Industrial Laser Applications Research Articles

Field laser applications in industry and research

Field laser applications in industry and research

Processing of Highly Reflective Materials

AbstractFiber lasers have become more accepted for industrial laser applications all around the world. For many years, companies and universities have developed new generations of fiber lasers which compete with other laser types such as CO2 lasers. As the market for CO2 lasers shrinks, the solid‐state laser market expands due to advantages such as higher efficiency, high beam quality and the ability to process highly reflective material such as copper and copper‐alloys. Processing such materials would be difficult with a CO2 laser due to the lower absorption characteristics of these metals at their wavelength, but opens a whole new range of laser applications for fiber lasers.

Effect of Annealing by CO2 Laser on Structural and Optical Properties of CuO Thin Films Prepared by Sol – Gel Method

Laser heat treatment is one of the important industrial applications of laser and being studied at the present time as a substitute for conventional thermal annealing. In this research (CuO) thin films have been deposition on a glass by (Sol - Gel / Spin Coating) technique and annealed by two ways, the first one using a convection oven, where they were annealing with three temperatures (400 °C, 500 °C, 600 °C) for one hour, and the second way using a continuous (CO2) laser with (10.6 μm) wavelength and (10 W) power and three intervals (10 min, 15 min, 20 min), were studied structural and optical properties of membranes prepared by both ways to determine the effect of laser annealing on them, and the results of (XRD) tests showed that these membranes with the structural of multi-crystalline monoclinic type and increase the degree of oven annealing temperature, as well as increasing the duration of the laser annealing lead to increased volumes of granular membranes rates. The results of the (AFM) tests to the topography of the surfaces of the membranes to be of crystalline uniformity and homogeneity superficially good, especially for laser annealed membranes. The results of optical examinations of these membranes showed that they having high permeability, especially in the regions of the visible spectrum and the near-infrared and increased with increase the degree of oven annealing temperature and the duration of laser annealing, and less energy gap of these membranes values with increase the temperature degree of annealing or increase of laser annealing time. In addition to this, the optical properties studied in this research included absorbance, reflectivity, refractive index, coefficients of absorption and extinction, and real and imaginary dielectric constants.

Interaction of laser beams with carbon textile materials

Purpose – The purpose of this paper is to present the results of interaction occurring during the exposition of some specific carbon textile materials obtained in laboratory conditions to beams of various laser types. Design/methodology/approach – Carbon fabric materials – fiber, felt and cloth – obtained from different precursor materials and prepared at various process conditions (oxidized, partially carbonized, carbonized, graphitized), were exposed to pulses of various lasers (Nd3+: YAG, alexandrite, ruby). Findings – Depending on the laser power, plasma and destructive phenomena occurred. In the case of an interaction between a Nd3+: YAG laser beam and specimens of thickness in millimeter range, the authors have estimated the threshold of the energy density for drilling and discussed the possible models of the interaction. Research limitations/implications – The results have implications in the estimations of quality as well as in the improvement of material processing, giving some new light to the changes of mechanical and optical constants of the material, as well as to the changes of carbon groups of the material, which would be useful for different types of modeling. Future research will be in the interaction of laser beams with various textile materials, where the investigation would cover the microstructure changes and the implications on cloth cutting and welding, concerning the damages as well as relief structures, specially renew for fs laser regimes. Originality/value – The area of laser applications in the textile industry is supported by scientific and applicative exploration. However, fewer results are concerned with deep introspection into the microstructure of the damages considering the laser interaction with carbon fiber and other carbon-based textiles.

