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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
Editor in Chief :
Volume & Issues
Volume 29, Issue 12 - Dec 2012
Volume 29, Issue 11 - Nov 2012
Volume 29, Issue 10 - Oct 2012
Volume 29, Issue 9 - Sep 2012
Volume 29, Issue 8 - Aug 2012
Volume 29, Issue 7 - Jul 2012
Volume 29, Issue 6 - Jun 2012
Volume 29, Issue 5 - May 2012
Volume 29, Issue 4 - Apr 2012
Volume 29, Issue 3 - Mar 2012
Volume 29, Issue 2 - Feb 2012
Volume 29, Issue 1 - Jan 2012
Selecting the target year
Study on Ultra-precision Grinding of EL-Max Material for Hot Press Molding
Park, Soon Sub ; Ko, Myeong Jin ; Kim, Geon Hee ; Won, Jong Ho ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1267~1271
DOI : 10.7736/KSPE.2012.29.12.1267
Demand for optical glass device used for lighting could increase rapidly because of LED lighting market growth. The optical glass devices that have been formed by hot press molding process the desired optical performance without being subjected to mechanical processing such as curve generation or grinding. EL-Max material has been used for many engineering applications because of their high wear resistance, high compressive strength, corrosion resistant and very good dimensional stability. EL-Max is very useful for a glass lens mold especially at high temperature and pressure. The performance and reliability of optical components are strongly influenced by the surface damage of EL-Max during grinding process. Therefore, the severe process condition optimization shall be necessary for the highly qualified EL-Max glass lens mold. To get the required qualified surface of EL-Max, the selection of type of the diamond wheel is also important. In this paper, we report best grinding conditions of ultra-precision grinding machining. The grinding machining results of the form accuracy and surface roughness have been analyzed by using Form Talysurf and NanoScan.
Study on Machining High-Aspect Ratio Micro Barrier Rib Array Structures using Orthogonal Cutting Method
Park, Eun-Suk ; Choi, Hwan-Jin ; Kim, Han-Hee ; Jeon, Eun-Chae ; Je, Tae-Jin ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1272~1278
DOI : 10.7736/KSPE.2012.29.12.1272
The micro barrier rip array structures have been applied in a variety of areas including as privacy films, micro heat sinks, touch panel and optical waveguide. The increased aspect ratio (AR) of barrier rip array structures is required in order to increase the efficiency and performance of these products. There are several problems such as burr, defect of surface roughness and deformation and breakage of barrier rip structure with machining high-aspect ratio micro barrier rip array structure using orthogonal cutting method. It is essential to develop technological methods to solve these problems. The optimum machining conditions for machining micro barrier rip array structures having high-aspect ratio were determined according to lengths (
) and shape angles (
) of diamond tool, overlapped cutting depths (
), feed rates (100 mm/s) and three machining processes. Based on the optimum machining conditions, micro barrier rib array structures having aspect ratio 30 was machined in this study.
Analysis of Micro Machining Characteristics using End-milling and Its Applications
Choi, Hwan-Jin ; Park, Eun-Suk ; Jeon, Eun-Chae ; Je, Tae-Jin ; Choi, Doo-Sun ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1279~1284
DOI : 10.7736/KSPE.2012.29.12.1279
Micro structures which are widely used at various fields are commonly fabricated by lithograph, etching and laser methods. Recently, with the emergence of micro tools and ultra-precision machine tools, fabrication of the micro structures obtained using end-milling are studied. However, there are some problems due to the diameter of the micro end-mill getting smaller below
. The micro run-out resulted from miniaturization of end-mills have influence seriously on accuracy of micro structures. The error of run-out with a tooling jig showed a decrease of about
. Furthermore, micro structures with width of
could be applied through experiments of slot machining obtained using 30 and
end-mill. Also, narrow angle structures with
angle could be applied through analysis of machining acute angle structures. Based on basic experiments, micro fluidics channels and spiral patterns for air bearing were machined.
