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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 25, Issue 12 - Dec 2008
Volume 25, Issue 11 - Nov 2008
Volume 25, Issue 10 - Oct 2008
Volume 25, Issue 9 - Sep 2008
Volume 25, Issue 8 - Aug 2008
Volume 25, Issue 7 - Jul 2008
Volume 25, Issue 6 - Jun 2008
Volume 25, Issue 5 - May 2008
Volume 25, Issue 4 - Apr 2008
Volume 25, Issue 3 - Mar 2008
Volume 25, Issue 2 - Feb 2008
Volume 25, Issue 1 - Jan 2008
Selecting the target year
The Experimental Validation for the Optimization of Heating Tool Head for Minimized Temperature Distribution on Bonding Surface
Kweon, Sung-Hwan ; Kwon, Seol-Ryung ; Ko, Dong-Jin ; Park, Keum-Saeng ; Yang, Seung-Han ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 7~12
Optimization of Factors according to Process-variables in Pulse-type Cryogenic
Lee, Seong-Hoon ; Lee, Ju-Hong ; Kim, Pil-Kee ; Seok, Jong-Hyuk ; Oh, Byung-Joon ; Seok, Jong-Won ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 13~19
A Clean Level Test for a Precise Devise in CCM Assembly Process
Lee, Moon-Seok ; Park, Young-Jin ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 20~25
Fluid flow and Heat Transfer Analysis in the Motorized Stages for Manufacturing Automation of the Compact Camera Module
Kim, Tae-Young ; Kim, Sung-Jin ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 26~32
Command Transmitting/Receiving Method for Interlock Operation of Z-Axis VCM Drive System in Precision Assembler
Cho, Kyung-Rae ; Seok, Jul-Ki ; Gwak, Gi-Woong ; Kim, Gi-Woong ; Kim, Sang-Beom ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 33~39
Control of Tool Wear in Diamond Cutting of Steels by Intermittent Cutting Method
Chan, Song-Young ; Kentaro, Nezu ; Park, Chun-Hong ; Toshimichi, Moriwaki ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 40~46
Ultraprecision cutting of steels with geometrically defined single crystal diamond tools is handicapped by excessive tool wear. This paper presents a new approach to suppress the wear of single crystal diamond tool in cutting of steels. In general, it is said that the wear of diamond tool is caused by chemically reactive wear under high temperature and high pressure conditions. In order to suppress such chemical reactions, the time of contact between the diamond tool and the steel work in cutting was controlled by employing the intermittent cutting method such as fly-cutting. Series of intermittent cutting experiments have been carried out to control the tool-work contact time by changing one cycle of cutting length and cutting speed. The experimental results were shown that the tool wear was much dependent on the contact time regardless of the cutting speed, and that the wear was much suppressed by reducing the tool-work contact time. It is expected that the steels can be successfully cut with a single crystal diamond tool by controlling the contact time.
Analysis of the Warm Shrink Fitting Process for Assembling the Part(Shaft and Output Gear)
Kim, Tae-Jin ; Kang, Hee-Jun ; Kim, Chul ; Chu, Suck-Jae ; Kim, Ho-Yun ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 47~54
Fitting process carried out in the automobile transmission assembly line is classified into three classes; heat fitting, press fitting, and their combined fitting. Heat fitting is a method that heats gear to a suitable range under the tempering temperature and squeezes it toward the outer diameter of shaft. Its stress depends on the yield strength of gear. Press fitting is a method that generally squeezes gear toward that of shaft at room temperature by a press. Another method heats warmly gear and safely squeezes it toward that of shaft. Warm shrink fitting process for the automobile transmission part is now gradually increased, but the parts (shaft/gear) assembled by this process produced dimensional changes in both the outer diameter and profile of the gear. So that it may cause noise and vibration between gears. In order to solve these problems, we need an analysis of warm shrink fitting process, in which design parameters are involved; contact pressure according to fitting interference between outer diameter of shaft and inner diameter of gear, fitting temperature, and profile tolerance of gear. In this study, an closed form equation to predict contact pressure and fitting load was proposed in order to develop an optimization technique of the warm shrink fitting process and verified its reliability through the experimental results measured in the field and FEM, that is, thermal-structural coupled field analysis. Actual loads measured in the field was in good agreements with the results obtained by the theoretical and finite element analysis.
