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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Manufacturing Technology Engineers
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The Korean Society of Manufacturing Technology Engineers
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Volume & Issues
Volume 24, Issue 6 - Dec 2015
Volume 24, Issue 5 - Oct 2015
Volume 24, Issue 4 - Aug 2015
Volume 24, Issue 3 - Jun 2015
Volume 24, Issue 2 - Apr 2015
Volume 24, Issue 1 - Feb 2015
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Thermally Adjusted Graphene Oxide as the Hole Transport Layer for Organic Light-Emitting Diodes
Shin, Seongbeom ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 363~367
DOI : 10.7735/ksmte.2015.24.4.363
This paper reports on thermally adjusted graphene oxide (GO) as the hole transport layer (HTL) for organic light-emitting diodes (OLEDs). GO is generally not suitable for HTL of OLEDs because of intrinsic specific resistance. In this paper, the specific resistance of GO is adjusted by the thermal annealing process. The optimum specific resistance of HTL is found to be
, and is defined by the maximum current efficiency of OLEDs, 2 cd/A. In addition, the reasons for specific resistance change are identified by x-ray photoelectron spectroscopy (XPS). First, the XPS results show that several functional groups of GO were detached by thermal energy, and the amount of epoxide changed substantially following the temperature. Second, the full width at half maximum (FWHM) of the C-C bond decreased during the process. That means the crystallinity of the graphene improved, which is the scientific basis for the change in specific resistance.
Fabrication of Porous Alumina Ceramics Using Hollow Microspheres as the Pore-forming Agent
Nie, Zhengwei ; Lin, Yuyi ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 368~373
DOI : 10.7735/ksmte.2015.24.4.368
Porous alumina ceramics with two different pore sizes were fabricated using hollow microspheres as the pore-forming agent. The relative density, total porosity, and microstructure of the obtained alumina ceramics were studied. It was found that the total porosity of sintered samples with different amounts of hollow microsphere content, from 2.0 to 4.0 wt%, was 69.3-75.6%. The interconnected and spherical cell morphology was obtained with 3.0 wt% hollow microsphere content. The resulting ceramics consist of a hierarchical structure with large-sized cells, and small-sized pores in the cell walls. Moreover, the compressive strength of the sintered samples varied from 8.3-11.5 MPa, corresponding to hollow microsphere contents of 2.0-4.0 wt%.
Improvement of Computer-Aided Manufacturing (CAM) Software for Laser Machining
Bayesteh, Abdoleza ; Ko, Junghyuk ; Ahmad, Farid ; Jun, Martin B.G. ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 374~385
DOI : 10.7735/ksmte.2015.24.4.374
In this paper, effective and user friendly CAM software is presented that automatically generates any three dimensional complex toolpaths according to a CAD drawing. In advanced manufacturing, often it is essential to scan the sample following a complex trajectory which consists of short (few microns) and multidirectional moves. The reported CAM software offers constant velocity for all short trajectory elements and provides an efficient shift of tool path direction in sharp corners of a tool trajectory, which is vital for any laser, based precision machining. The software also provides fast modification of tool path, automatic and efficient sequencing of path elements in a complicated tool trajectory, location of reference point and automatic fixing of geometrical errors in imported drawing exchange files (DXF) or DWG format files.
Development of a Costing Model for Wooden Patterns of Casting Structures for Machine Tools
Seo, Han-Tae ; Choi, Jin-Woo ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 386~393
DOI : 10.7735/ksmte.2015.24.4.386
A study is carried out on investigation on pattern costs, identification of geometric parameters for the cost, and development of cost estimation models for casting patterns. Pattern costs for machine tool structures are collected and analyzed to identify the important geometric parameters that affect the costs. The parameters are used for the development of the costing models. It is found that the geometric parameters can be easily obtained from a CAD system and then the costing models estimate a pattern cost in a minimum time. The models are verified with the structures whose pattern cost was used for this study. It is expected that this costing models can evaluate the cost of casting structures of machine tools in search of a near-optimal design based on manufacturing cost and, for example, weight at the design stage.
Numerical Analysis on Flow Uniformity According to Area Ratio and Diffuser Angle in an SCR Reactor of a 500 PS-Class Ship
Seong, Hongseok ; Park, Inseong ; Jang, Hyun ; Park, Changdae ; Kim, Hyunkyu ; Jung, Kyoungyul ; Suh, Jeongse ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 394~399
DOI : 10.7735/ksmte.2015.24.4.394
Because flow uniformity affects the life cycle and performance of the catalyst, it is an important design factor for selective catalytic reduction (SCR) systems. We examined how the diffuser angle and the area ratio of the inlet of the SCR reactor to the front of the catalyst affect flow uniformity. For the numerical analysis, we used STAR-CCM+, a common CFD software program. Analysis results showed that the larger the area ratio was, the less the flow uniformity was, and that the longer the diffuser length was, the greater the flow uniformity was. When the area ratio was greater than 1:5, the flow uniformity appeared very similar at the front of the catalyst. As a result, the spread time of the exhaust gas increased and the flow velocity decreased.
