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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
Journal Basic Information
Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 27, Issue 12 - Dec 2010
Volume 27, Issue 11 - Nov 2010
Volume 27, Issue 10 - Oct 2010
Volume 27, Issue 9 - Sep 2010
Volume 27, Issue 8 - Aug 2010
Volume 27, Issue 7 - Jul 2010
Volume 27, Issue 6 - Jun 2010
Volume 27, Issue 5 - May 2010
Volume 27, Issue 4 - Apr 2010
Volume 27, Issue 3 - Mar 2010
Volume 27, Issue 2 - Feb 2010
Volume 27, Issue 1 - Jan 2010
Selecting the target year
Roll-to-Roll Contact Printer with Multiple Printing Methods
Kim, Chung-Hwan ; Kim, Myoung-Sub ; You, Ha-Il ; Choi, Byoung-Oh ; Lee, Seung-Hyun ; Kim, Dong-Soo ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 7~10
Recently, roll-to-roll printers are being developed actively by various research teams such as research institutes, universities and companies for the application of printed electronics. The printing methods that are widely used in the roll-to-roll printing equipments are gravure, gravure and flexo, which depend on the inks used and electronic devices produced. In general, a single printing unit of roll-to-roll printing equipment adopts only one printing method and this method is not changeable, which limits the application fields of the developed printing equipments. In this paper, the roll-to-roll printer, in which the printing unit has the novel design concept, is described.
Study and Fabrication of Transparent Electrode Film by using Thermal-Roll Imprinted Ag Mesh Pattern and Coated Conductive Polymer
Yu, Jong-Su ; Jo, Jeong-Dai ; Yoon, Seong-Man ; Kim, Do-Jin ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 11~15
In this study, to fabricate a low-resistance and high optical transparency electrode film, the following steps were performed: the design and manufacture of electroforming stamp, the fabrication of a thermal roll-imprinted polycarbonate (PC) patterned films, the filled low-resistance Ag paste using doctor blade process on patterned PC films and spin coating by conductive polymers. As a result of PC films imprinted line width of
, channel length of
, and pattern depth of
. Ag paste to fill part of the patterned film with conductive polymer coating and then the following parameters were obtained: a sheet resistance of
optical transparency values at a wavelength of 550 nm was 80.31 %.
Design and Development of Gravure Offset Printing System
Noh, Jae-Ho ; Lee, Taik-Min ; Park, Sang-Ho ; Jo, Jeong-Dai ; Kim, Dong-Soo ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 16~19
This paper presents how to design and fabricate the gravure offset printing system for enhancement of register precision. Factors of precision error are caused by imprecision of gravure plate, deformation of substrate, printing quality change due to the change of ink viscosity, Imprecision of printing machine, and so on. This study suggests concept design of gravure offset printing system which is able to minimize or remove these error factors.
Effect of Micro Surface Structure on Printed Electronics
Kim, Seung-Hwan ; Kang, Hyun-Wook ; Lee, Kyung-Heon ; Sung, Hyung-Jin ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 20~25
The effect of micro surface structure on printing for printed electronics has been studied experimentally. The photolithography MEMS fabricationwass used to make a SU-8 molder which has micro structures on the surface, and the PDMS micro structure was fabricated by the PDMS molding method. In the aspect of printed electronics, we used silver paste conductive ink. We measured the surface energy variation on pillar microstructure. The microstructure was used to real printing experiment by a screen printing. We printed 1cm micro lines which have
width, and checked the conductivity to sort out opened line pattern. Printability was defined by success probability of printed patterns and we found that the present microstructures improve the printability significantly.
Mechanical Loads Analysis and Control of a MW Wind Turbine
Nam, Yoon-Su ; Choi, Han-Soon ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 26~33
A multi-MW wind turbine is a huge mechanical structure, of which the rotor diameter is more or less than 100 m. Rotor blades experience unsymmetric mechanical loads caused by the interaction of incoming wind with the tower and wind shear effect. These mechanical loads are transferred to the entire structure of the wind turbine and are known as the major reasons for shortening the life span of the wind turbine. Therefore, as the size of wind turbine gets bigger, the mitigation of mechanical loads becomes more important issue in wind turbine control system design. In this paper, a concept of an individual pitch control(IPC), which minimizes the mechanical loads of rotor blades, is introduced, and simulation results using IPC are discussed.
