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Fujii Y.,Toyohashi University of Technology | Imai T.,Toyohashi University of Technology | Miyamoto Y.,Toyohashi University of Technology | Ueda N.,Toyohashi University of Technology | And 10 more authors.
Surface and Coatings Technology | Year: 2016

Tetrahedral amorphous carbon (ta-C) films were prepared on cutters which are used for engraving. Engraving tests were performed on metal plates using non-coated and ta-C-coated cutters, under dry machining conditions, without oil. Generally, the metal plate is engraved using a cemented carbide (WC-Co) cutter, which uses oil for the cutting process, to fabricate a nameplate. The oil causes a high environmental load and complicates the machining process. Therefore, from an industrial viewpoint, there is a need for a dry machining process. The ta-C film is a hydrogen-free diamond-like carbon film with a high mechanical hardness. In this study, droplet-free ta-C films were prepared on WC-Co cutters using a T-shape filtered arc deposition method. The work materials used in the engraving tests were aluminum, copper, and brass. The results of the engraving tests demonstrated suppression of metal adhesion to the cutting edge, prevention of chipping of the cutting edge, and a decrease in cutting resistance during engraving when a ta-C film had been coated onto the cutting edge. In addition, burr and residue on engraved grooves were also suppressed by using a ta-C-coated cutter. The ta-C film coating offered a remarkable improvement in the engraving performance of a WC-Co cutter in the dry machining process. © 2016 Elsevier B.V. Source


Yanagita T.,Toyohashi University of Technology | Tanoue H.,Toyohashi University of Technology | Kamiya M.,Toyohashi University of Technology | Kamiya M.,Itoh Optical Industrial Co. | And 5 more authors.
IEEJ Transactions on Fundamentals and Materials | Year: 2011

Electromagnetically pulled-out gas plasma (EPOP) gun was developed, which will be applied to the filtered arc deposition system in order to enhance the nitriding of preparing thin film under medium vacuum. A hot cathode of tungsten (W) filament was employed and DC discharge was generated between the cathode and anode (SUS304). The distance of electrodes was 100 mm. Electromagnetic coils were placed around the cathode, anode and plasma pulled-out duct, separately. Experimental pressure was 0.1 Pa. The following results were obtained. Ignition voltage became lower when the same direction magnetic field was axially applied to the cathode and anode. Minimum voltage for sustaining the discharge became lower when the magnetic filed was applied to the anode. With increasing discharge voltage, the discharge current increased dramatically for the discharge voltage less than 50 V and increased gradually for the voltage more than that. The plasma between the cathode and anode was able to be pulled out to the process chamber by applying magnetic field perpendicular to the discharge axis. The amount of pulled-out plasma increased with increasing the filament current and magnetic flux density for plasma pulling-out. © 2011 The Institute of Electrical Engineers of Japan. Source


Tanoue H.,Toyohashi University of Technology | Kamiya M.,Toyohashi University of Technology | Kamiya M.,Itoh Optical Industrial Co. | Suda Y.,Toyohashi University of Technology | And 7 more authors.
Japanese Journal of Applied Physics | Year: 2011

Diamond-like carbon (DLC) film is sometimes removed using oxygen plasma in order to reuse workpieces such as cutting tools and press molds. In this study, an oxygen-dominated plasma beam was generated by converting the cathodic carbon arc plasma beam formed in T-shaped filteredarc-deposition (T-FAD) in order to investigate the feasibility of using the plasma beam for the removal of DLC film. When the oxygen (O2) gas flow rate was relatively high (50 ml/min) and the substrate was biased (DC -500 V), the plasma beam in front of the substrate was confirmed to contain a considerable amount of excited oxygen atoms, since an atomic oxygen spectral line (777 nm) emitted from the plasma beam had relatively strong radiation intensity. The plasma beam was irradiated on a tetrahedral amorphous carbon film, a hydrogen-free sp3-rich DLC film, prepared on a hard alloy (WC with 6wt% Co binder) substrate. It was found that a plasma beam generated with an appropriate O2 gas flow rate and applied substrate bias was able to etch the DLC film proportionally to the treatment time. The surface was not roughened when the treatment time was 1.5 times longer than the intended time to remove a given thickness of DLC film. © 2011 The Japan Society of Applied Physics. Source


Tanoue H.,Toyohashi University of Technology | Kamiya M.,Toyohashi University of Technology | Kamiya M.,Itoh Optical Industrial Co. | Oke S.,Toyohashi University of Technology | And 9 more authors.
Thin Solid Films | Year: 2010

Substrate etching by means of Ar-mixed graphite-cathodic-arc plasma beam was investigated in a newly-developed compact-type μT-FAD. The surface level and roughness change were measured as a function of the Ar gas flow rate, when Ar gas was introduced into the arc generation zone and in the vicinity of the substrate. When Ar gas was introduced to the arc generation zone, the etching rate was lower but the surface was relatively not roughened. When Ar gas was introduced in the vicinity of the substrate, the etching rate was higher but the surface was roughened. At the same gas flow rate (and pressure), the substrate was etched more than three times faster when Ar gas was introduced into the arc generation zone than to the vicinity of the substrate. After measuring the discharge and plasma conditions, the results were considered to be caused by the difference in the amount of plasma transported to the substrate. © 2009 Elsevier B.V. All rights reserved. Source


Yasui H.,Industrial Research Institute of Ishikawa | Taki M.,Onward Ceramic Coating Co. | Hasegawa Y.,Onward Ceramic Coating Co. | Takago S.,Industrial Research Institute of Ishikawa
Surface and Coatings Technology | Year: 2011

Because high density DLC (HD-DLC) films prepared using filtered arc deposition (FAD) systems possess high hardness, low friction coefficients, and a smooth surface, they have been good candidates for use in tribological applications. The aim of present work is the investigation of the mechanical and structural properties of HD-DLC films.The experimental conditions were the following: arc current, 50A; base pressure, less than 3×10-3Pa; substrate bias, DC-100V; substrate temperature, less than 100°C. The HD-DLC films were formed on silicon wafers and tungsten carbide (WC) substrates. The film properties of hardness, composition, structure, and friction were analyzed.The film hardness is high, 80?-90. GPa, with a low friction coefficient of less than 0.1. © 2011 Elsevier B.V. Source

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