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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
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Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 30, Issue 12 - Dec 2013
Volume 30, Issue 11 - Nov 2013
Volume 30, Issue 10 - Oct 2013
Volume 30, Issue 9 - Sep 2013
Volume 30, Issue 8 - Aug 2013
Volume 30, Issue 7 - Jul 2013
Volume 30, Issue 6 - Jun 2013
Volume 30, Issue 5 - May 2013
Volume 30, Issue 4 - Apr 2013
Volume 30, Issue 3 - Mar 2013
Volume 30, Issue 2 - Feb 2013
Volume 30, Issue 1 - Jan 2013
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Development of Spray Thin Film Coating Method using an Air Pressure and Electrostatic Force
Kim, Jung Su ; Kim, Dong Soo ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 567~572
DOI : 10.7736/KSPE.2013.30.6.567
In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem, it is difficult to apply to a continuous process such as a R2R(roll to roll) printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, an electrostatic atomizer sprays micro-drops from the solution injected into the capillary with electrostatic force generated by electric potential of about several tens kV. The organic solar cell based on a P3HT/PCBM active layer and a PEDOT:PSS electron blocking layer prepared from ESD method shows solar-to-electrical conversion efficiency of 1.42% at AM 1.5G 1sun light illumination, while 1.86% efficiency is observed when the ESD deposition of P3HT/PCBM is performed on a spin-coated PEDOT:PSS layer.
Effect of Properties of Conductive Ink on Printability of Electrode Patterning by Gravure Printing Method
Nam, Ki Sang ; Yoon, Seong Man ; Lee, Seung-Hyun ; Kim, Dong Soo ; Kim, Chung Hwan ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 573~577
DOI : 10.7736/KSPE.2013.30.6.573
The one of the most important issue in roll-to-roll gravure printing is increase of ink transfer ratio or printability. As the result of high ink transfer ratio or printability, we can assess the quality of the printed patterns. The rheological properties are the important factors for the printability of electrodes patterning. In this study, the rheological properties of conductive ink are controlled by adding the solvent. The inks with different rheological properties are used for the patterning of the electrodes of
by gravure printing equipment. The various printing speed, which also affect the rheological properties of conductive ink, is applied and the printed patterns are compared for their width and aspect ratio. Decreasing in the ink viscosity as well as increasing in the printing speed decreases the printability in gravure patterning, which shows that the rheological properties are important factors for the printability of gravure patterning.
A Study on Processing of Auxiliary Electrodes for OLED Lighting Devices Using a Reverse Gravure-Offset or Gravure-Offset Printing
Bae, Sung Woo ; Kwak, Sun Woo ; Kim, In Young ; Noh, Yong-Young ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 578~583
DOI : 10.7736/KSPE.2013.30.6.578
The lighting devices using organic light emitting diodes (OLEDs) are actively researched because of the various advantages such as high power efficiency and 2-dimensitonal lighting emitting. To commercialize those OLED lighting devices, the manufacturing cost must be downed to comparable price with conventional light sources. Here, we demonstrate a reverse gravure-offset or gravure off-set printed metal electrode for the auxiliary electrode for OLED lighting devices. For the fabricated OLED`s auxiliary electrode, we used Ag nano-paste and printed metal grid structure with a line width and spacing of several ten and hundred micrometer by using gravure-offset printing. In the end the printing metal grid pattern are successfully achieved by optimization of various experimental conditions such as printing pressure, printing speed and printing delay time.
Development of a Wireless Bar Coater Applied to Organic Solar Cells
Yu, Semin ; Yu, Young Jae ; Moon, Heekwang ; Kim, Jung Su ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 584~588
DOI : 10.7736/KSPE.2013.30.6.584
Studies are using a roll forming bar. A bar coating device available for a variety of coating conditions was developed. It is characterized by the bar forward and reverse rotation, fine-tune coating speed, and stripe coating. To determine the characteristics of the equipment, the coating tests under different coating conditions were carried out. As a result of the coating tests, the equipment was confirmed as one of strong candidates for the production tool of organic solar cells. The further production test of organic solar cells through stripe coating is in progress.
Improvement of Inverted Hybrid Organic Light-emitting Diodes Properties with Bar-coating Process
Kwak, Sun-Woo ; Yu, Jong-Su ; Han, Hyun-Suk ; Kim, Jung-Su ; Lee, Taik-Min ; Kim, Inyoung ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 589~595
DOI : 10.7736/KSPE.2013.30.6.589
Solution processed conjugated molecules enable to manufacture various electronic devices by unconventional and cost effective patterning methods as screen or gravure printing. Spin-coating is the most popularly used method to form conjugated polymeric film for various electronic devices. The coating method has certain disadvantages such as a large amount of unwanted wastes, difficulty forming a film with a large area, and impossible to apply roll-to-roll manufacturing. We present here a promising alternative coating method, bar-coating for conjugated polymer film and OLED with the bar coated light emitting layer. In this papers, we show atomic force microscope images of spin- and bar-coated Poly[(9,9-di-n-octylfluorenyl-2,7-diyl)-alt-(benzo[2,1,3]thiadiazol-4,8-diyl)] (F8BT) films on substrate. The bar-coated film showed a slight lower RMS roughness (1.058 [nm]) than spin-coated film (1.767 [nm]). It means the bar-coating is suitable method to form light emitting layers in OLEDs. By using bar-coating process, an OLED obtained with 4.7 [cd/A] in maximum current efficiency.