Development of Semi-Autonomous Pesticide Spray Robot for Glass House Rose Farming
Kim, Kyoung-Chul ; Ryuh, Beom-Sahng ; Yang, Chang-Wan ; Jang, Kyo-Gun ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 34~42
Agricultural automation has become more and more important by environmental change. The automation demands the highest technology due to the ever changing various conditions in agriculture system. In the paper, semi-autonomous pesticide spray robot system has been developed for rose farming in the glass house. The robot is in autonomous mode during pesticide spraying process driven on pipe rail. The robot is manually driven while moving from a rail to the next rail. The drive platform and autonomous operation control system are developed based on IT fusion technology. The pesticide spray system is also developed with nozzles and booms for precision mist spray system. Experimental data of nozzle test is also included.
Design of a Low-Vibration Micro-Stepping Controller for Pan-Tilt Camera
Yoo, Jong-won ; Kim, Jung-han ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 43~51
Speed, accuracy and smoothness are the important properties of pan-tilt camera. In the case of a high ratio zoom lens system, low vibration characteristic is a crucial point in driving pan-tilt mechanism. In this paper, a novel micro-stepping controller with a function of reducing vibration was designed using field programmable gate arrays (FPGA) technology for high zoom ratio pan-tilt camera. The proposed variable reference current (VRC) control scheme reduces vibration decently and optimizing coil current in order to prevent the step motor from occurring missing steps. By employing VRC control scheme, the vibration in low speed could be significantly minimized. The proposed controller can also make very high speed of 378kpps micro-step driving, and increase maximum acceleration in motion profiles.
Fracture Analysis of Bone-Like Materials Using J integral
Lee, Chang-Woo ; Lin, Song ; Beom, Hyeon-Gyu ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 52~57
The analysis of a crack in a bone-like material is performed numerically. The bone-like material is hierarchically structured and each hierarchy is structured by mineral platelets and protein matrix through staggered arrangement. Mechanical behavior of the composite can be analyzed using tension shear chain model. The Dugdale model is adopted to evaluate the fracture energy of Bone-like material. The fracture energy dissipation is assumed to concentrate within a strip near the crack tip along the prospective crack path. Fracture criterion of the bone-like material is estimated by using J integral. Effects of hierarchical level, ratio of elastic modulus of mineral to protein, aspect ratio of mineral platelet and volume fraction on J integral are investigated. It is found that the J integral decreases as elastic modulus ratio and hierarchy level increase. It is also shown that the J integral increases as the volume fraction and aspect ratio decrease.
Comparison of Experimental and Numerical Analysis for Durability Design Criteria in Ceramic Catalyst Substrate
Beak, Seok-Heum ; Cho, Seok-Swoo ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 58~66
This study examines thermal safety on three-way catalyst that dominates 70 % among whole exhaust gas purification device in 2003. Three-way catalyst durability in the Korea requires 5 years/80,000 km in 1988 but require 10 years/120,000 km after 2002. Three-way catalyst durability in the USA requires 7 years/120,000 km but require 10 years/160,000 km after 2004. Three-way catalyst maintains high temperature in interior domain but maintains low temperature on outside surface. Therefore this device shows tensile stress on outside surface. Temperature distribution of three-way catalyst was acquired by thermal flow analysis for predicted thermal flow parameter. Thermal stress analysis for three-way catalysis was performed based on this temperature distribution. Thermal safety of three-way catalyst was estimated by power law dynamic fatigue life estimation and strength reduction methods for thermal stress.
