scholarly journals Pulsed UV Laser Processing of Carbosilane and Silazane Polymers

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 372 ◽  
Author(s):  
Samuel Ligon ◽  
Gurdial Blugan ◽  
Jakob Kuebler
Keyword(s):  
Laser Beam ◽  
Laser Processing ◽  
Scanning Speed ◽  
Inert Atmosphere ◽  
Laser Wavelength ◽  
Uv Laser ◽  
Glass Substrates ◽  
Polymer Precursors ◽  
Laser Systems ◽  
Pre Treatment

Freestanding SiCNO ceramic pieces with sub-mm features were produced by laser crosslinking of carbosilane and silazane polymer precursors followed by pyrolysis in inert atmosphere. Three different pulsed UV laser systems were investigated, and the influence of laser wavelength, operating power and scanning speed were all found to be important. Different photoinitiators were tested for the two lasers operating at 355 nm, while for the 266 nm laser, crosslinking occurred also without photoinitiator. Pre-treatment of glass substrates with fluorinated silanes was found to ease the release of green bodies during solvent development. Polymer crosslinking was observed with all three of the laser systems, as were bubbles, surface charring and in some cases ablation. By focusing the laser beam several millimeters above the surface of the resin, selective polymer crosslinking was observed exclusively.

scholarly journals Fabrication of Hydrophilic Surface on Rigid Gas Permeable Contact Lenses to Enhance the Wettability Using Ultraviolet Laser System

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 394
Author(s):  
Hsin-Yi Tsai ◽  
Yu-Chen Hsieh ◽  
Yu-Hsuan Lin ◽  
Han-Chao Chang ◽  
Yu-Hsiang Tang ◽  
...  
Keyword(s):  
Contact Angle ◽  
Contact Lens ◽  
Oxygen Plasma ◽  
Contact Lenses ◽  
Laser System ◽  
Scanning Speed ◽  
Contact Angle Measurement ◽  
Laser Wavelength ◽  
Angle Measurement ◽  
Uv Laser

The widely used rigid gas permeable (RGP) contact lenses provide higher oxygen permeability and tear exchange rate than do soft contact lenses. However, their wettability warrants improvement to enhance the wearing comfort. This study used UV laser (wavelength = 355 nm) to modify the surface properties of RGP contact lenses with materials of Boston XO® (Bausch & Lomb Incorporated). Briefly, the mesh pattern was fabricated on the RGP contact lens surface by using the laser and smoothed by using oxygen plasma; the enhanced hydrophilic efficiency was analyzed using contact angle measurement. The experiment results indicated that the contact angle of the lens material decreased by approximately 10°–20° when the pitch of mesh pattern was <50 μm under a 500-mm/s scanning speed. The oxygen plasma enhanced surface wettability with a decreased contact angle (40°). The hydrophilic characteristic of the UV laser and oxygen plasma–treated surface was twice that of oxygen plasma–treated and untreated surfaces. In the future, RGP contact lens edges could be treated with UV laser and oxygen plasma to enhance the tear wettability and wearing comfort.

Friction Coefficient of the Coating PG-CP4 Sprayed to 40H13 Steel by Plasma and Processed by Laser

2021 ◽  
Vol 410 ◽  
pp. 482-488
Author(s):  
Valentin V. Morozov ◽  
Vladimir G. Gusev ◽  
Aleksey V. Morozov
Keyword(s):  
Friction Coefficient ◽  
Laser Beam ◽  
Laser Treatment ◽  
Plasma Spraying ◽  
Laser Processing ◽  
Factor Model ◽  
Radiation Power ◽  
Laser Head ◽  
Laser Systems

This article deals with laser treatment of plasma spraying of PG-CP4 powder on steel 40H13. A multi-factor model is obtained that relates the friction coefficient of the coating to the radiation power W, the longitudinal feed of the laser beam Spr, and the distance L from the protective glass of the laser head to the sample’s surface. The model allows you to control the modes of laser processing, in order to reduce the friction coefficient of the coating. The greatest influence on the friction coefficient is exerted by the longitudinal feed Spr of the laser beam, followed by the radiation power W and the distance L. A multi-factor model of the friction coefficient of uncoated 40H13 steel treated under the same conditions as coated 40H13 steel is also established. Comparison of the two variants showed that of all the samples providing reliable adhesion of the coating to the substrate, the greatest reduction in the friction coefficient (by 30.2 %) was achieved at W = 5 kW, Spr = 25 mm/s and L = 85 mm. The results of the research are recommended for use in enterprises that implement the processes of plasma and laser processing of materials, as well as in design organizations that develop modern laser systems.