Technology of thin Film Formation by Using the Micro Gravure Coater
Kim, Dong Soo ; Kim, Jung Su ; Bae, Sung Woo ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 596~600
DOI : 10.7736/KSPE.2013.30.6.596
We report here on the processing and manufacturing of thin film for printed electronics by micro-gravure coating system. The micro-gravure coating systems are consisted of various modules such as web and system tension controller, micro-gravure coating units, dispenser and hybrid dry units (UV, NIR, Hot air). Especially, for the optimization of system, the number of idle roller was minimized and tension isolating infeeder was included. Also, we applied four patterns circle, 45 degree, square and 35 degree for the optimizing coating thickness. The micro-gravure coating system which applied various patterns to enable continuous coating process and fast coating time compare with conventional batch coating system. In this paper, introduce of micro-gravure coating system and testing results of coating thickness (20~700nm), coating time (1~2sec) and surface roughness (3~12nm) by using micro-gravure coating system.
Feature Detection using Measured 3D Data and Image Data
Kim, Hansol ; Jung, Keonhwa ; Chang, Minho ; Kim, Junho ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 601~606
DOI : 10.7736/KSPE.2013.30.6.601
3D scanning is a technique to measure the 3D shape information of the object. Shape information obtained by 3D scanning is expressed either as point cloud or as polygon mesh type data that can be widely used in various areas such as reverse engineering and quality inspection. 3D scanning should be performed as accurate as possible since the scanned data is highly required to detect the features on an object in order to scan the shape of the object more precisely. In this study, we propose the method on finding the location of feature more accurately, based on the extended Biplane SNAKE with global optimization. In each iteration, we project the feature lines obtained by the extended Biplane SNAKE into each image plane and move the feature lines to the features on each image. We have applied this approach to real models to verify the proposed optimization algorithm.
A Study on the Effect of the Sensor Gain Error in the Precision Measurement of Straightness Error Using Mixed Sequential Two-Probe Method
Jeong, Ji Hun ; Oh, Jeong Seok ; Kihm, Gyungho ; Park, Chun Hong ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 607~614
DOI : 10.7736/KSPE.2013.30.6.607
In this study, effect of the sensor gain error is theoretically analyzed and simulated when mixed sequential two-prove method(MTPM) is applied for the precision measurement of straightness error of a linear motion table. According to the theoretical analysis, difference of the gain errors between two displacement sensors increases measurement error dramatically and alignment error of the straightedge is also amplified by the sensor gain difference. On the other hand, if the gain errors of the two sensors are identical, most of error terms are cancelled out and the alignment error doesn`t give any influence on the measurement error. Also the measurement error of the straightness error is minimized compared with that of the straightedge`s form error owing to close relationship between straightness error and angular motion error of the table in the error terms.
Robotic Workplace Calibration Using Teaching Data of Work-Piece Fixed in Robotic Workplace for Robot Off-line Programming
Jeong, Jun Ho ; Kuk, Kum Hoan ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 615~621
DOI : 10.7736/KSPE.2013.30.6.615
The robot calibration has greatly improved the absolute accuracy of the industrial robot. However, the accuracy of the relative positions of robotic tool-tip at work-points on a work-piece is only slightly corrected by the robot calibration since there has been no practical method to eliminate the elements of the setup position errors at a robotic workplace. A robotic workplace calibration is demonstrated in this paper to minimize the relative position errors between a robot tool-tip and the work-point on a work-piece. The existing teaching and playback method has been developed for the robotic workplace calibration. This paper uses the work-piece fixed in a robotic work-place as measurement equipment instead of a special robot measurement equipment for the robotic workplace calibration. The positive effect of the robotic workplace calibration is supported by the results of computer simulation on an ideal robotic workplace model and an experiment at the actual robotic workplace.
A Study on the Friction of Tire Tread Rubber using High-Speed Friction Test Machine
Lee, Jin Koo ; Lee, Dong Ju ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 622~628
DOI : 10.7736/KSPE.2013.30.6.622
Due to the development of compounding technology, there is a considerable increase in the number of high performance rubbers in the world. Accordingly, there are rapid growing requests about high performance tires such as UHP tire and Run-flat tire. However, it is extremely difficult to investigate the friction coefficient of tire tread rubbers. An alternative solution must be developed with the reliability of high-speed linear friction test machines. The use of friction test machines can be expected to improve rubber friction researches. In this paper, we propose a new kind of high-speed linear friction test machine. We have designed and manufactured various mechanisms for friction tests. The final goals are to design and manufacture friction test machines that can investigate friction coefficients efficiently and rapidly. The performance of the proposed high-speed linear friction test machine is evaluated experimentally; however additional study should be necessary for safer and more reliable experimentation.