A Study on Characteristics of ELID Lapping for Sapphire Wafer Material
Kwak, Tae-Soo ; Han, Tae-Sung ; Jung, Myung-Won ; Kim, Yunji ; Uehara, Yosihiro ; Ohmori, Hitoshi ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1285~1289
DOI : 10.7736/KSPE.2012.29.12.1285
This study has been focused on application of ELID lapping process for mirror-surface machining of sapphire wafer. Sapphire wafer is a superior material with optic properties of high performance as light transmission, thermal conductivity, hardness and so on. High effective surface machining technology is necessary to use sapphire as various usages. The interval ELID lapping process has been set up for lapping of the sapphire material. According to the ELID lapping experimental results, it shows that 12.5 kg of load for lapping is most pertinent to ELID lapping. the surface of sapphire can be eliminated by metal bonded wheel with micron abrasives and the surface roughness of 60 nmRa can be gotten using grinding wheel of 2,000 mesh in 4.5 um, depth of cut. In this study, the chemical experiments after ELID grinding also has been conducted to check chemical reaction between workpiece and grinding wheel on ELID grinding process. It shows that the chemical reaction has not happened as the results of the chemical experiments.
Design of Myopic Aspherical Ophthalmic Lenses with Peripheral Clear Vision and Properties of Its Ultra-Precision Machining
Kim, Dong-Ik ; Huh, Myeng-Sang ; Lee, Gil-Jae ; Park, Soon-Sub ; Won, Jong Ho ; Kim, Geon Hee ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1290~1295
DOI : 10.7736/KSPE.2012.29.12.1290
Oblique astigmatism according to the rotation of the eye has to be removed for obtaining peripheral clear vision in ophthalmic lenses. For this reason, we calculated tangential and sagittal power using third-order approximation theory and then controlled conic constant for the difference of the two powers to converge to 0 regardless of the rotation angle of the eye. As a result, an aspherical ophthalmic lens without oblique astigmatism was designed. Also, we found optimal machining condition to the lens material using factorial design and finally fabricated the designed lens through ultra-precision machining with that condition.
The Study on Dynamic Analysis of Durability of a Wheel using CAE
Park, Jae Heung ; Park, Tae Won ; Jung, Sung Pil ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1296~1303
DOI : 10.7736/KSPE.2012.29.12.1296
There is a certain limit to reproduce phenomena between the real vehicle and road, since the existing methods to verify durability of the wheel are mostly uni-axial tests. And the change of durability of the wheel can`t be predicted since these tests don`t consider the camber angle and lateral force as important factors. In this paper, the FE models of the wheel-tire and drum are created. Then, the vertical and lateral loads are applied to wheel-tire assembly and the camber angle is applied by inclining the wheel-tire assembly to the drum. Based on the analysis result, the crack position is predicted to be created in the body of the wheel. The variation of the stress according to the camber angle is verified and the maximum spot of the stress changes continually.
A Study on the Energy Management Control of Hybrid Excavator
Yoo, Bong Soo ; Hwang, Cheol Min ; Joh, Joongseon ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1304~1312
DOI : 10.7736/KSPE.2012.29.12.1304
According to the successful development of hybrid vehicle, hybridization of construction equipments like excavator, wheel loader, and backhoe etc., is gaining increasing attention. However, hybridization of excavator and commercial vehicle is very different. Therefore a specialized energy management control algorithm for excavator should be developed. In this paper, hybridization of excavators is investigated and a new energy management control algorithm is proposed. Four control parameters, i.e., lower baseline, upper baseline, idling generation speed, and idling generation torque, are newly introduced and a new operating principle using those four control parameters is proposed. The use of Genetic Algorithm for the optimization of the four control parameters from the view point of minimization of fuel consumption for standard excavating operation is suggested. In order to verify the proposed algorithm, dedicated simulation program of hybrid excavator was developed. The proposed algorithm is applied to a specific hydraulic excavator and 20.7% improvement of fuel consumption is achieved.
A Study on Health Monitoring of a Refrigerator Compressor Based on Higher Order Time-Frequency Analysis and Artificial Neural Network
Shin, Tae-Jin ; Lee, Sang-Kwon ; Jang, Ji Uk ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1313~1320
DOI : 10.7736/KSPE.2012.29.12.1313
Condition monitoring of the reciprocating compressor is important task. As a traditional method, health monitoring system of refrigerator depends on decision of a skilled person based on his experience. However, the skilled person cannot monitor all the compressors completely. If a sampled compressor is faulty, thousands of compressors manufactured at that place are regarded as faulty compressors. Therefore it is necessary to monitor all compressors in the production line. In the paper real time health monitoring system is developed based on high order time frequency method and artificial neural network. The system is installed in the mass production line. The result of the application has been very successful, and currently the system is working very well on the production line.
