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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
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 26, Issue 12 - Dec 2009
Volume 26, Issue 11 - Nov 2009
Volume 26, Issue 10 - Oct 2009
Volume 26, Issue 9 - Sep 2009
Volume 26, Issue 8 - Aug 2009
Volume 26, Issue 7 - Jul 2009
Volume 26, Issue 6 - Jun 2009
Volume 26, Issue 5 - May 2009
Volume 26, Issue 4 - Apr 2009
Volume 26, Issue 3 - Mar 2009
Volume 26, Issue 2 - Feb 2009
Volume 26, Issue 1 - Jan 2009
Selecting the target year
Electron Beam Lithography and Nano Imprint Lithography for High-Efficiency Optical Devices
Cho, Sang-Uk ; Oh, Seung-Hun ; Kim, Chang-Seok ; Jeong, Myung-Yung ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 7~13
Fabrication of Monolithic Dual-scale Structure by Advanced Multi-step Capillary Force Lithography (CFL)
Suh, Kahp-Yang ; Kwak, Rho-Kyun ; Jeong, Hoon-Eui ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 14~20
Technology for the Multi-layer Nanoimprint Lithography Equipments
Lee, Jae-Jong ; Choi, Kee-Bong ; Kim, Gee-Hong ; Park, Soo-Yeon ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 21~25
Duplication of Nanostructures Using Transparent Hot Embossed Polymer Stamp
Lee, Heon ; Hong, Sung-Hoon ; Byeon, Kyeong-Jae ; Han, Kang-Soo ; Shin, Ju-Hyson ; Yang, Ki-Yeon ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 26~29
Nano Replication Technology of Nano Patterns and Application Fields
Han, Jeong-Won ; Choi, Jun-Hyuk ; Yoo, Yeong-Eun ; Kim, Byeong-Hee ; Lee, Jae-Sook ; Kang, Shin-Ill ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 30~35
Femtosecond Laser Lithography for Maskless PR Patterning
Sohn, Ik-Bu ; Ko, Myeong-Jin ; Kim, Young Seop ; Noh, Young-Chul ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 36~40
Development of maskless lithography techniques can provide a potential solution for the photomask cost issue. Furthermore, it could open a market for small scale manufacturing applications. Since femtosecond lasers have been found suitable for processing of a wide range of materials with sub-micrometer resolution, it is attractive to use this technique for maskless lithography. As a femtosecond laser has recently been developed, both of high power and high photon density are easily obtained. The high photon density results in photopolymerization of photoresist whose absorption spectrum is shorter than that of the femtosecond laser. The maskless lithography using the two-photon absorption (TPA) makes micro structures. In this paper, we present a femtosecond laser direct write lithography for submicron PR patterning, which show great potential for future application.
Ultra-precision Cutting of Polycarbonate for Optical Components by Using Elliptical Vibration Cutting Method
Song, Young-Chan ; Park, Chun-Hong ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 42~49
The optical elements made of plastics are normally produced by mass production such as injection molding with use of precision dies and molds. It costs to prepare the dies and molds, and it is only justified to prepare such expensive dies and molds when the parts are massively produced. On the other hand, it is too expensive and inefficient when precision plastic parts are needed only in small quantities, such as a case of trial manufacturing of new products. An ultra-precision diamond cutting is one of promising processes to produce the precision plastic parts in such cases. But it is commonly believed that an ultra-precision cutting of plastics for optical components is very difficult, because they are thermo-plastic material. In the present research, an ultra-precision diamond cutting of polycarbonate (PC), that is one of typical optical materials, was tried by using elliptical vibration cutting method. It is experimentally proved that good optical surfaces were obtained by using elliptical vibration cutting in cases of grooving and flat surfaces. The maximum surface roughness of less than 60 nm in peak to valley value is acquired.
Autofocus system for off-line focusing error compensation in micro laser fabrication process
Kim, Sang-In ; Kim, Ho-Sang ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 50~58
Micro laser fabrication techniques can potentially be used for the manufacture of microstructures on the thin flat surfaces with large diameter that are frequently used in semiconductor industries. However, the large size of wafers can cause the degraded machining accuracy of the surface because it can be tilted or distorted by geometric errors of machines or the holding fixtures, etc. To overcome these errors the off-line focusing error compensation method is proposed. By using confocal autofocus system, the focusing error profile of machined surface is measured along the pre-determined path and can be compensated at the next machining process by making the corrected motion trajectories. The experimental results for silicon wafers and invar flat surfaces show that the proposed method can compensate the focusing error within the level of below
that is the depth of focus required for the laser micromachining process.