Energy Efficient Laser Beam Welding of Metals with a Ultra-High Brightness Direct-Diode Laser System

2015 ◽  
Vol 805 ◽  
pp. 162-170 ◽  
Author(s):  
Artur Laukart ◽  
Michael Dobler ◽  
Stefanie Kohl ◽  
Haro Fritsche ◽  
Andreas Grohe ◽  
...  
Keyword(s):  
Power Consumption ◽  
Laser Beam ◽  
Numerical Simulations ◽  
Diode Laser ◽  
Laser Beam Welding ◽  
Laser Wavelength ◽  
Efficient Production ◽  
High Brightness ◽  
Laser Systems ◽  
Conventional Laser

The rising level of automation in the automotive industry also involves the use of more and more machines and with that an increase in power consumption. This requires the employment of more efficient production processes with higher efficiency. Laser beam welding offers the opportunity to substitute conventional laser sources like solid state lasers with ultra-high brightness direct-diode laser systems which have the advantage of less power consumption at a comparable beam quality. However, the absorption of laser radiation on metallic surfaces depends on the wavelength, thus the effect of the direct-diode laser wavelength on the welding process has to be investigated. In our research the effect of the laser wavelength on energy efficiency was studied by means of numerical simulations. Furthermore, experimental investigations were carried out to validate the numerical solutions. Different aluminum alloys and steel materials which are used in the automotive environment were investigated within the experiments. Due to the current lack of direct-diode laser systems with a laser power comparable to conventional laser systems, numerical simulations were also used to analyze these future systems. Thus we were able to assess the increase of efficiency in laser beam welding which will be achievable with future high-power direct-diode laser systems.

scholarly journals Wear of the PG-CP4 coating applied by plasma to 40H13 steel and subjected to laser treatment

2021 ◽  
Vol 2131 (5) ◽  
pp. 052039
Author(s):  
V V Morozov ◽  
V G Gusev ◽  
A V Morozov
Keyword(s):  
Laser Beam ◽  
Laser Processing ◽  
Factor Model ◽  
Radiation Power ◽  
Powder Coating ◽  
Laser Head ◽  
First Case ◽  
Uncoated Steel ◽  
Laser Systems ◽  
The Absolute

Abstract This paper discusses the wear of PG-CP4 powder coating deposited by plasma on 40H13 steel and treated by laser. A multi-factor model was established that relates the absolute wear of the PG-CP4 coating to independent factors of the laser processing process and allows you to reduce the coating wear. The longitudinal feed Spr of the laser beam and distance L from the protective glass of the laser head to the processed surface have the greatest and approximately equal influence on the absolute wear of the coating, and the radiation power W -a minimum influence. The research of 40H13 steel coated (the first option) and uncoated steel (the second option), showed that of all the samples that provide reliable adhesion of the coating to the substrate and the greatest reduction in absolute wear (from 80 to 22 micrometers, by 72.5 %) was achieved in the first case at the mode: W = 3 kW, Spr = 10 mm/s and L = 60 mm. The results of the research are recommended for use in enterprises that implement the processes of plasma and laser processing of materials, as well as in design organizations that develop modern technological laser systems.

scholarly journals REDUCING RISK FACTORS IN THE WORKPLACE OF THE LASER SYSTEM OPERATOR

2019 ◽  
Vol 3 ◽  
pp. 184
Author(s):  
Pāvels Narica ◽  
Inese Martinsone
Keyword(s):  
Risk Factors ◽  
Laser Beam ◽  
Thermal Effects ◽  
Laser Processing ◽  
Laser System ◽  
Production Processes ◽  
System Operator ◽  
Laser Systems ◽  
Harmful Substances

Laser processing of materials takes an increasing place in production processes. Improving the performance, improving the quality of processing is not a complete list of the positive aspects of the introduction of laser processing, but there are a number of points that need to be paid attention to during the operation of laser systems - these are issues related to safety. The following risk factors are specific to laser systems: firstly, the laser beam itself, effects on the organs of vision, direct thermal effects on the skin and tissues, secondly, harmful products resulting from the interaction of the laser beam and the material being processed. Aerosols, smoke and dust have different effects on the human body, especially on the respiratory system and the publication considers the risks associated with the release of harmful products during laser processing and the existing methods for reducing the concentration of harmful substances in the working area with specific examples.

