The Experts below are selected from a list of 102 Experts worldwide ranked by ideXlab platform

Heilma A. - One of the best experts on this subject based on the ideXlab platform.

  • Laser Welding of Polymer foils with gold nanoparticles as optical absorber
    2011
    Co-Authors: Neube M., Heilma A.
    Abstract:

    Gold nanoparticles were used as absorber material for laser Welding of transparent ethylene tetrafluoroethylene (ETFE) Polymer foils. The gold nanoparticles were deposited by magnetron sputtering and covered with a thin plasma Polymer film to stabilize their mechanical properties. After joining the coated foil with an uncoated ETFE foil, Laser irradiation was performed by a defocused continuous wave diode laser at a wavelength of 808 nm. During the laser irradiation, the gold nanoparticle change their size and shape by coalescence and melting and the Welding seam becomes transparent. Particles size and shape were determined by transmission electron microscopy (TEM) and correlated with the optical spectra. Mechanical tensile tests have shown that the tensile strength of the laser Welding seams are comparable to conventional Welding seams made by thermal contact Welding

  • Cryo-FIB-preparation and cryo-SEM investigation of gold nanolayers used as absorber for laser Welding of Polymer foils
    2010
    Co-Authors: Neube M., Cismak A., Heilma A.
    Abstract:

    The morphology of welded Polymer foils was investigated by Scanning Electron Microscopy (SEM) using Focused Ion Beam (FIB) technology for cross-sectional preparation. Due to the sensitive structure of the coPolymer Ethylene Tetrafluororethylene (ETFE), FIB preparation and SEM investigation were performed at cryo conditions. A gold nanolayer was used as absorber for the laser beam to weld the transparent coPolymer foils. The embedding of the gold nanolayer inside the Welding seam and its influence on the mechanical stability of the Welding seams was demonstrated

Andreas Heilmann - One of the best experts on this subject based on the ideXlab platform.

  • Laser Welding of Polymer Foils with Gold Nanoparticles as Optical Absorber
    Advanced Science Letters, 2011
    Co-Authors: Matthias Neuber, Andreas Heilmann
    Abstract:

    Gold nanoparticles were used as absorber material for laser Welding of transparent ethylene tetrafluoroethylene (ETFE) Polymer foils. The gold nanoparticles were deposited by magnetron sputtering and covered with a thin plasma Polymer film to stabilize their mechanical properties. After joining the coated foil with an uncoated ETFE foil, Laser irradiation was performed by a defocused continuous wave diode laser at a wavelength of 808 nm. During the laser irradiation, the gold nanoparticle change their size and shape by coalescence and melting and the Welding seam becomes transparent. Particles size and shape were determined by transmission electron microscopy (TEM) and correlated with the optical spectra. Mechanical tensile tests have shown that the tensile strength of the laser Welding seams are comparable to conventional Welding seams made by thermal contact Welding

  • Cryo‐FIB‐Preparation and Cryo‐SEM Investigation of Gold Nanolayers Used as Absorber for Laser Welding of Polymer Foils
    Macromolecular Symposia, 2010
    Co-Authors: Matthias Neuber, A. Cismak, Andreas Heilmann
    Abstract:

    The morphology of welded Polymer foils was investigated by Scanning Electron Microscopy (SEM) using Focused Ion Beam (FIB) technology for cross-sectional preparation. Due to the sensitive structure of the coPolymer Ethylene Tetrafluororethylene (ETFE), FIB preparation and SEM investigation were performed at cryo conditions. A gold nanolayer was used as absorber for the laser beam to weld the transparent coPolymer foils. The embedding of the gold nanolayer inside the Welding seam and its influence on the mechanical stability of the Welding seams was demonstrated.

L. Højslet - One of the best experts on this subject based on the ideXlab platform.

  • Micro laser Welding of Polymer microstructures using low power laser diodes
    The International Journal of Advanced Manufacturing Technology, 2007
    Co-Authors: T. Ussing, L. V. Petersen, C. B. Nielsen, B. Helbo, L. Højslet
    Abstract:

    The use of laser Welding for joining micro parts has experienced a substantial increase in popularity during recent years. Specifically translucent microfluidic devices are assembled using laser Welding; however, a major issue is the laser beam size of commercially available laser-Welding equipment and thus the resulting Welding seam size, which may be orders of magnitude larger than microfluidic channels and structures. We have successfully achieved extremely small Welding seams using focussed low-power laser diodes. Commercial laser Welding stations for Polymer assembly will typically operate in the power-region 15–50 Watts. The focussed laser beam will have a size of typically 500 μm × 500 μm and may, depending on optical configuration, be up to several mm^2. The resulting Welding-seam will thus be in the area of 300–600 μm depending on beam energy distribution; additionally the melt will spread to unheated areas due to capillary forces. As microfluidic channels are in 20–100 μm regions, even a very limited amount of stray melt may completely fill a part of a channel and thus render it useless. We have used commercially available “single-die” laser-diodes of optical power 200–500 mW. The beam has been focussed and directed using simple optical installations, resulting in a beam-size in the area of 50 μm × 5 μm full width half maximum (FWHM) We have achieved firm Welding seams of width

  • micro laser Welding of Polymer microstructures using low power laser diodes
    The International Journal of Advanced Manufacturing Technology, 2007
    Co-Authors: T. Ussing, L. V. Petersen, C. B. Nielsen, B. Helbo, L. Højslet
    Abstract:

    The use of laser Welding for joining micro parts has experienced a substantial increase in popularity during recent years. Specifically translucent microfluidic devices are assembled using laser Welding; however, a major issue is the laser beam size of commercially available laser-Welding equipment and thus the resulting Welding seam size, which may be orders of magnitude larger than microfluidic channels and structures. We have successfully achieved extremely small Welding seams using focussed low-power laser diodes. Commercial laser Welding stations for Polymer assembly will typically operate in the power-region 15–50 Watts. The focussed laser beam will have a size of typically 500 μm × 500 μm and may, depending on optical configuration, be up to several mm2. The resulting Welding-seam will thus be in the area of 300–600 μm depending on beam energy distribution; additionally the melt will spread to unheated areas due to capillary forces. As microfluidic channels are in 20–100 μm regions, even a very limited amount of stray melt may completely fill a part of a channel and thus render it useless. We have used commercially available “single-die” laser-diodes of optical power 200–500 mW. The beam has been focussed and directed using simple optical installations, resulting in a beam-size in the area of 50 μm × 5 μm full width half maximum (FWHM) We have achieved firm Welding seams of width <10 μm, with a Welding speed of 15 mm/s and with virtually no noticeable spread of melt.

J. Bunte - One of the best experts on this subject based on the ideXlab platform.

  • Laser transmission Welding of Polymer and wood composites: Material and joint mechanism related studies
    Journal of Laser Applications, 2004
    Co-Authors: Heinz Haferkamp, Alexander Von Busse, Stephan Barcikowski, Andreas Ostendorf, J. Bunte
    Abstract:

    Laser beam transmission Welding is an innovative and promising technology for many industries such as the automotive, electronic, and medical industry. Extension to application of this technology to wood components makes it also interesting for the woodworking and furniture industry. Therefore, several investigations in the field of Welding of fiber reinforced thermoplastic and wood composites with Polymers have been carried out. Focus is given to the determination of the weldability and weld behavior of different thermoplastic and wooden materials in matrices relevant for recent industrial applications. Different laser sources with a variety of wavelengths are examined, e.g., high power diode lasers (810, 940 nm) and Nd Yttritium–aluminum–garnet (YAG) laser systems (1064 nm). New approaches using thermographic methods for an easy and fast evaluation of materials qualification regarding their weldability will also be presented. Different plastic and wood components taking into account properties like filling content are investigated. Results show that the thermographic transmission and heating rate are more or less different for Nd:YAG and diode laser radiation depending on the type of laser-transparent Polymer material, production conditions, and on the presence of pigments and other filling materials. Investigating the absorbing materials, it has been shown clearly that a modification of the carbon content is observable very easily in the thermographic images recorded during the heating period. Since natural fiber composites have strong material inhomogenities and anisotropic structures, special process strategies for their application have been developed and are presented in this article.Laser beam transmission Welding is an innovative and promising technology for many industries such as the automotive, electronic, and medical industry. Extension to application of this technology to wood components makes it also interesting for the woodworking and furniture industry. Therefore, several investigations in the field of Welding of fiber reinforced thermoplastic and wood composites with Polymers have been carried out. Focus is given to the determination of the weldability and weld behavior of different thermoplastic and wooden materials in matrices relevant for recent industrial applications. Different laser sources with a variety of wavelengths are examined, e.g., high power diode lasers (810, 940 nm) and Nd Yttritium–aluminum–garnet (YAG) laser systems (1064 nm). New approaches using thermographic methods for an easy and fast evaluation of materials qualification regarding their weldability will also be presented. Different plastic and wood components taking into account properties like fill...

  • Welding of Polymer and wood composites using laser radiation
    International Congress on Applications of Lasers & Electro-Optics, 2003
    Co-Authors: Heinz Haferkamp, Alexander Von Busse, Stephan Barcikowski, J. Bunte
    Abstract:

    Laser beam transmission Welding is an innovative and promising technology for many industries as the automotive, electronic and medical industry. Extension to application of this technology to wood components makes it also interesting for the woodworking and furniture industry. Therefore, the Laser Zentrum Hannover e.V. (LZH) has carried out several investigations in the field of Welding of fiber reinforced thermoplastic and wood composites with Polymers. Focus is given to the determination of the weldability and weld behavior of different thermoplastic and wooden materials in matrices relevant for recent industrial applications. At the LZH, laser beam sources at different wavelengths are examined, e.g. high power diode laser (810 nm, 940 nm) and Nd:YAG laser systems (1064 nm). New approaches using thermographic methods for an easy and fast evaluation of materials qualification regarding their weldability will also be presented. Different plastic and wood components taking into account properties like fil...

Liu Hong-b - One of the best experts on this subject based on the ideXlab platform.

  • ADVANCES IN RESISTANCE Welding of ADVANCED Polymer MATRIX COMPOSITES
    2015
    Co-Authors: Liu Hong-b
    Abstract:

    Due to the superior strength- and stiffness-to-weight ratios and high fatigue resistance,Polymer matrix composites are widely used in various industrial fields,fusion bonding technology of Polymer matrix composites have been a focus of the research. This paper presents an extensive overview of resistance Welding of Polymer matrix composites,discusses the process parameters which affect Welding process and the temperature distribution. Finally,the paper reviews the realization of resistance Welding of thermosetting resin matrix composites and establishment of FEM for resistance Welding of Polymer matrix composites,and expectations on the future development of resistance Welding are put forward.