Development of an Automated Integrated Design System for Gerotor Pumps with Multiple Profiles(Ellipse and Involute)
Moon, Hyun-Ki ; Jung, Sung-Yuen ; Bae, Jun-Ho ; Chang, Young-June ; Kim, Chul ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 67~77
An internal lobe pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular, the pump is an essential machine element of an automotive engine to feed lubricant oil. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the rotors: usually the outer one is characterized by lobe with elliptical and involute shapes, while the inner rotor profile is determined as conjugate to the other. And the integrated design system which is composed of three main modules has been developed through AutoLISP under AutoCAD circumstance plus CFD-ACE+. It generates new lobe profile and calculates automatically the flow rate and flow rate irregularity according to the lobe profile generated. CFD simulation results show trends similar to those carried out in experiments, and a quantitative comparison is presented. Results obtained from the automotive integrated design system enable the designer and manufacturer of oil pump to be more efficient in this field.
Creep Characteristic of the Polycarbonate(PC) at Various Stresses and Temperatures
Kang, Suk-Choon ; Lee, Young-Won ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 78~85
Creep characteristic is an important failure mechanism when evaluating engineering materials that are soft material as polymers or used as mechanical elements at high temperatures. One of the popular thermo-elastic polymers, Polycarbonate(PC) which is used broadly for engineering polymer, as it has excellent mechanical and thermal properties compared to other polymers, was studied for creep characteristic at various level of stresses and temperatures. From the experimental results, the creep limit of PC at room temperature is 85 % of tensile strength. which is higher than PE (75%)at room temperature. Also the creep limits decreased exponentially as the temperatures increased, up to 50 % of the melting point(
). Also the first and third stage among the three creep stages was non-existent nor was there any rupture failure which occurred for many metals.
Prediction of Relative Deformation between Cutting Tool and Workpiece by Cutting Force [
Hwang, Young-Kug ; Lee, Choon-Man ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 86~93
Any relative deformation between the cutting tool and the workpiece at the machining point, results directly in form and dimensional errors. The source of relative deformations between the cutting tool and the workpiece at the contact point may be due to thermal, weight, and cutting forces. Thermal and weight deformations can be measured at various positions of the machine tool and stored in the compensation registers of the CNC unit and compensated the errors during machining. However, the cutting force induced errors are difficult to compensate because estimation of cutting forces are difficult. To minimize the error induced by cutting forces, it is important to improve the machining accuracy. This paper presents the pre-calculated method of form error induced by cutting forces. In order to estimate cutting forces, Isakov method is used and the method is verified by comparing with the experimental results. In order to this, a cylindrical-outer-diameter turning experiments are carried out according to cutting conditions.
A Study on the Optimum Shrink-fit for High Speed Ball Bearing of Machine Tool
Kim, Woong ; Lee, Choon-Man ; Hwang, Young-Kug ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 94~102
The spindle is the main component in machine tools. To develop high speed machine tools, a lot of studies have been carried out for high speed spindle. Bearing is very important part in spindle. The bearing clearance is influenced by shrink fit and thermal expansion during operation. The designer must take into account the reduction of shrink fits. The aims of this study are to grasp the shrink fits and behavior of a bearing which is a deeply connected with fatigue life of bearing and performance of spindle through FEM(Finite Element Method). This paper proposed optimum value of shrink fit considering deformation of spindle and stress of fitting area using design of experiments. Thus, the proposed formula can be used to obtain bearing internal clearance.
Stress and Deformation Analysis of a Tool Holder Spindle using
Kwon, Koo-Hong ; Chung, Won-Jee ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 9, 2010, Pages 103~110
This paper presents the optimized approximation of finite element modeling for a complex tool holder spindle using both DOE (Design of Experiment) with Optimal Latin Hypercube (OLH) method and approximation modeling method with Radial Basis Function (RBF) neural network structure. The complex tool holder is used for holding a (milling/drilling) tool of a machine tool. The engineering problem of complex tool holder results from the twisting of spindle of tool holder. For this purpose, we present the optimized approximation of finite element modeling for a complex tool holder spindle using both DOE (Design of Experiment) with Optimal Latin Hypercube (OLH) method (specifically a module of
FD-3.1) and approximation modeling method with Radial Basis Function (RBF) (another module of
FD-3.1) neural network structure