Go to the main menu
Skip to content
Go to bottom
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
Editor in Chief :
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
Chip on Glass Interconnection using Lateral Thermosonic Bonding Technology
Ha, Chang-Wan ; Yun, Won-Soo ; Park, Keum-Saeng ; Kim, Kyung-Soo ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 7~12
In this paper, chip-on-glass(COG) interconnection with anisotropic conductive film(ACF) using lateral thermosonic bonding technology is considered. In general, thermo-compression bonding which is used in practice for flip-chip bonding suffers from the low productivity due to the long bonding time. It will be shown that the bonding time can be improved by using lateral thermosonic bonding in which lateral ultrasonic vibration together with thermo-compression is utilized. By measuring the internal temperature of ACF, the fast curing of ACF thanks to lateral ultrasonic vibration will be verified. Moreover, to prove the reliability of the lateral thermosonic bonding, observation of pressured mark by conductive particles, shear test, and water absorption test will be conducted.
Dynamic Parameters Identification of an Air Spring for Vibration Isolation of a Complex Testing System of COG Bonding Process
Lee, Ju-Hong ; Kim, Pil-Kee ; Seok, Jong-Won ; Oh, Byung-Joon ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 13~20
Due to the recent quantum leaps forward in bio-, nano-, and information-technologies, the precisionization and miniaturization of mechanical and electrical components are in high demand. The allowable margin for vibration limits for such equipments is becoming stricter. In order to meet this demand, understandings on the characteristics of vibration isolation systems are highly required. Among the components comprising the vibration isolation system, air spring has become a focal point. In order to develop a complex defect tester for COG bonding of display panels, a vibration isolation system composed of air springs for mounting is considered in this study. The dynamic characteristics of the air spring are investigated, which is the most essential ingredient for reducing the vibration problem of the tester to the lowest level. Uncoupled dynamic parameters of the air spring are identified through MTS experiments, followed by suggestion of a model-based approach to obtain the remaining coupled dynamic parameters. Finally, the dynamic behaviors of the air spring are estimated and discussed.
The Effect of Bubble Generated during COG Bonding on the Joint Reliability
Choi, Eun-Soo ; Yun, Won-Soo ; Jeong, Young-Hun ; Kim, Bo-Sun ; Jin, Song-Wan ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 21~27
The effect of COG bonding parameters, especially the bonding temperature, on the bonding quality and reliability was investigated in this paper. We measured the bubble area formed in the ACF resin during the bonding process and tried to investigate the relationship between bubble area and bonding peel strength. 85/85 test which exposes a sample to a 85% humidity and
temperature condition was also carried out. The bubble area was dramatically increased under ~
lower than recommended bonding temperature. The bubble area formed at the edge of IC chip was larger than the other parts of IC chip. But the peel strength was not associated with the bubble area. High temperature and humid condition made the bubble area larger, but we could not find clear trend of change in the peel strength.
A Study on the Bonding Performance of COG Bonding Process
Choi, Young-Jae ; Nam, Sung-Ho ; Kim, Kyeong-Tae ; Yang, Keun-Hyuk ; Lee, Seok-Woo ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 28~35
In the display industry, COG bonding method is being applied to production of LCD panels that are used for mobile phones and monitors, and is one of the mounting methods optimized to compete with the trend of ultra small, ultra thin and low cost of display. In COG bonding process, electrical characteristics such as contact resistance, insulation property, etc and mechanical characteristics such as bonding strength, etc depend on properties of conductive particles and epoxy resin along with ACF materials used for COG by manufacturers. As the properties of such materials have close relation to optimization of bonding conditions such as temperature, pressure, time, etc in COG bonding process, it is requested to carry out an in-depth study on characteristics of COG bonding, based on which development of bonding process equipment shall be processed. In this study were analyzed the characteristics of COG bonding process, performed the analysis and reliability evaluation on electrical and mechanical characteristics of COG bonding using ACF to find optimum bonding conditions for ACF, and performed the experiment on bonding characteristics regarding fine pitch to understand the affection on finer pitch in COG bonding. It was found that it is difficult to find optimum conditions because it is more difficult to perform alignment as the pitch becomes finer, but only if alignment has been made, it becomes similar to optimum conditions in general COG bonding regardless of pitch intervals.
A Study on Stereo Vision-based Local Map Building and Path Generation for Obstacle Avoidance of the Hexapod Robot
Noh, Gyung-Gon ; Kim, Jin-Geol ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 36~48
This paper is concerned with stereo vision-based approach to detect obstacles and to generate the path of destination from the start. The hexapod robot in the experiment is cable of walking by legs and driving by wheels simultaneously. The hexapod robot operates under the driving mode normally, and it changes driving mode to walking mode to overcome obstacles using its legs. Disparity map, which is the correlation between two images taken by stereo camera, is employed for calculation of the distance between the robot and obstacles. When the obstacles information is extracted from the disparity map, the potential field algorithm is applied to create the obstacle-avoidance path. Simulator, based on OpenGL, is developed to generate the graphical path, and the experimental results are shown for the verification of the proposed algorithm.
