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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 28, Issue 12 - Dec 2011
Volume 28, Issue 11 - Nov 2011
Volume 28, Issue 10 - Oct 2011
Volume 28, Issue 9 - Sep 2011
Volume 28, Issue 8 - Aug 2011
Volume 28, Issue 7 - Jul 2011
Volume 28, Issue 6 - Jun 2011
Volume 28, Issue 5 - May 2011
Volume 28, Issue 4 - Apr 2011
Volume 28, Issue 3 - Mar 2011
Volume 28, Issue 2 - Feb 2011
Volume 28, Issue 1 - Jan 2011
Selecting the target year
Development of a Large Surface Mechanical Micro Machining System & Machine
Park, Chun-Hong ; Oh, Jeong-Seok ; Shim, Jong-Youp ; Hwang, Joo-Ho ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 761~768
The large surface micro machining system includes the equipments and processes for manufacturing the ultra precision micro patterned products with large surface through the mechanical machining. Recent major issue on the micro machining technology may be the development of optical parts for the back light unit of display which has the largest market. This special issue makes up with three parts; the large surface micro machining system and machine, machining process and forming process. In this paper, the state-of-the-art and core technology of large surface micro machining system is introduced with focus on the manufacturing technology for the back light unit of LCD TV. Then, some research results on the development of a roll die lathe is introduced which involves the concept of machine design, improvement of thermal characteristics in the spindle system, improvement of relative parallelism and straightness between spindle system and long stroke feed table, machining of micro pitch patterns. Finally, the direct forming process is introduced as the future work in the large surface micro machining field.
Core Technology Development for Micro Machining Process on Large Surface
Lee, Seok-Woo ; Lee, Dong-Yoon ; Song, Ki-Hyeong ; Kang, Ho-Chul ; Kim, Su-Jin ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 769~776
In order to cope with the requirements of smaller patterns, larger surfaces and lower costs in the fields of displays, optics and energy, greater attentions is now being paid to the development of micro-pattern machining technology. Compared with flat molds, roll molds have the advantages of short delivery, ease of manufacturing larger surfaces, and continuous molding. This paper presents the state-of-the-art of the micro pattern machining technology on the roll molds and introduces some research results on the machining process technology. The copper and nickel-phosphorous-alloy plating process, machining process technology for uniform micro patterns. micro cutting simulation and the real time monitoring system for micro machining are summarized. The developed technologies have led the complete localization of the prism sheets and will be applied to the direct forming process with succeeding research & development.
Development of Key Technologies for Large Area Forming of Micro Pattern
Choi, Doo-Sun ; Yoo, Yeong-Eun ; Yoon, Jae-Sung ; Je, Tae-Jin ; Park, Si-Hwan ; Lee, Woo-Il ; Kim, Bong-Gi ; Jeong, Eun-Jeong ; Kim, Jin-Sang ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 777~782
Micro features on the surface are well-known to have significant effects on optical or mechanical properties such as the optical interference, reflectance at the surface, contact angle, interfacial friction, etc. These surface micro features are increasingly employed to enhance the functionality of the applications in various application areas such as optical components for LCD or solar panel. Diverse surface features have been proposed and some of them are showing excellent efficiency or functionality, especially in optical applications. Most applications employing the micro features need manufacturing process for mass production and the injection molding and roll-to-roll forming, which are typical processes for mass production adopting polymeric materials, may be also preferred for micro patterned plastic product. Since the functionality or efficiency of the surface structures generally depends on the shape and the size of the structure itself or the array of the structures on the surface, it would be very important to replicate the features very precisely as being designed during the molding the micro pattern applications. In this paper, a series of research activities is introduced for roll-to-roll forming of micro patterned film including filling of patterns with UV curable resin, demolding of surface structures from the roll tool, control of surface energy and cure shrinkage of resin and dispose time and intensity of the UV light for curing of UV curable resin.
