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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
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 24, Issue 12 - Dec 2007
Volume 24, Issue 11 - Nov 2007
Volume 24, Issue 10 - Oct 2007
Volume 24, Issue 9 - Sep 2007
Volume 24, Issue 8 - Aug 2007
Volume 24, Issue 7 - Jul 2007
Volume 24, Issue 6 - Jun 2007
Volume 24, Issue 5 - May 2007
Volume 24, Issue 4 - Apr 2007
Volume 24, Issue 3 - Mar 2007
Volume 24, Issue 2 - Feb 2007
Volume 24, Issue 1 - Jan 2007
Selecting the target year
Research on Defect Inspection of LCD Panel
Kim, Jong-Hyeong ; Ko, Kuk-Won ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 7~14
An Algorithm Development for Detecting Blister Defects of Display Glasses
Oh, Choon-Suk ; Ryu, Young-Kee ; Shin, Seung-Jung ; Yoo, Hyeon-Joong ; Jun, Byung-Uk ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 15~20
Pole Height Inspection on LCD Glass via High Speed White Light Interferometry
Ko, Kuk-Won ; Ko, Kyung-Cheol ; Kim, Jong-Hyeong ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 21~28
Enhancement of Illumination Irregularity for the 2D Blot Detection Under Low Contrast
Rew, Keun-Ho ; Nam, Taek-Hoon ; Joo, Hyo-Nam ; Ko, Kuk-Won ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 29~35
Development of an Optical Sensor for Inspection the Shape of the Transparent Flat Glass for Flat Panel Display
Seo, Pyeong-Won ; Ryu, Young-Kee ; Oh, Choon-Suk ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 36~43
A Study on the Vision Inspection System for the Defects Detection of Micro-BGA Device
Park, Young-Soon ; Kim, Joon-Seek ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 44~56
Characteristics of Surface Hardening for Hot Work Tool Steel using Continuous Wave Nd:YAG Laser
Shin, Ho-Jun ; Shin, Byung-Heon ; Yoo, Young-Tae ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 57~67
Laser surface hardening technologies have been used to improve characteristics of wear and to enhance the fatigue resistance fur mold parts. The objective of this research work is to investigate the influence of the process parameters, such as power of laser and defocused spot position, on the characteristics of laser surface hardening for the case of SKD61 steel. CW Nd:YAG laser is selected as the heat source. The optical lens with the elliptical profile is designed to obtain a wide surface hardening area with a uniform hardness. From the results of the experiments, it has been shown that the maximum average hardness is approximatly 780 Hv when the power, focal position and the travel of laser are 1,095 W, 0mm and 0.3 m/min, respectively. In samples treated with lower scanning speeds, some small carbide particles appear in the interdendritic regions. This region contains fine martensite and carbide in proportions which depend on the local thermal cycle.
The Posture Control of One-wheel Unicyle Robot Using Partial Feedback Linearization
Kim, Jin-Seok ; Cho, Young-Jin ; Kim, Young-Tark ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 68~75
In this study, the ultimate goal is to acquire stability when turning around efficiently by using the controller which is applied partial feedback linearization of One-wheel Unicycle Robot. When moving around, linear controller could result in unstable factor according to widening operation range. So in order to reduce instability, 1 have developed Non-linear Controller using Partial Feedback Linearization. Compared with linear controller, Non-linear Controller guarantees the superiority of Regulating Control and Tracking Control in direct and also revolution motion of Robot. I'm sure of the Non-linear controller performance through many experiments.
Development of a Neural Network Classifier for the Classification of Surface Defects of Cold Rolled Strips
Moon, Chang-In ; Choi, Se-Ho ; Kim, Gi-Bum ; Kim, Cheol-Ho ; Joo, Won-Jong ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 76~83
A new neural network classifier is proposed for the automatic real-time surface inspection of high-speed cold steel strips having 11 different types of defects. 46 geometrical and gray-level features are extracted for the defect classification. 3241 samples of Posco's Kwangyang steel factory are used for training and testing the neural network classifier. The developed classifier produces plausible 15% error rate which is much better than 20-30% error rate of human vision inspection adopted in most of domestic steel factories.
Multi-Objective Genetic Algorithm for Machine Selection in Dynamic Process Planning
Choi, Hoe-Ryeon ; Kim, Jae-Kwan ; Lee, Hong-Chul ; Rho, Hyung-Min ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 84~92
Dynamic process planning requires not only more flexible capabilities of a CAPP system but also higher utility of the generated process plans. In order to meet the requirements, this paper develops an algorithm that can select machines for the machining operations by calculating the machine loads. The developed algorithm is based on the multi-objective genetic algorithm that gives rise to a set of optimal solutions (in general, known as the Pareto-optimal solutions). The objective is to satisfy both the minimization number of part movements and the maximization of machine utilization. The algorithm is characterized by a new and efficient method for nondominated sorting through K-means algorithm, which can speed up the running time, as well as a method of two stages for genetic operations, which can maintain a diverse set of solutions. The performance of the algorithm is evaluated by comparing with another multiple objective genetic algorithm, called NSGA-II and branch and bound algorithm.
