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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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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 21, Issue 12 - Dec 2004
Volume 21, Issue 11 - Nov 2004
Volume 21, Issue 10 - Oct 2004
Volume 21, Issue 9 - Sep 2004
Volume 21, Issue 8 - Aug 2004
Volume 21, Issue 7 - Jul 2004
Volume 21, Issue 6 - Jun 2004
Volume 21, Issue 5 - May 2004
Volume 21, Issue 4 - Apr 2004
Volume 21, Issue 3 - Mar 2004
Volume 21, Issue 2 - Feb 2004
Volume 21, Issue 1 - Jan 2004
Selecting the target year
Intelligent Home-Care System
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 7~13
Customized Environment Design and Control for the Elderly
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 14~20
A Study on Die of Bearing Rubber Seal by Formed Tool
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 21~26
The formed tool is used to machine the geometrical shape of bearing rubber seal efficiently. The bearing rubber seal has complex geometry for the complicated geometrical shape to prevent leakage of lubricant oil and influx of the dust effectively. Because it is difficult to machine the unique shape exactly by the conventional tool, the formed tool is used in machining a rubber seal die. In this paper, It is performed to investigate machining characteristic of the formed tool； cutting edge wear, cutting force, and surface quality. Also, an efficient precision machining condition is proposed, and the inspection results of rubber seal with CAI are discussed.
A study on searching method of molding condition to control the thickness reduction of optical lens in plastic injection molding process
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 27~34
In the injection molding of plastic optical lenses, the molding conditions have critical effects on the quality of the molded lenses. Since there are many molding parameters involved in injection molding process, determination of the molding conditions for lens molding is very important in order to precisely control the surface contours of an optical lens. Therefore this paper presents the application of neural network in suggesting the optimized molding conditions for improving the quality of molded parts based on data of FE Analysis carried out through CAE software, Timon-3D. Suggested model in this paper, which serves to learn from the data of FE Analysis and induce the values for optimized molding conditions. has been implemented for searching the molding conditions without void and with minimized thickness shrinkage at lens center of injection molding optical lens. As the result of this study. we have confirmed that void creation at the inside of lens is primarily determined by mold temperature and thickness shrinkage at center of lens is primarily determined by the parameters such as holding pressure and mold temperature.
Position Control of Sliding Mode Control Systems with Compensation of Estimated Coulomb friction
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 35~42
The control systems with friction cause the steady state error and slow response, because friction is a sensitive to the change of system condition and has highly nonlinear characteristics. To overcome these problems and do precise position control for a ball-screw system, we use Coulomb friction estimator and the sliding mode control(SMC) to compensate its negative effect. The applied SMC for tracking position has a characteristics of robust stability and reducing chattering, and is derived from the Lyapunov stability theorem and reaching condition. Compensating the estimated friction torque to the bounded disturbance term of the SMC's equivalent control input, it has a tracking performance better than the PID from the experimental results.
Powerflow Simulation Software of the Automotive Powertrain through the Combination of the Components (I)： Development of the Automatic Powerflow Generation Module
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 43~51
In this paper, the element combination algorithm for designing an arbitrary type of the automatic transmissions is proposed. The powertrain simulation software using this algorithm is then developed. The deliveries of the angular velocities and torques are only considered for the motion characteristics of the automatic transmissions. The effects of the vibration and noise are not considered. The automatic transmission is defined by the basic elements, i.e., planetary gear set, clutch, brake, shaft, general gear, and inertia. The transmission system is defined by the combination of these elements. The element combination matrices automatically generate the equations of motion for each shift. The self error-correcting algorithm is also developed to verify the element combination algorithm. This automotive powertrain simulation/design software with user-friendly graphic user interface has two main modules. The first module, the automatic powerflow generation module, mainly consists of the automatic powerflow and component generation algorithms. This paper covers the theory and application for the first module. The second module deals with the automatic system generation algorithm and will be discussed in the second paper.
Powerflow Simulation Software of the Automotive Powertrain through the Combination of the Components (II)： Development of the Automatic System Generation Module
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 52~59
In this paper, the automatic system generation algorithm based on the element combination algorithm discussed in the first part of this paper for designing an arbitrary type of the automatic transmissions is proposed. The powertrain design software using these algorithms is developed. This automotive powertrain design software with user-friendly graphic user interface has two main modules. The first module, the automatic power flow generation module, is already discussed in the previous paper. The second module dealing with the automatic system generation algorithm is discussed in this paper. The power-flow simulation software fur the arbitrary type of powertrain is then developed. The simulation and experimental results of the vehicle equipped with two planetary gear type automatic transmission are compared to validate the proposed algorithms and developed software. The simulation results demonstrate the good agreement with the experimental results.