Zirconia Ceramic Powder Coating of Ti-6AI-4V by Laser Cladding
Kang, Kyung-Ho ; Kim, Jae-Do ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 783~788
The recent development of bio-ceramic material is being studied in various bio-material engineering field. There are lots of technical difficulties because manufacturing or bonding technique are required bio-friendliness, cleanliness and persistence. Zirconia ceramic powder is cladded on Ti-6AI-4V metallurgically by laser cladding processing. Laser cladding system with powder feeding delivery is designed and manufactured for optimum processing condition. Increasing of manufacturing speed and good quality of clad layer are achieved by application of preheating of substrate before laser cladding. The thin dilution and good clad layer on the substrate are obtained for applications of bio-materials such as the dental materials and the articulated joints of human body.
Compensating the Elliptical Trajectory of Elliptical Vibration Cutting Device
Loh, Byoung-Gook ; Kim, Gi-Dae ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 789~795
In elliptical vibration cutting (EVC), cutting performance is largely affected by the shape of an elliptical path of the cutting tool. In this study, two parallel piezoelectric actuators were used to make an elliptical vibration cutting device. When harmonic voltages of
out-of-phase are supplied to the EVC device, creation of an ideal elliptical trajectory whose major and minor axes are parallel to the cutting and thrust directions is anticipated from a kinematic analysis of the EVC device, however, the paths we experimentally observed showed significant distortions in its shape ranging from skew to excessive elongation of the major axis of the ellipse. To compensate distortions, an analytical model describing the elliptical path of the cutting tool was developed and verified with experimental results, and based on the analytical model, the distorted elliptical paths created at 100 Hz, 1 kHz, and 16 kHz were corrected for skew and elongation.
A Study on the Eigenmode Characteristics by Changing Damping Parameters of Secondary Suspension (Damper) on Railway Vehicles
Shin, Yu-Jeong ; You, Won-Hee ; Park, Joon-Hyuk ; Hur, Hyun-Moo ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 796~804
Railway vehicles are capable of indicating several types of instability. This phenomenon, which is called hunting motion, is a self excited lateral oscillation that is caused by the running velocity of the vehicle and wheel frail interactive forces. The interactive forces act to change effectively the damping characteristics of railway vehicle systems. This paper will show the impact of instability on the transfer function behavior using damping characteristics of secondary suspension. The vehicle dynamics are modeled using a 17 degree of freedom considering linear wheel/rail contact. The paper deals with certain condition of the damper characteristics that one is about various damping coefficient and another is equipped damper direction.
A Study on the Dynamic Stress Analysis of an Engine Block using Flexible-body Dynamic Analysis
Son, Chang-Su ; Cheon, Ho-Jeong ; Seong, Hwal-Gyeong ; Yoon, Keon-Sik ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 805~813
The dynamic stress of the diesel engine block is analyzed by using flexible-body dynamic analysis. Multiple loadings including the pressure load due to gas combustion, thermal load, and dynamic load are considered. Thermal load is assumed constant, however, pressure load and dynamic load are treated as time dependent. The present work is focused on the dynamic stress analysis, especially on finding critical points of the engine block. The analysis model includes four parts - engine block, generator, bed, and mounts. On the other hand, crank shaft, pistons, and main bearings are excluded from the model. However, their dynamic effects are applied by dynamic forces, obtained in the separate analysis. Dynamic stress is found by using flexible body dynamic analysis, and compared to the measured data.
Tension Estimation of Tire using Neural Networks and DOE
Lee, Dong-Woo ; Cho, Seok-Swoo ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 814~820
It takes long time in numerical simulation because structural design for tire requires the nonlinear material property. Neural networks has been widely studied to engineering design to reduce numerical computation time. The numbers of hidden layer, hidden layer neuron and training data have been considered as the structural design variables of neural networks. In application of neural networks to optimize design, there are a few studies about arrangement method of input layer neurons. To investigate the effect of input layer neuron arrangement on neural networks, the variables of tire contour design and tension in bead area were assigned to inputs and output for neural networks respectively. Design variables arrangement in input layer were determined by main effect analysis. The number of hidden layer, the number of hidden layer neuron and the number of training data and so on have been considered as the structural design variables of neural networks. In application to optimization design problem of neural networks, there are few studies about arrangement method of input layer neurons. To investigate the effect of arrangement of input neurons on neural network learning tire contour design parameters and tension in bead area were assigned to neural input and output respectively. Design variables arrangement in input layer was determined by main effect analysis.