Development of Statistical Model and Neural Network Model for Tensile Strength Estimation in Laser Material Processing of Aluminum Alloy
Park, Young-Whan ; Rhee, Se-Hun ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 93~101
Aluminum alloy which is one of the light materials has been tried to apply to light weight vehicle body. In order to do that, welding technology is very important. In case of the aluminum laser welding, the strength of welded part is reduced due to porosity, underfill, and magnesium loss. To overcome these problems, laser welding of aluminum with filler wire was suggested. In this study, experiment about laser welding of AA5182 aluminum alloy with AA5356 filler wire was performed according to process parameters such as laser power, welding speed and wire feed rate. The tensile strength was measured to find the weldability of laser welding with filler wire. The models to estimate tensile strength were suggested using three regression models and one neural network model. For regression models, one was the multiple linear regression model, another was the second order polynomial regression model, and the other was the multiple nonlinear regression model. Neural network model with 2 hidden layers which had 5 and 3 nodes respectively was investigated to find the most suitable model for the system. Estimation performance was evaluated for each model using the average error rate. Among the three regression models, the second order polynomial regression model had the best estimation performance. For all models, neural network model has the best estimation performance.
Development of porthole Die on Aluminum Extrusion for the Automobile Control Arm
Joe, Young-June ; Lee, Sang-Kon ; Oh, Kae-Hee ; Park, Sang-Woo ; Lee, Woo-Sik ; Jang, Gae-Won ; Kim, Byung-Min ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 102~108
The characteristic properties of aluminum, high strength stiffness to weight ratio, good formability, good corrosion resistence, and recycling potential make it the ideal candidate to replace heavier materials in the car to respond to the weight reduction demand within the automotive industry. In this paper, FE simulation was carried out to design an appropriate extrusion die for the automobile control arm. Based on the FE simulation result, a new die design has been proposed for uniform material flow in the cross section of extruded product. And then the welding pressure, extrusion load, and the tendency of mandrel deflection were estimated to verify high quality. In the extrusion experiment, it was possible to produce sound product without defects.
Mobility in the Contact Joint of a Mechanism
Lee, Jang-Yong ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 109~114
The mobility (degree of freedom) of mechanisms can be regarded as independent coordinate to define its position. This concept is essential for kinematics, and for designing mechanisms in the practical point of view. Gruebler's equation has been applied to estimate the mobility using number of links and joints of a mechanism. In practical case, there are many types of mechanisms, which transfer motion by direct contact between two links. However, no exact kinematic definition has existed for the joint that the contact takes place in a mechanism. In this paper, a new concept of contact joint is defined and modified Gruebler's equation is suggested to calculate mobility of a mechanism with the joint. This concept would be useful in mechanism design because it will be possible to manage many contact mechanisms with kinematic exactness.
A Study on Flow Characteristics of PBK40 for Glass Lens Forming Process Simulation Using a Plate Heating Type
Chang, Sung-Ho ; Yoon, Gil-Sang ; Shin, Gwang-Ho ; Lee, Young-Min ; Jung, Woo-Chul ; Kang, Jeong-Jin ; Jung, Tae-Sung ; Kim, Dong-Sik ; Heo, Young-Moo ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 115~122
Recently, remarkable progress has been made in both technology and production of optical elements including aspheric lens. Especially, requirements for machining glass materials have been increasing in terms of limitation on using environment, flexibility of material selection and surface accuracy. In the past, precision optical glass lenses were produced through multiple processes such as grinding and polishing, but mass production of aspheric lenses requiring high accuracy and having complex profile was rather difficult. In such a background, the high-precision optical GMP process was developed with an eye to mass production of precision optical glass parts by molding press. This GMP process can produce with precision and good repeatability special form lenses such as camera, video camera, aspheric lens for laser pickup,
lens for laser printer and prism, and me glass parts including diffraction grating and V-grooved base. GMP process consist a succession of heating, forming, and cooling stage. In this study, as a fundamental study to develop molds for GMP used in fabrication of glass lens, we conducted a glass lens forming simulation. In prior to, to determine flow characteristics and coefficient of friction, a compression test and a compression farming simulation for PBK40, which is a material of glass lens, were conducted. Finally, using flow stress functions and coefficient of friction, a glass lens forming simulation was conducted.