A Study on the Dispersion Characteristics of Carbon Nanotubes using Cryogenic Ball Milling Process
Lee, Ji-Hoon ; Rhee, Kyong-Yop ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 49~54
The cryogenic ball milling was performed on carbon nanotubes (CNTs) at an extremely low temperature to increase the dispersion of CNTs. The effects of milling speed and time on the deagglomeration and structural changes of CNTs were studied. FESEM was used to analyze the dispersion and the change of particle size before and after milling process. Transmission electron microscopic (TEM) analysis was also investigated the effect of cryogenic ball milling on the morphological characteristics of CNTs. The structural changes by the cryogenic ball milling process were further confirmed by x-ray diffraction (XRD) and Raman spectroscopic analysis. The results showed that the agglomeration of CNTs was significantly reduced and amorphous structure was observed at high milling speed. However, the milling time has no great effect on the dispersion property and structural change of CNTs compared with milling speed.
A study on the Biped Walking Robot applying a Gravity Compensator
Choi, Hyeung-Sik ; Na, Won-Hyun ; Kim, Dong-Ho ; Chu, U-Heon ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 55~62
In this paper, the structure of a new gravity compensator was studied, and the biped walking robot applying a gravity compensator was presented to improve the performance of the robot. The robot had 13 degree of freedom and is driven by the joint actuator with the gravity compensator. Each leg of the robot is composed of six joints three joints at the hip, a joint at the knee, and two joints at the ankle. The leg of the robot was designed to support 74kg weight including 30kg payload thanks to the gravity compensator. The performance of the robot was presented by reducing the payload applied to the leg joint of the robot thanks to the gravity compensator.
Development of a Punching System for Pin-hole Type LED Display Board
Choi, Hyeung-Sik ; Kang, Jin-Il ; Her, Jae-Gwan ; Han, Jong-Suk ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 63~70
We developed a new punching system that generates pinholes expressing texts or images on a plastic plate. The pin-holed plate is used as a new glamorous display board reflecting colorful lights from the light emitting diode (LED) installed on the edge side of the plate. The four degree-of-freedom punching system was designed to make same multiple holes on four plastic plates simultaneously. For this motion, we designed a structure for a simultaneous motion of the system. For even reflection of the lights from texts or images on the board and fast production of the pin-holed boards, fast motion including precise position control is very important. We also built a PC-based integrated control system including a GUI program to help users easily design luminous texts or images on the plastic plate. Also, we conducted a performance test of the system to verify the punching speed and position control of the pin holes on the plate.
Electromagnetic Interference Shielding Effect of Fiber Reinforced Composites with Stainless Fiber Conductive Filler
Han, Gil-Young ; Song, Dong-Han ; Ahn, Dong-Gyu ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 71~78
The objective of this research is to investigate the influence of material characteristic and design on to the electromagnetic interference (EMI) shielding characteristics. Basalt glass fiber reinforced composite specimens with stainless fiber conductive filler were manufactured to perform the electromagnetic interference shielding effectiveness(SE) experiments. In order to reflection and absorb the specimen in electromagnetic fields, flanged coaxial transmission line sample holder was fabricated according to ASTM D 4935-89. Electromagnetic shielding effectiveness(EMSE) was measured quantitatively to examine the electromagnetic shielding characteristics of designed specimens. The result of EMI shielding experiments showed that maximum EMSE value of sandwich type specimens with GSG(basalt glass fiber/stainless fiber/basalt glass fiber) and SGS(stainless fiber/basalt glass fiber/stainless fiber) were 65dB and 80dB at a frequency of 1,500MHz, respectively.
A Study on Blasting for Paint Exfoliation on Plastic Coated Faces Using the Environment-Friendly Abrasive Materials of Starch Series
Li, Li-Hai ; Kim, Yeon-Sul ; Lee, Hi-Koan ; Yang, Gyun-Eui ; Mun, Sang-Don ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 79~86
The environment-friendly abrasive materials of starch series has a wide range of application value such as deburring of plastic injection products, paint exfoliation and surface treatment of painted products and polishing, etc. In this study, an experiment of paint exfoliation was performed by using the environment-friendly abrasive materials made of cheap starch, and its performance was reviewed. By adjusting the grit size of abrasive materials, nozzle pressure, nozzle feed and number of nozzle repetition, paint could be exfoliated effectively. In this experiment, it was found that the most suitable condition was grit size 0.75~1.0 mm, nozzle pressure 0.4 MPa, nozzle feed 5 mm/min and number of processing repetition 2 times.