Preparation of CuInGaSe2 Absorber Layer by Nanoparticles-Based Spray Deposition

2004 ◽  
Vol 836 ◽  
Author(s):  
Ki-Hyun Kim ◽  
Young-Gab Chun ◽  
Byung-Ok Park ◽  
Kyung-Hoon Yoon
Keyword(s):  
Spray Deposition ◽  
Soda Lime ◽  
Inert Atmosphere ◽  
Absorber Layer ◽  
Step Motor ◽  
Soda Lime Glass ◽  
Soda Lime Glass Substrate ◽  
Glass Substrates ◽  
Spray System ◽  
Cigs Nanoparticles

ABSTRACTCIGS nanoparticles for the CIGS absorber layer have been synthesized by low temperature colloidal routes. The CIGS absorber layers for solar cells have been prepared by spray deposition of CIGS nanoparticle precursors (∼20 nm) in glove box under inert atmosphere. An automatic air atomizing nozzle spray system with computer controlled X-Y step motor system was used to spray. The nanoparticle precursor CIGS film was deposited onto molybdenum-coated soda-lime glass substrates (2.5 cm × 5.0 cm) heated to 160°C. The film thickness in the range of 2 μm ± 0.3 μm was attained by spraying of 3 mM colloidal over an area of 12.5 cm2. The coalescence between particles was observed in the CIGS absorber layer under post-treatment of over 550 °C. This is related to the reactive sintering among the nanoparticles to reduce surface energy of the particles. The CuxSe thin film, formed on Mo film by evaporation, improved adhesion between CIGS and Mo layers and enhanced the coalescence of the particles in the CIGS layer. These are closely related to the fluxing of Cu2Se phase which has relatively low melting temperature. The CdS buffer layer was deposited on the CIGS/Mo/soda-lime glass substrate by chemical bath deposition. The CIGS nanoparticles-based absorber layers were characterized by using energy dispersive spectroscopy (EDS), x-ray diffraction (XRD) and high-resolution scanning electron microscopy (HRSEM).

Chemically Designed, UV Curable Polycarbosilane Polymers

1992 ◽  
Vol 271 ◽  
Author(s):  
Kevin J. Thorne ◽  
Stephen E. Johnson ◽  
Haixing Zheng ◽  
John D. Mackenzie ◽  
M. F Hawthorne
Keyword(s):  
Molecular Weight ◽  
Inert Atmosphere ◽  
Uv Exposure ◽  
Cross Linking ◽  
Substitution Reactions ◽  
High Solubility ◽  
Chemical Route ◽  
Uv Curable ◽  
Polymer Precursors ◽  
C Nmr

ABSTRACTTo prepare new polycarbosilane polymer precursors with high solubility and the capability of UV cross-linking, commercial polycarbosilane was modified by a chemical route. These modifications involved AlCl3 catalyzed chlorination reactions of polycarbosilane's Si-H bonds. The resultant Si-Cl bonds were substituted by a reaction with sodium acetylyde to form Si-C=CH ligands. These ligands are suitable for controlled, free radical initiated cross-linking of the polycarbosilane polymers. The increase in molecular weight should allow for increased Tg's and the retention of polymer pre-forms. In this report, the chlorination of the polycarbosilane polymer and the substitution reactions of polycarbosilane were examined with IR, 29Si and 13C NMR spectroscopy. In addition, the retention of polymer pre-forms were analyzed after UV exposure and inert atmosphere pyrolysis.

scholarly journals Investigation of High-Depostition-Rate Additive Manufacturing of Ti-6Al-4V via Laser Material Deposition

2021 ◽  
Author(s):  
Rebar Hama-Saleh ◽  
Kerim Yildirim ◽  
Susanne Hemes ◽  
Andreas Weisheit ◽  
Constantin Leon Häfner
Keyword(s):  
Additive Manufacturing ◽  
Hot Forging ◽  
Scanning Speed ◽  
Inert Atmosphere ◽  
High Deposition Rate ◽  
Beam Diameter ◽  
Deposition Rates ◽  
Laser Material ◽  
Aerospace Applications ◽  
Material Deposition

Ti-6Al-4V is the most prominent titanium alloy widely used e.g. for aerospace applications. Conventionally, many Ti-6Al-4V aerospace components are produced by a multi-stage hot forging process followed by subsequent machining which often generates a high amount of scrap. Additive manufacturing (AM), such as powder-based laser material deposition (p-LMD), enables parts to be made with geometric freedom and near-net-shape, but so far lacks high deposition rates. The present study proposes high-deposition-rate laser material deposition manufacturing using a large laser beam diameter and increased scanning speed to achieve deposition rates up to 5 kg/h. As Ti-6Al-4V is prone to oxygen pick-up, the process was performed in an inert atmosphere. We determined suitable process windows for tracks without fusion defects and low porosity and investigated microstructure and hardness.

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