A Study on Fretting Fatigue Life Prediction for Cr-Mo Steel(SCM420)
Kwak, Dong-Hyeon ; Roh, Hong-Rae ; Kim, Jin-Kwang ; Cho, Sang-Bong ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 123~130
Recently, a lot of work and interest have been devoted to the development of multiaxial fatigue parameters for fretting fatigue life prediction. In this study, the fretting fatigue lift and critical location ware estimated and evaluated through the multiaxial fatigue theories in a cylinder-on-flat contact configuration far Cr-Mo steel, SCM420, the material commonly is used in gears of the automobile and rollers of the conveyor. The strain-life curve was obtained from fatigue test for SCM420. The Fretting fatigue life and critical location were estimated through stress distributions, SWT-parameters and FS-parameters obtained from FEA. This paper showed possibility of applying multiaxial fatigue theories to fretting fatigue lift prediction comparing predicted life with experimental results.
Quantitative Measurement of Out-of-plane Deformation Using Shearography
Chang, Ho-Seob ; Jung, Sung-Wook ; Kim, Kyoung-Suk ; Jung, Hyun-Chul ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 131~137
Electronic Speckle Pattern Interferometry(ESPI) is a common method for measuring out-of-plane deformation and in-plane deformation and applied for vibration analysis and strain/stress analysis. However, ESPI is sensitive to environmental disturbance, which provide the limitation of industrial application. On the other hand, Shearography based on shearing interferometer which is insensitive to vibration disturbance can directly measure the first derivative of out-of-plane deformation. In this paper a technique that extract out-of-plane deformation from results of shearography by numerical processing is proposed and measurement results of ESPI and Shearoraphy are compared quantitatively.
Fundamental Process Development for Bio-degradable Polymer Deposition and Fabrication of Post Surgical Anti-adhesion Barrier Using the Process
Park, Suk-Hee ; Kim, Hyo-Chan ; Kim, Taek-Gyoung ; Jung, Hyun-Jeong ; Park, Tae-Gwan ; Yang, Dong-Yol ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 138~146
Some biodegradable polymers and other materials such as hydrogels have shown the promising potential for surgical applications. Post surgical adhesion caused by the natural consequence of surgical wound healing results in repeated surgery and harmful effects. Recently, scientists have developed absorbable anti-adhesion barriers that can protect a tissue from adhesion in case they are in use; however, they are dissolved when no longer needed. Although these approaches have been attempted to fulfill the criteria for adhesion prevention, none can perfectly prevent adhesions in all situations. Overall, we developed a new method to fabricate an anti-adhesion membrane using biodegradable polymer and hydrogel. It employed a highly accurate three-dimensional positioning system with pressure-controlled syringe to deposit biopolymer solution. The pressure-activated microsyringe was equipped with fine-bore nozzles of various inner-diameters. This process allowed that inner and outer shapes could be controlled arbitrarily when it was applied to a surgical region with arbitrary shapes. In order to fulfill the properties of the ideal barriers f3r preventing postoperative adhesion, we adopted the pre-mentioned method combined with surface modification with the hydrogel coating by which anti-adhesion property was improved.
Photothermal and Photochemical Investigation on Laser Ablation of the Polyimide by 355nm UV Laser Processing
Oh, Jae-Yong ; Shin, Bo-Sung ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 147~152
UV laser ablation of polyimide is a combination of photochemical and photothermal mechanism. Photochemical mechanism is that molecular bonds are broken by photon energy and photothermal is evaporation and melt expulsion. When the laser processing, the etching depth needs to be calculated for prediction of processing result. In this paper, in order to predict the laser etching depth of polyimide by UV laser with the wavelength of 355nm, the theoretical model which includes both the photothermal and the photochemical effect was introduced. The model parameters were obtained by comparing with experimental results. The 3rd harmonic
laser system was used in the experiment. From these experimental and theoretical results, the laser ablation of a polyimide was verified to achieve the highest quality microstructure.
PDMS Stamp Fabrication for Photonic Crystal Waveguides
Oh, Seung-Hun ; Choi, Du-Seon ; Kim, Chang-Seok ; Jeong, Myung-Yung ;
Journal of the Korean Society for Precision Engineering, volume 24, issue 4, 2007, Pages 153~158
Recently nano imprint lithography to fabricate photonic crystal on polymer is preferred because of its simplicity and short process time and ease of precise manufacturing. But, the technique requires the precise mold as an imprinting tool for good replication. These molds are made of the silicon, nickel and quartz. But this is not desirable due to complex fabrication process, high cost. So, we describe a simple, precise and low cost method of fabricating PDMS stamp to make the photonic crystals. In order to fabricate the PDMS mold, we make the original pattern with designed hole array by finding the optimal electron beam writing condition. And then, we have tried to fabricate PDMS mold by the replica molding with ultrasonic vibration and pressure system. We have used the cleaning process to solve the detaching problem on the interface. Using these methods, we acquired the PDMS mold for photonic crystals with characteristics of a good replication. And the accuracy of replication shows below 1% in 440nm at diameter and in 610nm at lattice constant by dimensional analysis by SEM and AFM.