Evaluation of Efficiency on Glass Precision Machining by using Abrasive Water-jet
Bahk, Yeon-Kyoung ; Park, Kang-Su ; Kim, Hyung-Hoon ; Shin, Bo-Sung ; Ko, Jong-Soo ; Go, Jeung-Sang ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 87~93
This paper presents an evaluation of efficiency on glass precision machining by using abrasive water-jet machine. In this study, problems of conventional water-jet machining are examined experimentally and are analysized numerically. Especially, the reason of whitening on the machined surface of biochip glass is determined. It is found that the mass flow rate of abrasive input and transverse speed of water-jet are key parameters to control the direct machining of micro hole and channel on a glass substrate. Based on results of experimental analysis, possibility of direct fabrication of micro holes and channels on a glass substrate is successfully confirmed.
Design and Evaluation of an Ultra Precision Rotary Table for Freeform Machine Tools
Hwang, Joo-Ho ; Park, Chun-Hong ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 94~100
This paper describes the design and evaluation procedure of an ultra-precision rotary table for freeform generating machined tools. Design of the thrust and journal hydrostatic bearings and experimental evaluation of the table were performed. To get the compact size and less lost motion direct drive servomotor with ultra precision encoder. From the considered design, following performance were confirmed by experiment. The total stiffness of the prototype rotary table was 483.6
for axial and radial direction, respectively. Rotational accuracy of the table was investigated by capacitive sensor and reversal measurement technique, and 0.10
radial direction and 0.05
axial direction of the rotational accuracy were confirmed. The micro resolution of the table was also investigated with displacement of capacitive sensor, and
of micro resolution was confirmed. Index accuracy of the table was evaluated by the autocollimator and polygon mirror, and the
arcsec accuracy and
arcsec repeatability of the table were confirmed. Those are under the general requirements of ultra precision rotary tables for freeform generating machined tools.
Premature Failure Prevention design of Three-way Catalyst Substrate using DOE
Lee, Dong-Woo ; Cho, Seok-Swoo ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 101~108
Domestic three-way catalyst satisfies exhaust gas conversion efficiency or pressure drop etc. but doesn't satisfy thermal durability. Thermal stress analysis for three-way catalyst was performed based on experimental temperature distribution. Thermal safety of three-way catalyst was estimated by safety factor. Aspect ratio variable had the most significant effect on thermal stress. Thickness variable had the least significant effect on thermal stress. Optimal conditions for premature failure prevention of three-way catalyst were as follows : (1) aspect ratio of three-way catalyst : 0.6:1 (2) 2.84mm thick (3) silicon nitride. The safety of Taguchi-optimized three-way catalyst were 4.7 times higher than that of existent three-way catalyst.
Contact-less Conveyance of Conductive Plate by Controlling Permalloy Sheet for Magnetic Shield of Air-gap Magnetic Field from Magnet Wheels
Jung, Kwang-Suk ; Shim, Ki-Bon ; Lee, Sang-Heon ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 109~116
The magnet wheel which generates on its interfacing conductive part a repulsive force and a traction torque by rotation of permanent magnets is used to manipulate the conductive plate without mechanical contact. Here, the air-gap magnetic field of the magnet wheel is shielded partially to convert the traction torque into a linear thrust force. Although a magnitude of the thrust force is constant under the fixed open region, we can change the direction of force by varying a position of the shield sheet. So, the spatial position of conductive plate is controlled by not the force magnitude from each magnet wheel but the open position of shield sheet. This paper discusses non-contact conveyance system of the conductive plate using electromagnetic forces from multiple magnet wheels.
A Study on Ultra Precision Grinding of Silicon Carbide Molding Core for High Pixel Camera Phone Module
Kim, Hyun-Uk ; Kim, Jeong-Ho ; Ohmori, Hitoshi ; Kwak, Tae-Soo ; Jeong, Shang-Hwa ;
Journal of the Korean Society for Precision Engineering, volume 27, issue 7, 2010, Pages 117~122
Recently, aspheric glass lens molding core is fabricated with tungsten carbide(WC). If molding core is fabricated with silicon carbide(SiC), SiC coating process, which must be carried out before the Diamond-Like Carbon(DLC) coating can be eliminated and thus, manufacturing time and cost can be reduced. Diamond Like Carbon(DLC) is being researched in various fields because of its high hardness, high elasticity, high durability, and chemical stability and is used extensively in several industrial fields. Especially, the DLC coating of the molding core surface used in the fabrication of a glass lens is an important technical field, which affects the improvement of the demolding performance between the lens and molding core during the molding process and the molding core lifetime. Because SiC is a material of high hardness and high brittleness, it can crack or chip during grinding. It is, however, widely used in many fields because of its superior mechanical properties. In this paper, the grinding condition for silicon carbide(SiC) was developed under the grinding condition of tungsten carbide. A silicon carbide molding core was fabricated under this grinding condition. The measurement results of the SiC molding core were as follows: PV of 0.155
(apheric surface) and 0.094
(plane surface), Ra of 5.3 nm(aspheric surface) and 5.5 nm(plane surface).