Error in Incremental Encoder Due to Vibration and Its Solution
Nam, Yoon-Su ; Park, Hae-Kyoon ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 55~61
Incremental encoder is a common choice for measuring the rotational angle of an axis. It produces, however, some measurement errors, if some kinds of rotational vibration are occurred. Even by increasing the number of slits on the circular peripheral, these kinds of error can not be removed. It only decreases the probability of the error being generated by making the magnitude of encoder resolution smaller than that of the axial vibration. This paper investigates the error mechanism of incremental encoder and suggests a digital logic circuit that prevents the measurement error to happen.
Design of an Adaptive Fuzzy Backstepping Controller for a Single-Link Flexible-Joint Robot
Kim, Young-Tae ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 62~70
An adaptive fuzzy backstepping controller is proposed for the motion control for a single-link flexible-joint robot in the presence of parametric uncertainties. Fuzzy logic system is used to approximate the uncertainties of functions and a backstepping technique is employed to deal with the mismatched problem. A compensation controller is also employed to estimates the bound of approximation error so that the shattering effect of the control effort can be reduced. Thus the asymptotic stability of the closed loop control system can be obtained based on a Lyapunov synthesis approach. Numerical simulation results for a single-link flexible-joint robot are included to show the effectiveness of proposed controller.
Electrostatic Suspension System of Glass Panels using Relay Feedback Control
Jeon, Jong-Up ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 71~79
In the manufacture of flat panel display devices, there is a strong demand for contactless glass panel handling devices that can manipulate a glass panel without contaminating or damaging it. To fulfill this requirement, an electrostatic suspension device far glass panels where the glass panel is supported by electrostatic forces without any mechanical contact is proposed. To implement the system with low cost and compactness, switched-voltage control scheme that is based on the relay feedback control is utilized. Relay feedback control method deploys only a single high-voltage power supply that can deliver a DC voltage of positive and/or negative polarity and thus high voltage amplifiers that are costly and bulky are not needed any more. It is shown that despite the inherent limit cycle property of the relay feedback based control, an excellent performance in vibration suppression is attained due to the presence of a relatively large squeeze film damping originating from the electrodes and levitated object. Using this scheme, a
glass panel was levitated stably with airgap variation decreasing down to
at an airgap of
Design of Electrostatic Suspension System
Jeon, Jong-Up ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 80~91
Electrostatic forces have an advantage of directly levitating not only non-ferromagnetic metals but also semiconductors, such as silicon wafers, and dielectric materials like glass. This paper describes the characteristics of electrostatic forces and electrostatic suspension system, followed by the basic principle of 1-DOF(degree of freedom) electrostatic suspension system, and the structures of electrodes-for-suspension and voltage supplying methods to the electrodes in 1-DOF model. This paper also discuss about the minimum number of electrodes needed to control n-DOF motion of the suspended object and represents some desirable electrode patterns to stabilize the 6-DOF motion of the object. In the near future, electrostatic suspension system is expected to be applied to industrial manufacturing processes, for example, to the manufacture of semiconductor devices and/or flat panel display devices.
A Study on the Piezoelectric Energy Harvesting Using SSHI Technique
Nam, Yoon-Su ; Park, Jong-Soo ; Park, Hae-Gyoon ; Lee, Jae-Kang ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 92~98
The target of this paper is to study on the usefulness of the SSHI technique as a wireless electrical power supply when it is driven by mechanical vibrations of low frequency. A THUNDER series a piezoelectric material (TH7-R), which has been developed by a NASA engineer is selected for this study. A mechanical motion vibrator supplies piezoelectric material with mechanical energy. An optical fiber sensor and a pulse generating circuit are used to accomplish the parallel-SSHI technique. As a result of this study, energy harvesting using SSHI technique results in a significant increase of the electrical power flow.