Gaits Control for Skating Motion with Nonholonomic Constraint
Hwang, Chang-Soon ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 59~67
This paper addresses the control method for skating motion with a nonholonomic constraint. In order to generate a human-like skating motion, the behaviors of motion are distinctively analyzed into transient state and steady state. A close investigation of the behaviors evolved the characteristic of successive motions with transient state and steady state. Simulation results were intuitively comprehensible, and the effectiveness of control method was demonstrated for skating motion.
Study on Modeling and Experiment of Optical Three Axis Tool-Origin Sensor for Applications of Micro Machine-Tools
Shin, Woo-Cheol ; Lee, Hyeon-Hwa ; Ro, Seung-Kook ; Park, Jong-Kweon ; Noh, Myoung-Gyu ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 68~73
One of the traditional optical methods to monitor a tool is a CCD sensor-based vision system which captures an aspect of the tool in real time. In the case using the CCD sensor, specific lens-modules are necessary to monitor the tool with higher resolution than its pixel size, and a microprocessor is required to attain desired data from captured images. Thus theses additional devices make the entire measurement system complex. Another method is to use a pair of an optical source and a detector per measuring axis. Since the method is based on the intensity modulation, the structure of the measurement system is simper than the CCD sensor-based vision system. However, in the case measuring the three dimensional position of the tool, it is difficult to apply to micro machine-tools because there may not be space to integrate three pairs of an optical source and a detector. In this paper, in order to develop a tool-origin measurement system which is employed in micro machine-tools, the improved method to measure a tool origin in x, y and z axes is introduced. The method is based on the intensity modulation and employs one pair of an optical source radiating divergent beams and a quadrant photodiode to detect a three dimensional position of the tool. This paper presents the measurement models of the proposed tool-origin sensor. The models were verified experimentally The verification results show that the proposed method is possible and the induced models are available for design.
Autonomous Traveling of Unmanned Golf-Car using GPS and Vision system
Jung, Byeong Mook ; Yeo, In-Joo ; Cho, Che-Seung ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 74~80
Path tracking of unmanned vehicle is a basis of autonomous driving and navigation. For the path tracking, it is very important to find the exact position of a vehicle. GPS is used to get the position of vehicle and a direction sensor and a velocity sensor is used to compensate the position error of GPS. To detect path lines in a road image, the bird's eye view transform is employed, which makes it easy to design a lateral control algorithm simply than from the perspective view of image. Because the driving speed of vehicle should be decreased at a curved lane and crossroads, so we suggest the speed control algorithm used GPS and image data. The control algorithm is simulated and experimented from the basis of expert driver's knowledge data. In the experiments, the results show that bird's eye view transform are good for the steering control and a speed control algorithm also shows a stability in real driving.
Matching Design of a Tension Controller with Pendulum Dancer in Roll-to-Roll Systems
Kang, Hyun-Kyoo ; Shin, Kee-Hyun ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 81~89
Dancer systems are typical equipment for attenuation of tension disturbances. Lately, demands for high speed roll-to-roll machines are rising but it is prior to attenuate the tension variation on the web entering into the printing zone to achieve the speed increment. Maintaining a constant tension before the first printing cylinder is the key of high speed, high quality printing. Dancer has been researched in two ways, whether it is controlled or not. The first one is active dancer and the other one is passive dancer. In the active dancer, a position of idle roll of dancer is measured and the roll is moved by external hydraulic cylinder to control tension disturbances. While the passive one composed with spring, damper and idle roll has no external actuator to position the idle roll. The tension disturbance causes movement of dancer roll and the displacement of the roll regulates the tension variation. On the other hand a composite type of dancer is applied for roll-to-roll printing machines. It has same apparatus as passive dancer. The displacement of roll is measured and front(or rear) driven roller is controlled to position the roll. In this paper, it is presented an analysis of pendulum dancer including position feedback PI control and logic for PI gain tuning in roll-to-roll machines. Pole-zero map and root locus with varying system parameters gives a design method for control of the dancer.
The Prediction of Fatigue Damage for Pressure Vessel Materials using Shear Horizontal Ultrasonic Wave
Kang, Yong-Ho ; Chung, Yong-Keun ; Song, Jung-Il ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 90~96
Ultrasonic method using SH(shear horizontal) wave has been developed to determine the surface damage in fatigued material. Fatigue damages based on propagation energy were analyzed by multi-regression analysis in interrupted fatigue test specimen including CrMoV and 12Cr alloy steel. From the test results, as the fatigue damage increased the propagation time of the launched waves increased and amplitude of wavelet decreased. Also, analysis for the waveform modulation showed a reliable estimation, with confidence limit of 97% for 12Cr steel and 95% for CrMoV steel, respectively. Therefore, It is thought that SH ultrasonic wave technique can be applied to determine fatigue damage of in-service component nondestructively.