Structure of a Plasma Ion Source for a Cross-Section SEM Sample
Won, Jong-Han ; Jang, Dong-Young ; Park, Man-Jin ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 400~406
DOI : 10.7735/ksmte.2015.24.4.400
This study researched the structure of the source of an ion milling machine used to fabricate a scanning electron microscope (SEM) sample. An ion source is used to mill out samples of over 1 mm dimension using a broad ion beam to generate plasma between the anode and cathode using a permanent magnet. To mill the sample in the vacuum chamber, the ion source should be greater than 6 kV for a positive ion current over
. To discover the optimum operating conditions for the ion miller, the diameter of the extractor, anode shape, and strength of the permanent magnet were varied in the experiments. A silicon wafer was used as the sample. The sputter yield was measured on the milled surface, which was analyzed using the SEM. The wafer was milled by injecting 1 sccm of argon gas into the 0.5 mTorr vacuum chamber.
Continuous Microalgae Separation Process Using Ultrasonic Waves
Kim, Sung Bok ; Jeong, Sang Hwa ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 407~413
DOI : 10.7735/ksmte.2015.24.4.407
Research for renewable energy is being performed since it has the merits of little pollution of the environment and sustainable energy resources. Microalgae is attractive as a renewable energy resource. Biomass of the microalgae can be produced by mass culturing, and bulk harvest technology of is needed to produce biomass continuously. Recently, ultrasonic waves were used to harvest the cultivated microalgae continuously. In this study, the separation process using ultrasonic waves was performed to effectively harvest the microalgae. An ultrasonic wave separation resonator was designed and manufactured based on the acoustic field analysis. Separation experiments using design of experiment were carried out, and the influence of experimental variables from the ultrasonic wave separation process was investigated. Mixing conditions of variables were estimated to obtain high separation efficiency and a large microalgae harvest. Experimental results for suitable mixing conditions were compared with simulation results calculated from the state equation.
Precise Control of Inchworm Displacement Using the LQG/LTR Technique
Jeon, Yoon-Han ; Hwang, Yun-Sik ; Park, Heung-Seok ; Kim, In-Soo ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 414~420
DOI : 10.7735/ksmte.2015.24.4.414
In this study, the linear quadratic Guassian loop transfer recovery (LQG/LTR) control technique was combined with an integrator and applied to an inchworm having piezoelectric actuators for precise motion tracking. The piezoelectric actuator showed nonlinear response characteristics, including hysteresis, due to its ferroelectric characteristics and the residual displacement phenomenon. This paper proposes a feedback control scheme using the LQG/LTR controller with an integrator to improve the ability to track the response to complex input signals and to suppress the phenomenon of hysteresis and residual vibration. Experimental results show that the developed feedback control system for an inchworm can track the various motion contours quickly without residual vibration or overshoot.
Prediction of Elastic Bending Modulus of Multi-layered Graphene Sheets Using Nanoscale Molecular Mechanics
Kim, Dae-Young ; Han, Seog-Young ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 421~427
DOI : 10.7735/ksmte.2015.24.4.421
In this paper, a description is given of finite element method (FEM) simulations of the elastic bending modulus of multi-layered graphene sheets that were carried out to investigate the mechanical behavior of graphene sheets with different gap thicknesses through molecular mechanics theory. The interaction forces between layers with various gap thicknesses were considered based on the van der Waals interaction. A finite element (FE) model of a multi-layered rectangular graphene sheet was proposed with beam elements representing bonded interactions and spring elements representing non-bonded interactions between layers and between diagonally adjacent atoms. As a result, the average elastic bending modulus was predicted to be 1.13 TPa in the armchair direction and 1.18 TPa in the zigzag direction. The simulation results from this work are comparable to both experimental tests and numerical studies from the literature.
The Fracture Effect of a Non-Symmetric Laser Beam on Glass Cutting
Yoon, Sangwoo ; Kim, Joohan ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 428~433
DOI : 10.7735/ksmte.2015.24.4.428
A non-symmetric laser beam was used for cutting a thin glass substrate and its effect was investigated. In laser cutting of brittle materials, controlling crack initiation on the surface is crucial; however, it is difficult to ensure that crack propagation occurs according to a designed laser path. A lot of deviation in crack propagation, especially at the edge of the substrate, is usually observed. A non-symmetric laser beam generates a non-uniform energy distribution, which enhances directional crack propagation. A 20-W pulsed YAG laser was used for cutting a thin glass substrate. Parametric analysis was carried out and the crack control of the non-symmetric laser beam was improved. A theoretical model was presented and the limitations of the proposed process were also discussed.