Dynamical Mechanism Analysis of An Industrial Two-step Folding Automatic Door
Yun, Seong-Ho ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 821~826
This paper deals with an analysis of dynamic mechanism for the industrial two-step folding automatic door. A nonlinear equation of motion was derived in terms of folding angle to estimate driving forces. Based on this dynamic behavior, time taken during the door's opening well as their velocities were controlled so that the operating conditions can be obtained for the purpose of design. The stiffness of twisting spring was also investigated when the automatic door closed, because a dangerous accident takes place from the door's free falling. The current research will be a very useful tool in the near future for the dynamic analysis for the multi-step folding automatic door.
Development of Forming Technology for Clutch Gear Using Artificial Neural Network
Kang, Jae-Young ; Kim, Byung-Min ; Kim, Yeong-Hwan ; Kim, Dong-Hawn ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 827~833
Precision forging of gears has a lot of advantages when compared to conventional gear shaping, because it allows the manufacture of gear parts without flash and consequently without the need for subsequent machining operations. In this study, the cold forging process is determined to manufacture the cold forged product for the precision clutch gear used of a commercial automobile, To do this, shape ratio of initial shape having influence the forgeability of forged product is analyzed. The optimal initial shape of clutch gear is designed using the results of DEFORM-3D and the artificial neural network (ANN). The initial shape through the detail analysis results, such as metal flow, distributions of strain can be obtained.
Computer-aided Design and Fabrication of Bio-mimetic Scaffold for Tissue Engineering Using the Triply Periodic Minimal Surface
Yoo, Dong-Jin ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 834~850
In this paper, a novel tissue engineering scaffold design method based on triply periodic minimal surface (TPMS) is proposed. After generating the hexahedral elements for a 3D anatomical shape using the distance field algorithm, the unit cell libraries composed of triply periodic minimal surfaces are mapped into the subdivided hexahedral elements using the shape function widely used in the finite element method. In addition, a heterogeneous implicit solid representation method is introduced to design a 3D (Three-dimensional) bio-mimetic scaffold for tissue engineering from a sequence of computed tomography (CT) medical image data. CT image of a human spine bone is used as the case study for designing a 3D bio-mimetic scaffold model from CT image data.
Modularized Flexure-Hinge Nanopositioner Based on Four-Bar-Link-Mechanism
Chae, Ki-Woon ; Bae, Jin-Hyun ; Jeong, Young-Hun ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 851~858
Nanopositioning technologies play an important role in the progress of electronics, optics, bio-engineering and various nano-scale technologies. As a result, various practical nanopositioning methods have been successfully introduced. Flexure mechanism is a valuable method in nanopositioning because of smooth and friction-free motion and the infinitesimal movement near to sub-nm. In this study a modularized nanopositioner based on parallelogram four-bar linkage structure with right-circular flexure hinge was developed. The positioning performance of a single axis nanopositioner and a XY nanopositioner which was extended from single axis one were demonstrated using control experiments. Consequently, it was shown that the developed single axis nanopositioner possessed high performance and could be extended to various multi-axis nanopositioners.
Development of Bio-Check Unit and Health Index for Measuring Health Degree through Noninvasive Examination
Lee, Chong-Sun ; Yi, Sung-Il ; So, Byung-Rok ; Park, Byung-Kang ; Chung, In-Wook ; Lee, Seung-Ju ; Park, Seon-Kyun ; Han, Cheng-En ;
Journal of the Korean Society for Precision Engineering, volume 28, issue 7, 2011, Pages 859~865
A bio-check unit and health index were developed to provide information on personal health state with easily available noninvasive measurements and surveys. Four health indices were defined such as cardiovascular index, stress index, obesity index, and management index. Methods were developed to calculate health index scores from measured physiological signals and answer of survey questions. In order to evaluate effectiveness of the health indices, a clinical trial was conducted for 362 persons who visited general hospital for annual health inspection. The cardiovascular index showed a good correlation coefficient of 0.685 with the cardiovascular health graded by a medical doctor. The stress index showed a good correlation coefficient of 0.638 with the results of stress questionnaires being used in the public health center. Once the health index function is added in the bio-check unit, the unit may provide useful contents for personal health management.