A unified model to determine the energy partitioning between target and plasma in nanosecond laser ablation of silicon

In semiconductor industry, pulsed nanosecond lasers are widely applied for the separation of silicon wafers. Here, the high intensities employed activate a cascade of complex multi-physical and multi-phase mechanisms, which finally result in the formation of a laser induced plasma, shielding the target from the incoming laser beam. Such induced plasma plume, by preventing the laser to effectively reach the target, reduces the overall efficiency and controllability of the ablation process. Modelling can be a useful tool in the optimization of industrial laser applications, allowing a deeper understanding of the way the laser energy distributes between target and induced plasma. Nevertheless, the highly multi-physical character of laser ablation poses serious challenges on the implementation of the various mechanisms underlying the process within a common modelling framework. A novel strategy is here proposed in order to simulate in a simplified, yet physically consistent way, a typical industrial application as laser ablation of silicon wafers. Reasonable agreement with experimental findings is obtained. Three fundamental mechanisms have been identified as the main factors influencing the accuracy of the numerical predictions: the transition from evaporative to volumetric mass removal occurring at critical temperature, the collisional and radiative processes underlying the initial plasma formation stage and the increased impact of the liquid ejection mechanism when a sub-millimeter laser footprint is used.

Field laser applications in industry and research

Field laser applications in industry and research

The dawn of computer-assisted robotic osteotomy with ytterbium-doped fiber laser

Currently, laser radiation is used routinely in medical applications. For infrared lasers, bone ablation and the healing process have been reported, but no laser systems are established and applied in clinical bone surgery. Furthermore, industrial laser applications utilize computer and robot assistance; medical laser radiations are still mostly conducted manually nowadays. The purpose of this study was to compare the histological appearance of bone ablation and healing response in rabbit radial bone osteotomy created by surgical saw and ytterbium-doped fiber laser controlled by a computer with use of nitrogen surface cooling spray. An Ytterbium (Yb)-doped fiber laser at a wavelength of 1,070 nm was guided by a computer-aided robotic system, with a spot size of 100 μm at a distance of approximately 80 mm from the surface. The output power of the laser was 60 W at the scanning speed of 20 mm/s scan using continuous wave system with nitrogen spray level 0.5 MPa (energy density, 3.8 × 10(4) W/cm(2)). Rabbits radial bone osteotomy was performed by an Yb-doped fiber laser and a surgical saw. Additionally, histological analyses of the osteotomy site were performed on day 0 and day 21. Yb-doped fiber laser osteotomy revealed a remarkable cutting efficiency. There were little signs of tissue damage to the muscle. Lased specimens have shown no delayed healing compared with the saw osteotomies. Computer-assisted robotic osteotomy with Yb-doped fiber laser was able to perform. In rabbit model, laser-induced osteotomy defects, compared to those by surgical saw, exhibited no delayed healing response.

Field laser applications in industry and research

The second international conference on Field Laser Applications in Industry and Research—FLAIR was held from September 6–11, 2009 near Garmisch-Partenkirchen in the Bavarian Alps facing Germany’s highest mountain, the Zugspitze. FLAIR in general presents state-of-the-art lasers, components, software and systems, which are used for diagnostic purposes in applied spectroscopy, stable isotope ratio measurements, environmental research, medicine, life sciences and agriculture, plasma and combustion, atmospheric research and in industrial applications [1]. Poster sessions together with an exhibition provide the platform for information exchange between representatives from research and development laboratories, industry and users. FLAIR 2009 provided overview lectures by international experts emphasizing integrative and multi-disciplinary approaches. FLAIR attracts not only spectroscopists, but also scientists with detailed analytical requirements to solve measurement challenges identified in different research areas, even far away from the field of laser spectroscopy. Stimulating discussions always lead to new ideas, cooperation and projects between scientists, between researchers and industry and in the business to business field. We have maintained the style of the conference and the participants could enjoy a week of tight interaction. The activities of the conference have been distributed among dif-

Welding of high thicknesses using a fibre optic laser up to 30 kW

The industrial applications of high-power fibre optic lasers include welding, 2D and 3D cutting, remote cutting and welding, brazing and surface treatments. The availability of fibre optic lasers with power outputs in excess of 10 kW might allow the development of novel fields of application in the welding of high thickness pieces: shipbuilding and offshore industries, pipe and cable manufacture and other heavy industry sectors. Carrying the beam by fibre optics allows high flexibility, even for the production of very large pieces, such as in the shipbuilding sector. This study describes the laser welding of high thickness pieces using a 30 kW laser and a 200 μm diameter fibre. On the one hand, such lasers allow a weld penetration depth of over 30 mm in a single pass, and very high process speeds for thinner materials on the other. Combining lasers with conventional arc welding techniques (hybrid welding) allows further optimization of weld quality and makes it possible to weld butt joints with a ‘gap’ of up to 1 mm. This paper presents the most recent results from very high-power fibre optic laser welding along with new applications in the manufacturing sector.