A Study on the Flame Monitoring System Development
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 60~66
Increased energy costs have placed demands for improved combustion efficiency, high equipment availability, low maintenance and safe operation. Simultaneously low NOx modification, installed due to stricter environmental legislations, require very careful combustion management. The flame diagnostics system has been developed specially to meet these requirements. We aimed at gaining the relationship between burner flame image and emissions such as NOx and unburned carbon in furnace by utilizing the image processing method. For the first step of development, its possibility test was undertaken with bench furnace. The test proceeded to the second step with pilot furnace, the system was observed to be effective for evaluating the combustion conditions.
Dynamic Modeling and LQG/LTR Controller Design for the Flexible Structures
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 67~73
Some of Spacecraft's structures are flexible so that a certain expected disturbance can easily excite a low frequency vibration on these structures, having very low natural damping. Such vibration will degrade the performance of the system, which should to be kept in a specific shape or attitude against the undesired vibration. In this paper, LQG/LTR controller is developed using an additional dynamic model to increase the performance of the frequency responses at low frequency area. This study presents that the LQG/LTR design was an effective controller for the flexible structure.
Disturbance Compensation Control of An Active Magnetic Bearing System by Multiple FXLMS Algorithm - Theory
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 74~82
In this paper, a disturbance feedforward compensator design technique is proposed for an active magnetic bearing system subject to base motion for attenuating disturbance responses. In the consideration of the requirements on the model accuracy in the model based compensator designs, an experimental feedforward compensator design based on adaptive estimation by means of the Multiple Filtered-x least mean square(MFXLMS) algorithm is proposed. The performance and the effectiveness of the proposed technique will be presented in the succeeding paper in which the proposed technique is applied to a 2-DOF active magnetic bearing system subject to base motion.
Disturbance Compensation Control of An Active Magnetic Bearing System by Multiple FXLMS Algorithm - Experiments
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 83~91
This paper illustrates the feasibility and the effectiveness of the disturbance feedforward compensation control proposed in the previous paper. The compensator is designed experimentally by means of the Multiple Filtered-x Least Mean Square algorithm. A 2-DOF active magnetic bearing system subject to base motion is built and the compensation control is applied. The experimental results demonstrate that the compensation control reduces the air-gap responses within 10
of those by the feedback control alone without increasing the control inputs.
Error Analysis and Alignment Tolerancing for Confocal Scanning Microscope using Monte Carlo Method
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 92~99
The errors can cause the serious loss of the performance of a precision machine system. In this paper, we proposed the method of allocating the alignment tolerances of the parts and applied this method to get the optimal tolerances of a Confocal Scanning Microscope. In general, tight tolerances are required to maintain the performance of a system, but a high cost of manufacturing and assembling is required to preserve the tight tolerances. The purpose of allocating the optimal tolerances is minimizing the cost while keeping the high performance of the system. In the optimal problem, we maximized the tolerances while maintaining the performance requirements. The Monte Carlo Method, a statistical simulation method, is used in tolerance analysis. Alignment tolerances of optical components of the confocal scanning microscope are optimized to minimize the cost and to maintain the observation performance of the microscope. We can also apply this method to the other precision machine system.
Development of a Web-based Powertrain Performance Simulation System
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 100~107
The development of a Web-based powertrain performance simulation system is introduced. The development approach of system architecture and each module is introduced along with the H/W and S/W used. The interface with all users is developed via a JAVA Applet. The powertrain modeling and other job history data of a user is managed systematically on the server by database to increase the reusability of the data. A self-developed program using object-oriented programming is used as a solver for the performance simulation. The graph tool for the analysis of simulation results has the collaboration support developed based on JAVA so that synchronous users can view the same result. As a result, the powertrain simulation is possible only with Web-browser for the user and the collaboration support among the relevant engineers is possible.
Numerical Simulation and Experimental Studies on Lubricating System of Scroll Compressor
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 108~115
Experiment and analytical studies on the oil supply characteristics of scroll compressor have been presented. For a scroll compressor, oil supply system consisting of individual lubricating element such as pumps, oil passages and sliding surfaces has been modeled by equivalent electric circuit. By solving the closed network equations of the model, oil flow rates at various lubrication elements could be obtained. Total amount of the oil flow rate drawn into the shaft has been measured and compared reasonably well with the prediction by the numerical simulation.
Development of Static-explicit rigid-plastic finite Element Method and Investigate the offset of strain increment in Osakada method
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 116~121
In rigid-plastic finite element method, there is a heavy computation time and convergence problem. In this study, static-explicit rigid-plastic finite element method will be introduced. This method is the way that restrict the convergence interval. It is expected that various results from the numerical analysis will give very useful information for the design of tools in sheet metal forming process.
