resolution Micro bodies are displayed. Instruments could be generated which proved to fulfil their designation as grip bits for Micro manipulators. The Micro‐bodies can be generated detachably from or firmly fixed to the construction substrate. The material of the generated bodies withstands the traction forces when used as an injection mold for polymer casts.Research limitations/implications – Densities and structural resolutions can still be improved especially with a newly updated version of the equipment. Laser Micro sintering of materials, other than metal (e.g. ceramics), h...