An Advanced Path Planning of Clustered Multiple Robots Based on Flexible Formation
Wee, Sung Gil ; Saitov, Dilshat ; Choi, Kyung Sik ; Lee, Suk Gyu ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1321~1330
DOI : 10.7736/KSPE.2012.29.12.1321
This paper describes an advanced formation algorithm of clustered multiple robots for their navigation using flexible formation method for collision avoidance under static environment like narrow corridors. A group of clustered multiple robots finds the lowest path cost for navigation by changing its formation. The suggested flexible method of formation transforms the basic group of mobile robots into specific form when it is confronted by particular geographic feature. In addition, the proposed method suggests to choose a leader robot of the group for the obstacle avoidance and path planning. Firstly, the group of robots forms basic shapes such as triangle, square, pentagon and etc. depending on number of robots. Secondly, the closest to the target location robot is chosen as a leader robot. The chosen leader robot uses
for reaching the goal location. The proposed approach improves autonomous formation characteristics and performance of all system.
Structural Capability Evaluation of the Conventional and Pilot Type Valves for LNG/LNG-FPSO Ships
Hwang, Dong Wook ; Kim, Sung Jin ; Bae, Jun Ho ; Jung, Sung Yuen ; Kim, Chul ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1331~1339
DOI : 10.7736/KSPE.2012.29.12.1331
Safety valve used in LNG/LNG-FPSO ships is a high value valve, and it plays an important role in maintaining a fixed level of pressure by emitting LNG gas out of pipes in LNG piping system under the cryogenic and high-pressure condition when the pressure of the system connected with the LNG storage tank and pipes reaches over the set pressure. The structural stability is required for the inner pressure and thermal load because of the cryogenic and high-pressure condition, and a reliability of the safety valve is necessary for impact and deformation by opening the valve. But, the safety valve, which plays a key role for a safety of the transport and storage system, is depended on imports for over 90%, and in domestic production, the design of the valve is performed on the basis of experiences of the works without quantitative analysis for the inner operation characteristics and structural stability of the valve. In this study, impact velocity is calculated by theoretical analysis for obtaining the structural stability of the guide according to the impact load by opening the valve. The shape of the guide and the diaphragm for satisfying the structural stability are suggested and verified by using a thermal-structural analysis.
Development of Speed Limit Safety Wheel used by Trochoid Gear
Lee, Dongkeun ; Lee, Siyoung ; Hong, Youngjun ; Koo, Jae-Mean ; Seok, Chang-Sung ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1340~1345
DOI : 10.7736/KSPE.2012.29.12.1340
Industrial products developed in recent years have focused on usability and stability. Especially, for the products used in daily life, steady efforts have been made to secure the safety. Among them, the products equipped with wheels such as strollers, shopping carts, and carriers can occur the safety accidents by unintended over speed at a ramp. Therefore, development of speed limit device is required to prevent such accidents. However, the existing speed limit devices are very expensive and have a complex drive principle, so it`s generally difficult to apply them. In this study, a simple speed limit wheel is suggested which can replace the previous complex and inconvenient speed limit devices. The developed speed limit wheel can be simply applied to existing products by changing the wheels. In addition, it has an advantage to operate only by mechanical mechanism without power supply. Thus it can minimize the cost and waste of resources. For this purpose, the operating condition of the target products was analyzed, and trochoid gear mechanisms were selected for the speed limit. Based on this, finite element analysis was conducted to estimate the operating mechanism. After the prototype of the wheel was produced, the performance under various conditions was tested and has been improved.
Bending Fatigue Life Evaluation of Pure Copper and Copper Alloy Contact Wire
Kim, Yongseok ; Li, Haochuang ; Kang, Minsung ; Koo, Jae-Mean ; Seok, Chang-Sung ; Lee, Kiwon ; Kwon, Sam-Young ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1346~1350
DOI : 10.7736/KSPE.2012.29.12.1346
Contact wire is one of the most important components supplying electricity to railroad cars. At the beginning of the research on contact wire, wear problem caused by friction between contact wire and pantograph was considered even more important issue for the failure of contact wire. However, since several fatigue fractures were reported from Shinkansen in Japan, fatigue fracture has become another important issue for the failure of contact wire. Despite of its importance, standard of the fatigue test of contact wire has not been established yet. Thus, fatigue characteristics of contact wire is very difficult issue to evaluate quantitatively. Hence, in this study, test method simulating operating conditions of contact wire by Minsung Kang and etc. is used to evaluate the fatigue characteristics of copper alloy contact wire. Also, test results is compared with the result of Minsung Kang`s research on pure copper contact wire.