A Study on D.D.I. Load for Forming of the CNG Storage Vessel
Lee, Hyun Woo ; Bae, Jun Ho ; Kim, Chul ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 629~637
DOI : 10.7736/KSPE.2013.30.6.629
In this study, a theoretical analysis method was suggested for predicting forming loads of continuous deep drawing and ironing processes (D.D.I. processes) by considering back tension and continuity equation, and FEA for D.D.I. processes was performed. Dimensions of a punch and a mold on the basis of design rules for a CNG storage vessel were applied for the analysis. To verify the suggested theoretical analysis, the results of theoretical analysis were compared with both those of FEA and experiments of previous studies. As the result of analysis, the values and tendencies of the loads predicted by the theoretical analysis were in agreement with those of FEA and the experiments. So, it is considered that the analysis suggested has reliability for predicting the forming loads of the continuous processes(deep drawing+ironing(1)+ironing(2)).
Laser Micro Machining and Electrochemical Etching After Surface Coating
Kim, Tae Pung ; Park, Min Soo ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 638~643
DOI : 10.7736/KSPE.2013.30.6.638
Laser beam machining (LBM) is fast, contactless and able to machine various materials. So it is used to cut metal, drill holes, weld or pattern the imprinted surface. However, after LBM, there still leave burrs and recast layers around the machined area. In order to remove these unwanted parts, LBM process often uses electrochemical etching (ECE). But, the total thickness of workpiece is reduced because the etching process removes not only burrs and recast layers, but also the entire surface. In this paper, surface coating was performed using enamel after LBM on metal. The recast layer can be selectively removed without decreasing total thickness. Comparing with LBM process only, the surface quality of enamel coating process was better than that. And edge shape was also maintained after ECE.
Surface Polishing of Polymer Microlens with Solvent Vapor
Kim, Sin Hyeong ; Song, Jun Yeob ; Lee, Pyeong An ; Kim, Bo Hyun ; Oh, Young Tak ; Cho, Young Hak ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 644~649
DOI : 10.7736/KSPE.2013.30.6.644
Today, there are lots of progresses in the field of lens researches, especially in the microlens fabrication. Unlike normal lenses, microlens has been widely used as a role of improving the performance of photonic devices which increase the optical precision, and also used in the fields of the display. In this paper, polymer microlenses with
diameter were replicated through hot-embossing from nickel mold which was fabricated by micro-EDM. After hot-embossing process, the polymer microlenses have a rough surface due to the crater formed by micro-EDM process, which is projected onto the surface of the lenses. The surface of polymer microlenses was polished using solvent vapor to improve the surface roughness of the microlenses without changing their shape. In the experiment, the surface roughness was improved with the processing time and vapor temperature. Also, the roughness improvement was greatly affected by the solubility difference between polymer and solvent.
Torque Estimation of the Human Elbow Joint using the MVS (Muscle Volume Sensor)
Lee, Hee Don ; Lim, Dong Hwan ; Kim, Wan Soo ; Han, Jung Soo ; Han, Chang Soo ; An, Jae Yong ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 650~657
DOI : 10.7736/KSPE.2013.30.6.650
This study uses a muscle activation sensor and elbow joint model to develop an estimation algorithm for human elbow joint torque for use in a human-robot interface. A modular-type MVS (Muscle Volume Sensor) and calibration algorithm are developed to measure the muscle activation signal, which is represented through the normalization of the calibrated signal of the MVS. A Hill-type model is applied to the muscle activation signal and the kinematic model of the muscle can be used to estimate the joint torques. Experiments were performed to evaluate the performance of the proposed algorithm by isotonic contraction motion using the KIN-COM
equipment at 5, 10, and 15Nm. The algorithm and its feasibility for use as a human-robot interface are verified by comparing the joint load condition and the torque estimated by the algorithm.
Performance Characterization of Polyaniline Coated Electro-Active Paper Actuator
Ko, Hyun-U ; Mun, Seong Cheol ; Zhai, Lindong ; Kim, Ki-Baek ; Kim, Jaehwan ;
Journal of the Korean Society for Precision Engineering, volume 30, issue 6, 2013, Pages 658~664
DOI : 10.7736/KSPE.2013.30.6.658
Bending actuators composed of cellulose with an electrically conducting polymer (CP) are fabricated and their performance is characterized in the air. Two different counter ions, perchlorate and tetrafluoroborate are used as dopant ions in the polyaniline CP processing. CP-cellulose-CP trilayer and CP-cellulose bilayer samples are fabricated with different dopant ions, and their actuation performance is evaluated in terms of tip displacement, blocked force and electrical power consumption along with the humidity level and actuation frequency. The trilayer samples substantially enhanced the tip displacement compared to the bilayer ones. The actuation performance of the trilayer actuator is three times better than that of original cellulose electro-active paper (EAPap) actuator. The displacement and blocked force of CP-EAPap actuators are dependent on the humidity and frequency.