Prediction of thermal shock failure of glass during PDP manufacturing process
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 122~129
There is an increasing need for large flat panel display devices. PDP (Plasma Display Panel) is one of the most promising candidates for this need. Thermal shock failure of PDP glass during manufacturing process is a critical issue in PDP industry since it is closely related to the product yield and the production speed. In this study, thermal shock resistance of PDP glass is measured by water quenching test and an analysis scheme is described for estimating transient temperature and stress distributions during thermal shock. Based on the experimental data and the analysis results, a simple procedure for predicting the thermal shock failure of PDP glass is proposed. The fast cooling process for heated glass plates can accelerate the speed of PDP production, but often leads to thermal shock failure of the glass plates. Therefore, a design guideline for preventing the failure is presented from a viewpoint of high speed PDP manufacturing process. This design guideline can be used for PDP process design and thermal -shock failure prevention.
A Study on Development of Railway Reducer for Low Noise/Vibration
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 130~137
A dynamic model of railway reducer is developed by the lumped parameter method. The model accounts for shafts, bearings flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Vibration/noise analysis as well as strength of gear teeth, and bearing life are considered. Excitation forces of railway reduction are considered as the mass unbalance of the rotors, misalignment and a function of gear transmission error which comes from the modified tooth surface. A campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors, misalignment and the transmitted errors of the gearing are considered, shows that, at the operating speed, there are not the critical speed. The program which can be used to analyze and predict vibration/noise characteristics by mass unbalance, misalignment and gear transmission error of railway reduction is developed with this system model.
A Study on the Creep Characteristics of Solder of 63 Sn-37Pb
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 138~144
The initiation and the propagation of solder joint crack depend on its environmental conditions, such as high temperature creep and thermal fatigue. Creep is known to be the most important factor for the mechanical failure of solder joints in micro-electronic components and micro-systems. This is mainly caused by the different thermal expansion coefficients of the materials used in the micro-electronic packages. To determine the reliability of solder joints and consequently the electronic components, the characterization of the creep behavior of this group of materials is crucial. This paper is to apply the theory of creep into solder joints and to provide related technical information needed for evaluation of reliability of solder joint to failure. 63Sn-37Pb solder was used in this study. This paper experimentally shows a way to enhance the reliability of solder joints.
Configuration Design using a Genetic Algorithm in the Embodiment Design Phase
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 145~152
This paper proposes a representation for the embodiment design of mechanical structures and a genetic algorithm suited for the representation. In order to represent early stages and latter stages of the embodiment design, the designs are modeled as simultaneous multi-objective optimization problems of parametric designs for parts and of layout generation for structures. The study, thus, involves genotypes that are adequate to represent phenotypes of the models for the genetic algorithm to solve the given problems. We demonstrate the implementation of the genetic algorithm with the result applied to the gear equipment design.
A Study on the Minimum Weight Design for Flexible Structure
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 153~159
A control-structure combined optimal design problem is discussed taking a 3-D truss structure as a design object. We use descriptor forms for a controlled object and a generalized plant because the structural parameters appear naturally in these forms. We consider not only minimum weight design problem for structure system, but also suppression problem of the effect of disturbances for control system as the purpose of the design. By minimizing the linear sum of the normalized structural objective function and control objective function, it is possible to make optimal design by which the balance of the structural weight and the control performance is taken.
Robust Optimization Design of Overhead Crane with Constraint using the Characteristic Functions
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 160~167
The correlation between the object function and the design parameter is shown on this paper by using the characteristic function for the mixed result of the structural analysis, the buckling analysis and the table of orthogonal array according to the original overhead crane's dimensional change. About the above two functions, the effectiveness of design change according to the change of design parameters could be estimated. Also, the overhead crane's weight is reduced up to 10.55 percent maintaining the structural stability according to the thickness of plate.
Effect of Hardness and Substructure on Long-term Creep Behavior of Mod.9Cr-1Mo Steel
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 168~176
Interrupted creep tests were carried out on the Mod.9Cr-1Mo steel in order to investigate the structural degradation during creep. The ranges of creep stress and temperature were from 71 to 167MPa and 873 to 923k, respectively. The change of hardness and tempered martensitic lath width were measured in the grip and gauge parts of interrupted specimens. The lath structure was thermally stable in static conditions, but was not stable during creep, and the structural evolution was enhanced by creep strain. The relation between the change in lath width and strain was described in the from,
W= a (
is the strain,
is the initial lath width,
is the final lath width depending solely on stress, and a is the constant of the magnitude of 0.67
m /strain. The change in Victors hardness was expressed by a one-valued function of creep life consumption ratio. Based on the empirical relation between strain and lath width, a model was proposed to explain the relation between change in hardness and creep life consumption ratio. The model revealed that about 65
of dislocations in lath structures were eliminated by the migration of subboundaries.