Design of a Roller Rail for the Drawer of Three-Door Refrigerators Using Taguchi Method
Lee, Boo-Youn ; Kim, Je-Hyun ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 97~105
Optimal design of a roller rail which replaces the ball rail for three-door refrigerators is presented using the finite element analysis and the Taguchi method. Stress and deformation of the roller rail for an initial design are analyzed and evaluated. Optimal design parameters are determined using the Taguchi method. The maximum stress of the optimal design is favorably reduced comparing to the initial design. It is verified through an additional analysis that the drawer on the roller rail will not be derailed even if one opens the drawer with a transverse force.
Design and Modeling of a 6-dof Stage for Ultra-Precision Positioning
Moon, Jun-Hee ; Park, Jong-Ho ; Pahk, Heui-Jae ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 106~113
A 6-DOF precision stage was developed based on parallel kinematics structure with flexure hinges to eliminate backlash, stick-slip and friction and to minimize parasitic motion coupled with motions in the other-axis directions. For the stage, lever linkage mechanism was devised to reduce the height of system for the enhancement of horizontal stiffness. Frequency response comparison between experimental results and mathematical model extracted from dynamics of the stage was performed to identify the system parameters such as spring constants and damping coefficients of actuation modules, which cannot be calculated accurately by analytic methods owing to their complicated structures. This newly developed precision stage and its identified model will be very useful for precision positioning and control because of its high accuracy and non-coupled movement.
Development of New Electroplating Alloy (Au-Cu) for Increasing the Durability of PCB Commutator in Vibration Motor
Kim, Young-Tae ; Lee, Sung-Jae ; Park, Sung-Jun ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 114~121
Mobile phone is a representative personal communication tool among wireless communication devices. Recently, with the miniaturization and light-weight trend of mobile phone, the vibration motor has been replaced by coin type. The required performances of coin type vibration motor needed by user are long life, higher vibration, and thin thickness. Also the most important factor determines the performance of vibration motor is long-term reliability, which is mainly related to PCB plating technique for commutator. In this study, three types of fault were categorized to analyze the cause for malfunction of vibration motor. And, hardness and surface morphology on plating surface are also investigated to optimize the plating method and plating conditions. As a result, new plating method and conditions were proposed to increase the durability of PCB commutator.
Estimation of Muscle-tendon Model Parameters Based on a Numeric Optimization
Nam, Yoon-Su ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 122~130
The analysis of human movement requires the knowledge of the Hill type muscle parameters, the muscle-tendon and moment arm length change as a function of joint angles. However, values of a subject's muscle parameters are very difficult to identify. It turns out from a sensitivity analysis that the tendon slack length and maximum muscle force are the two critical parameters among the Hill-type muscle model. Therefore, it could be claimed that the variation of the tendon slack length and maximum muscle force from the Delp's reference data will change the muscle characteristics of a subject remarkably. A numeric optimization method to search these tendon parameters specific to a subject is proposed, and the accuracy of the developed algorithm is evaluated through a numerical simulation.
The Mechanical Properties of Trabecular Bone in Knee Joint
Kwak, Dai-Soon ; Oh, Taek-Yul ; Han, Seung-Ho ;
Journal of the Korean Society for Precision Engineering, volume 26, issue 6, 2009, Pages 131~135
In this study, we performed the compressive strength test of trabecular bone in knee joint for measuring the elastic modulus and ultimate strength. The main knee joint is femorotibial articulation between the lateral and medial femorotibial condyle. In the case of osteoarthritis, some patients have only medial condylar osteoarthritis. We performed the mechanical test for comparison the difference of the each condylar strength. We used diamond core-drill and linear precision saw for making the specimens. Specimens were cored from both condyle in distal femur and proximal tibia in fresh cadaver (male 10, female 12), and tested by universal test machine with temperature control saline circulation system. Results of the test in distal femoral parts, averaged elastic modulus was
for female. Averaged ultimate strength was
for female. Male was 2.4 times stronger than female. In the proximal tibial parts, averaged elastic modulus was
for female. Averaged ultimate strength was
for female. Male was 1.5 times stronger than female. In the distal femoral condyle, medial condyle had more strength than lateral condyle at middle region. But lateral condyle had more strength than medial condyle at anterior & posterior regions (p<0.02). In the proximal tibial condyle, medial condyle had more strength than lateral condyle. (p<0.01).