Effects of Crack and Tip Mass on Stability of Timoshenko Beam Subjected to Follower Force
Son, In-Soo ; Yoon, Han-Ik ; Ahn, Tae-Soo ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 99~107
In this paper, the stability of a cracked cantilever Timoshenko beam with a tip mass subjected to follower force is investigated. In addition, an analysis of the flutter instability(flutter critical follower force) and a critical natural frequency of a cracked cantilever Euler / Timoshenko beam with a tip mass subjected to a follower force is presented. The vibration analysis on such cracked beam is conducted to identify the critical follower force for flutter instability based on the variation of the first two resonant frequencies of the beam. Therefore, the effect of the crack's intensity, location and a tip mass on the flutter follower force is studied. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments. The crack is assumed to be in the first mode of fracture and to be always opened during the vibrations.
A Study of wear and Matching of Diesel Engine Exhaust Valve and Seat Insert Depending on Valve Materials
Kim, Yang-Soo ; Chun, Keyoung-Jin ; Hong, Jae-Soo ; Chung, Dong-Teak ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 108~115
The wear on engine valve and seat insert is one of the most important factors affecting engine performance. The engine valve and seat insert must be able to withstand the severe environment that is created by: high temperature exhaust gases generated while the engine is running, rapid movement of the valve spring, high pressure generated in the explosive process. In order to study such problems, a simulator has been developed to generate and control high temperatures and various speeds during motion. The wear simulator is considered to be a valid simulation of the engine valve and seat insert wear process with various speeds during engine activity. This work focused on the test of various degrees of wear on four different exhaust valve materials such as HRV40, HRV40-FNV (face nitrided valve), STL #32, STL #6,. Throughout all tests performed in this study, the outer surface temperature of the seat insert was controlled at
, the cycle number was
, the test load was 6860 N, the fuel was LPG the test speed was 20 Hz (2400 RPM) and the seat insert material was HVS1-2. The mean (standard deviation) maximum roughness of the exhaust valve and seat insert was
at the HRV40,
at the HRV40-FNV,
at the STL #32,
at the STL #6, respectively. It was discovered that the maximum roughness of exhaust valve was lower as the high temperature hardness of the valve material was higher under the same test conditions such as temperature, test speed, cycle number, test load and seat insert material. The set of the HRV40-FNV exhaust valve and the HVS1-2 seat insert showed the best wear resistance.
Estimation on a Contact Size Effect in Fretting Fatigue Between Cylindrical Pad and Flat Specimen
Kim, Jin-Kwang ; Cho, Sang-Bong ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 116~125
In general, fretting is a contact damage process due to micro-slip associated with small amplitude oscillatory movement between two surfaces in contact. Previous studies in fretting fatigue have observed a contact size effect related to contact width. The volume-averaging method of theoretically predicted contact stress fields was required to emulate experimental trends and to predict the observed contact size effects. This contact size effect is captured by the mean values of stresses and strains at the element integration points of FE model and two critical plane models (SWT, FS) in the present paper. It is shown that crack nucleation and fretting fatigue life can be predicted by the FE-based critical plane models.
A Study on Improvement of the Thermal Stability for Development of Linear Motors with High Speed and Accuracy
Hwang, Young-Kug ; Lee, Choon-Man ; Eun, In-Ung ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 126~133
Linear motors are efficient mechanism that offers high speed and positioning accuracy. By eliminating mechanical transmission mechanisms such as ball screw or rack-pinion, much higher speed and greater acceleration can be achieved without backlash or excessive friction. However, an important disadvantage of linear motor system is its high power loss and heating up of motor and neighboring machine components on operation. For the application of the linear motors to precision machine tools an effective cooling method and thermal optimizing measures are required. This paper presents an investigation into the thermal behavior of linear motors with the objective of deriving the optimum cooling conditions. To reach these goals several experiments were carried out, varying operating and cooling conditions. From the experimental results, this research proposed cooling conditions to improve the thermal characteristics of the linear motors.