Determination of the mid-IR femtosecond surface-damage threshold of germanium

To assess the potential uses of germanium as a nonlinear material in the mid IR we have measured the surface-damage threshold of germanium optical windows using femtosecond pulses at a wavelength of 3.9 μm. By working with a wavelength corresponding to a photon energy of less than half the band-gap energy, free-carrier generation due to one- and two-photon absorption was eliminated. The laser pulses had an energy of 5.5 μJ, a duration of 255 fs, and were focused to a waist size of approximately 100 μm. The multi-shot damage threshold of the germanium windows was estimated to be approximately 94 GW/cm2. The data should be of immediate benefit to industrial laser researchers and applications engineers working in the mid-IR region.

LASER PROCESSING ACTIVITIES IN FINLAND – TECHNOLOGICAL AND EDUCATIONAL VIEW

This paper presents the current situation of laser processing technology in Finland; industrial activities, research and development and education. The Finnish laser processing R&D started in 1985 in Lappeenranta University of Technology. The major portion of industrial laser applications are laser cutting and laser welding has a minor role. In the late 1990’s the number of laser welding applications started to grow and many subcontractors established facilities. Research and education on laser materials processing is concentrated in two universities, Lappeenranta and Tampere Universities of Technology. The main research fields are in laser and hybrid welding, surface treatment, laser welding of plastics, micro laser processing and paper processing. In addition, several Applied Universities and schools have started their education and service for the industry in laser and hybrid laser welding and cutting. The postgraduate educational activities in laser processing in Finland are comprehensive in all levels from laser operators to international laser experts. Finland has been the one of the most active countries in the world in organizing continuing education in laser material processing.DOI: http://dx.doi.org/10.5755/j01.mech.18.5.2691

Cutting of nonmetallic materials using Nd:YAG laser beam

This study deals with Nd:YAG laser cutting nonmetallic materials, which is one of the most important and popular industrial applications of laser. The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed. For approximate cutting depth, a theoretical study is conducted in terms of material property and cutting speed. Results show a nonlinear relation between the cutting depth and input energy. There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s. An extra energy is utilized in the deep cutting. It is inferred that as the laser power increases, cutting depth increases. The experimental outcomes are in good agreement with theoretical results. This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting, scribing, trimming, engraving, and marking nonmetallic materials.

Measurement of group velocity dispersion of solvents using 2-cycle femtosecond pulses: Experiment and theory

Second and third-order dispersion for water, methanol, cyclohexane, carbon tetrachloride, dimethyl sulfoxide, toluene and carbon disulfide are measured with high accuracy and precision in the range of 700-900 nm using two-cycle long femtosecond laser pulses. The ratio between second and third-order dispersion, which is predicted to vary linearly, is experimentally confirmed and this observation is examined theoretically. A method to predict second and third-order dispersion of unknown transparent media with accuracy that is comparable to the best experimental methods is proposed and tested. The information provided is important for applications of ultrafast lasers in science, medicine and industry.

Feasibility Study on Laser Cutting of Phenolic Resin Boards

Laser cutting is the most widely implemented application of lasers in industry. The many advantages of this process stimulate users in industry to cut many different materials, such as wood and wood composites –particleboard, plywood, etc.–, which are being cut with excellent results and productivity. Phenolic resins boards are a new substitute of wood in highly aggressive environments. In the present work we study the feasibility of CO2 lasers to cut phenolic resin boards and assess the potential health hazards of the vapours and residues produced, since its thermal degradation may produce toxic organic vapors.