Development of a Wireless Telemetry Measurement Algorithm Using Smart Phones and Digital Image Correlation
Choi, In Young ; Kang, Young June ; Hong, Kyung Min ; Kim, Seong Jong ; Lee, Hae Gyu ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 434~440
DOI : 10.7735/ksmte.2015.24.4.434
A smart phone is a multimedia device that is a necessity for modern people. It includes a wireless networking system to share information and pictures. However, numerous smart phones are discarded every year, since they have a very fast technology development cycle. This paper presents the development of a telemetry algorithm to measure displacement and strain with a discarded smart phone and digital image correlation methods. To implement the measurement algorithm, the LabVIEW 2010 program development platform was used. In order to verify reliability, an open hole tension test was conducted using a smart phone and a universal test machine. In addition, the measurement results from the smart phone were compared with FEM analysis results.
Humanoid Robot Footstep Planner with Fuzzy-Based Multi-Criteria Decision Making
Lee, Ki-Baek ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 441~447
DOI : 10.7735/ksmte.2015.24.4.441
This paper proposes a novel fuzzy-based multi-criteria decision making method and implements a footstep planner for humanoid robots with it. Humanoid robots require additional footstep planning process in addition to path planning for the autonomous navigation. Moreover, it is necessary to consider safety and energy consumption as well as path efficiency and multi-criteria decision making is indispensable. The proposed method can provide not only well- distributed and non-dominated, but also more preferable solutions for users. The planned footsteps by the proposed method were verified through simulation. The results indicate that the user`s preference is properly reflected in optimized solutions maintaining solution quality.
Manufacturing of PAR Illumination Using COB Line Type LEDs
Youn, Gap-Suck ; Yoo, Kyung-Sun ; Lee, Chang-Soo ; Hyun, Dong-Hoon ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 448~454
DOI : 10.7735/ksmte.2015.24.4.448
In this paper, the band structural design that is typically in a line was arranged in a ring shape, so as to configure the high power LED lighting in such a way as to form a concentrated light distribution angle of less than 15 degrees. The parabolic aluminized reflector PAR38 that facilitates design using area and the area of the optical system to the same extent, applied a multiple light-source condenser lens optical system for the control of integration. The LED used here implemented a single linear light source using ans LED module with ans LED, flip-chip chip-scale package. The optical system was designed based on the energy star standard.
Methods of Making Samples for a Visual Experiment with Feature Lines of Outer Automotive Panels
Han, Juho ; Chung, Yunchan ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 455~462
DOI : 10.7735/ksmte.2015.24.4.455
A feature line is a visually noticeable creased line on outer automotive panels. Feature lines play an important role in creating a good impression of a car. Even though the manufacturing quality of feature lines is important, it is difficult to achieve the designed shape owing to the springback of sheet metal. The current study presents five methods of making samples that will be used in a visual experiment to discover a quality control quantitative manufacturing allowance for feature lines. Measurement and inspection methods for the samples are also presented. The results show that plunge machining is the most accurate way to make the desired shape, and that wrapping the machined surface with sheet film is an appropriate way to emulate the roughness and visual texture of the painted outer panels of a car.
Investigation of the Cause of High Vibration in a Low Pressure Turbine Casing with Manufacturing Defects by Frequency Response Analysis
Youn, Hee-Chul ; Woo, Chang-Ki ; Hwang, Jai-Kon ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 463~468
DOI : 10.7735/ksmte.2015.24.4.463
High vibration of a low pressure (LP) turbine casing caused safety problems and life at the facility it was housed in. The main focus of this study was the cause of the high vibration in a low pressure turbine casing with manufacturing defects by frequency response analysis, compared with the results of experiments. Therefore, excited accelerations were obtained from the LP casing fundamental, and frequency responses were analyzed. The measurement and the modal analysis showed that the natural frequency of the LP turbine casing was 61.26 Hz and the excited frequency of the turbine rotor was 60.25 Hz. The manufacturing defect caused a decrease in the casing natural frequency and resulted in the high vibration of the casing because it moved close to the resonant frequency.
Improvement of Deposition Performance of Ultrasonic Spray Pyrolysis Deposition System through Atomizer Shape Modification
Kim, Kyu-Eon ; Lee, Jae-Hoo ; Jeon, Jae-Keon ; Park, Sung-Hwan ; Lee, Chibum ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 24, issue 4, 2015, Pages 469~474
DOI : 10.7735/ksmte.2015.24.4.469
In ultrasonic spray pyrolysis deposition, a precursor solution is evaporated by an ultrasonic atomizer, then gas-carried into a furnace where the solute is separated from the water vapor. After condensation, polymerization, and nucleation, the solute oxide forms a thin film. To improve the deposition efficiency, the ultrasonic atomizer was studied to optimize the evaporated gas flow. The vat cover was redesigned, using three versions with different inlet factors being tested through a computational fluid dynamic analysis as well as a water evaporation experiment. The atomization rate with a hemispherical cover with a
inlet was found to be 2.4 times higher than that with the original. This improvement was verified with fluorine-doped tin oxide spray pyrolysis deposition. The film obtained with the modified vat cover was 2.4 times thicker than that obtained with the original vat cover.