Study on the Air Bearings with Actively Controllable Magnetic Preloads for an Ultra-precision Linear Stage
Ro, Seung-Kook ; Kim, Soo-Hyun ; Kwak, Yoon-Keun ; Park, Chun-Hong ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 134~142
In this paper, we propose a precise linear motion stage supported by magnetically preloaded air bearings. The eight aerostatic bearings with rectangular carbon porous pads were located only one side of vertical direction under the platen where four bearings are in both sides of horizontal direction as wrap-around-design, and this gives simpler configuration than which constrained by air bearings for all direction. Each of the magnetic actuators has a permanent magnet generating static magnetic flux far required preload and a coil to perturb the magnetic farce resulting adjustment of air- bearing clearance. The characteristics of porous aerostatic bearing are analyzed by numerical analysis, and analytic magnetic circuit model is driven for magnetic actuator to calculate preload and variation of force due to current. A 1-axis linear stage motorized with a coreless linear motor and a linear encoder was designed and built to verify this design concept. The load capacity, stiffness and preload force were examined and compared with analysis. With the active magnetic preloading actuators controlled with DSP board and PWM power amplifiers, the active on-line adjusting tests about the vertical, pitching and rolling motion were performed. It was shown that motion control far three DOF motions were linear and independent after calibration of the control gains.
A Study on the Novel Micro Mixer for the Application of LOC
Choi, Bum-Kyoo ; Lee, Seung-Hyeon ; Kang, Ho-Jin ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 143~149
This paper presents the results of the study on the novel micro mixer. Existing micro mixer is classified as active mixing and passive mixing by the mixing principles. Both mixing principles have problems. For solving these problems, this research has developed the novel micro mixers based on a totally different principle compared with former mixers. They not only have a simpler structure than former ones but also are able to achieve high mixing efficiency in spite of low power consumption due to using Lorentz Force. In addition, they are designed to increase the efficiency of mixing by changing the rotating direction of fluid with a polar switching circuit. Driving forces of the mixer are Lorentz force and a moving force of fluid due to electrophoresis. Because the efficiency of mixer is affected by electrode shape, several models have been made. The computer simulation has been made to estimate the efficiency of each mixer.
Research for Patent Application Tendency in the In-Line System Manufacturing for Component of Nano Scale
Kim, Seung-Min ; Ko, Jun-Bin ; Park, Hee-Sang ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 150~158
This research considered that the significance of the NT(Nano Technology) which gradually increased the importance of it and investigated the technology development current situation of the Korea, U.S.A, Japanese, Europe. Therefore, in domestic and foreign, this research was widely used. It includes the tendency of the technology about processing methods using the ion beam and electron beam among the In-line system related technique field for the high efficiency energy beam application nano scale manufacturing components. The technique level of Korea, the international trend of technology and cooperation research present condition are dealt in. The information about the checked out of business of research and development of the country consistency and policy establishment try to be provided.
Experimental Study of Cutting force and Surface Roughness Prediction in MQL Tooling of Al 6061
Hwang, Young-Kug ; Chung, Won-Jee ; Lee, Choon-Man ;
Journal of the Korean Society for Precision Engineering, volume 25, issue 6, 2008, Pages 159~167
Cooling lubricants are used in machining operations in order to reduce friction at the tool-chip and tool-workpiece interfaces, cool both chip and tool, and remove chip. Furthermore, they influence a strong effect on the shearing mechanisms and, consequently, on the machined surface quality and tool wear. However, several researchers state that the costs related to cutting fluids is frequently higher than those related to cutting tools. Moreover, the cooling lubricants cause an increase in both worker's health and social problems related to their use and correct disposal. Therefore, many researchers have focused on the environmentally conscious machining technologies. One of the technologies is known as MQL(Minimum Quantity Lubrication) machining. In this paper, an experimental model to obtain the optimal cutting conditions in MQL turning was suggested, and the effects of cutting conditions on surface roughness and cutting force were analyzed. For these purposes, FFD (Fractional Factorial Design) and RSM (Response Surface Methods) were used for the experiment. Cutting force and surface roughness with different cutting conditions were measured through the external cylindrical turning of Al 6061 based on the experiment plan. The measured data were analyzed by regression analysis and verification experiments with random conditions were conducted to confirm the suggested experimental model.