Field laser applications in industry and research

Field laser applications in industry and research

Accuracy and precision of laser spectrometers for trace gas sensing in the presence of optical fringes and atmospheric turbulence

Spectroscopic techniques are increasingly used for field laser applications in industry and research. Under field conditions complex gas sensors cannot be considered as stable and therefore drift characterization is a key issue to distinguish between sample data and sensor drift. In this paper the history of von Neumann’s two-sample variance and Allan variance stability investigations in the field of frequency metrology and the relationship to wavelet analysis are reviewed. The concept has been used to characterize accuracy and precision of spectroscopic data in the time domain and practical guidelines for the interpretation of σ/τ plots are presented. Two topics relevant for spectroscopic measurements are discussed: First, the optical fringe effect, which is present in any spectrometer, limits the precision and accuracy of spectroscopic measurements by forming time dependent background structures superimposed to the signal under investigation. The two-sample variance is used to characterize optical etalons and long-term drift using σ/τ plots. Second, the short-term instrument stability characteristic in the presence of atmospheric turbulence is discussed. This is important for laser-based gas monitors measuring the turbulent transport of trace gases between the biosphere and the atmosphere using the eddy-covariance technique. It will be shown how the spectral characteristics of turbulence in the Kolmogorov inertial subrange can be identified in the time domain and how the effect of optical fringes can be separated from atmospheric signals.

Yttrium Aluminum Garnet as a Scavenger for Ca and Si

Doped yttrium aluminum garnet, Y3Al5O12 (YAG), has drawn considerable attention for solid-state industrial, medical and scientific laser applications. The crystal optical activity is closely related to the type and amount of doping element. Studies on highly yttrium doped, creep resistant alumina ceramics with Ca and Si contamination have indicated that YAG precipitates in the ceramic had a propensity to allow simultaneous incorporation of Ca and Si impurities on the order of 1 % in their structure. Co-solubility potential for Ca and Si in YAG crystals was investigated through systematic doping and co-doping YAG polycrystals with Ca2+ and/or Si4+. It was shown via X-ray diffraction and electron probe microanalysis techniques, that the ceramic can accommodate more than order of magnitude larger amounts of Ca2+ and Si4+ when incorporated in equal amounts simultaneously than when the dopants are introduced alone. The co-solubility limit for Ca and Si was determined to be between 3 and 4 % of the cation amount in pure YAG. Enhanced co-solubility was discussed in terms of size and charge compensations in the lattice. Co-doping with a suitable element is introduced as a possible way to increase the solubility of useful cations in this ceramic that is the host material for lasers

Tunable infrared laser instruments for airborne atmospheric studies

Tunable infrared laser-based instruments on airborne platforms have provided invaluable contributions to atmospheric studies over the past several decades. This paper presents an overview of some recent studies and developments using this approach that were presented at the 2007 Field Laser Applications in Industry and Research (FLAIR, http://www.inoa.it/flair/) conference in Florence, Italy. The present overview only covers select in situ absorption-based instruments that were presented in the airborne session at this conference. In no case are comprehensive details presented. These details can be found in the numerous references given. Additional approaches based upon cavity-enhanced and photoacoustic measurements, which are also making invaluable contributions in airborne atmospheric studies, are not discussed in this brief overview.

Special Issue: “Field Laser Applications in Industry and Research”

Special Issue: “Field Laser Applications in Industry and Research”

Recent Automotive Applications of Laser Processing in Japan

In the automotive industry laser applications have been expanding from small machined parts of engines and transmissions to larger pressed parts of car body. One reason behind the increase of laser applications in the automotive industry is that the high performance and flexible solid state lasers have been developed. Another reason behind is that laser technology offers the potential to meet new vehicle requirements originating from environmental issues and societal demands, which ordinary processing techniques are unable to satisfy. This paper describes recent laser applications as typical examples of the use of lasers by the Japanese car industry to meet the requirement for lighter vehicles and improved fuel economy, which is one of the most critical vehicle issues facing car companies today.