Numerical Study on Evaluation of Design Parameters of Intermediate Shaft in Steering System
Kang, Young Su ; Doo, Min Soo ; Kim, Jeong ; Kang, Beom Soo ; Song, Woo Jin ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1351~1359
DOI : 10.7736/KSPE.2012.29.12.1351
Due to the development of electric and hybrid vehicles, the trend has changed from hydraulic power steering system to electric power steering system (EPS). In this paper, design parameters are deduced through the structural analysis based on the finite element analysis for the intermediate shaft of the EPS on the market. By analyzing the design parameters, the structure design is improved to support the required high torque on the EPS. The numerical analysis is performed to obtain the improved design of the intermediate shaft model and the analysis results are compared with the existing model. It is noted through this numerical approach that the improved design of the intermediate shaft can be acquired the structural safety and high stiffness than existing model.
A Study on Improvement of Bending Quality of Hemmed Plates in Sheet Metal Forming
Kim, Pan Gun ; Park, Sang Hu ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1360~1367
DOI : 10.7736/KSPE.2012.29.12.1360
A bending process is considered as one of fundamental sheet metal forming processes, and it is widely used for fabrication of simple or complicated sheet metal products in industrial fields. Most of automobiles and electronics have many parts made by the bending process inside or outside of them. However, till now, there is few research reports on the bending process of hemmed plates. A hemmed plate has a locally different bending strength, so a waving shape occurs after bending. A poor outlook due to local uneven shape influences greatly on product competitiveness. To settle this problem, we studied the bending parameters of a hemmed plate and showed the major sensitive design-parameters on the bending quality.
Roll Profile Design Considering Spread in Shape Rolling of Angle Bar by FE-analysis and Response Surface Method
Lee, Sang Jin ; Ko, Dae Cheol ; Lee, Sang Kon ; Kim, Byung Min ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1368~1375
DOI : 10.7736/KSPE.2012.29.12.1368
In this paper, a method for prediction of spread is proposed to design proper roll profile taking into account spread in shape rolling of angle bar. The effect of the process variables on spread, such as draught ratio, bending angle and aspect ratio, is analyzed by FE-analysis and response surface method (RSM). Roll profiles for equal angle bar are designed with the spread predicted by the regression equation. Effectiveness of the designed roll profiles are verified by FE-analysis in which the flange length, strain distribution, mean strain and roll torque are compared with those by Geuze. Finally, the proposed method is applied to the design of roll profile for unequal angle bar. As a result, the final product can be obtained within the allowable tolerance of
in length. Therefore, it is found that the prediction of spread can improve the efficiency of design roll profile in shape rolling of angle bar.
A Study on the Imprinting Process for an Optical Interconnection of PLC Device
Kim, Young Sub ; Cho, Sang Uk ; Kang, Ho Ju ; Jeong, Myung Yung ;
Journal of the Korean Society for Precision Engineering, volume 29, issue 12, 2012, Pages 1376~1381
DOI : 10.7736/KSPE.2012.29.12.1376
Optical devices are used extensively in the field of information network. Increasing demand for optical device, optical interconnection has been a important issue for commercialization. However many problems exist in the interconnection between optical device and optical fiber, and in the case of the multi-channel, problems of the optical alignment and optical array arise. For solving the alignment and array problem of optical device and the optical fiber, we fabricated fiber alignment and array by using imprint technology. Achieved higher precision of optical fiber alignment and array due to fabricating using imprint technology. The silicon stamp with different depth was fabricated using the conventional photolithography. Using the silicon stamp, a nickel stamp was fabricated by electroforming process. We conducted imprint process using the nickel stamp with different depth. The optical alignment and array by fabricating the patterns of optical device and fiber alignment and array using imprint process, and achieved higher precision of decreasing the dimensional error of the patterns by optimization of process. The fabricated optical interconnection of PLC device was measured 3.9 dB and 4.2 dB, lower than criteria specified by international standard.