The effect of coating wire on the performance of wire electrical discharge machining
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 177~185
The machining performance of wire electrical discharge machining(WEDM), such as cutting speed, surface roughness and straightness depend on the electrode, and the machining parameters are diverse and affect each other. Therefore operator must have a lot of experiences of the parameter for the better machining performance in WEDM. An approach to minimize the time for determining of parameters setting is proposed. Based on the Taguchi method, the significant factors affecting the machining performance are determined. Types of electrodes are arranged at inner array in tables of orthogonal arrays so that we can estimate machining performances of each electrode. Coating wire shows better performances than brass wire in cutting speed but it produces poor surface roughness, and two wires shows similar performance in straightness
Development of micro-stereolithography system for the fabrication of three-dimensional micro-structures
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 186~194
Micro-stereolithography is a newly proposed technology as a means that can fabricate a 3D micro-structure of free form. It makes a 3D micro-structure by dividing the shape into many slices of relevant thickness along horizontal surfaces, hardening each layer of slice with a focused laser beam, and stacking them up to a desired shape. In this technology, differently from the conventional stereolithography, scale effect is dominant. To realize micro-stereolithography technology, we developed the micro-stereolithography apparatus which is composed of an Ar+ laser, x-y-z stages. controllers. optical devices and scan path generation software. Related processes were developed, too. Using the system, a number of micro-structures were successfully fabricated. Some of these samples are shown for prove this system. Laser scan path generation algorithm and software considering photopolymer solidification phenomena as well as given 3D model were developed. Sample fabrication of developed software shows relatively high dimensional accuracy compared to the uncompensated result.
The Flow Analysis and Evaluation of the Peristaltic Micropump
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 195~202
This paper presents the fabrication and evaluation of mechanical behavior for a peristaltic micropump by flow simulation. The valve-less micropump using the diffuser/nozzle is consists of the lower plate, the middle plate, the upper plate and the tube that connects inlet and outlet of the pump. The lower plate includes the channel and the chamber, and the plain middle plate are made of glass and actuated by the piezoelectric translator. Channels and a chamber on the lower plate are fabricated on high processability silicon wafer by the DRIE(Deep Reactive Ion Etching) process. The upper plate does the roll of a pump cover and has inlet/outlet/electric holes. Three plates are laminated by the aligner and bonded by the anodic bonding process. Flow simulation is performed using error-reduced finite volume method (FVM). As results of the flow simulation and experiments, the single chamber pump has severe flow problems, such as a backflow and large fluctuation of a flow rate. It is proved that the double-chamber micropump proposed in this paper can reduce the drawback of the single-chamber one.
Modeling and Experimental Response Characterization of the Chevron-type Bi-stable Micromachined Actuator
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 203~209
Compliant bi-stable mechanism allows two stable states within its operation range staying at one of the local minimum states of the potential energy. Energy storage characteristics of the bi-stable mechanism offer two distinct and repeatable stable states, which require no power input to maintain it at each stable state. This paper suggests an equivalent model of the chevron-type bi-stable microactuator using the equivalent spring stiffness in the rectilinear and the rotational directions. From this model the range of spring stiffness where the bi-stable mechanism can be operated is analyzed and compared with the results of the FEA (Finite Element Analysis) using ANSYS for the buckling analysis, both of which show a good agreement. Based on the analysis, a newly designed chevron-type bi-stable MEMS actuator using hinges is suggested for the latch-up operation. It is found that the experimental response characteristics of around 36V for the bi-stable actuation for the 60
stroke correspond very well to the results of the equivalent model analysis after the change in cross-sectional area by the fabrication process is taken into account. Together with the resonance frequency experiment where 1760Hz is measured, it is shown that the chevron-type bi-stable MEMS actuator using hinges is applicable to the optical switch as an actuator.
Development of a Nano Replication Printing(nRP) Process using a Voxel Matrix Scanning Scheme
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 210~217
In this study, a new process, named as nano replication printing(nRP) process, is developed for printing any figure in the range of several micrometers by using voxel matrix scanning scheme. In this newly developed process, a femto-second laser is scanned on a photosensitive monomer resin in order to induce polymerization of the liquid resin according to a voxel matrix which is transformed from bitmap format file. After the polymerization, a droplet of ethanol is dropt to remove the unnecessary remaining liquid resin and then the polymerized figures with nano-scaled precision are only remaining on the glass plate. By the nRP process, any figure file of bitmap format could be reproduced as nano-scaled precision replication in the range of several micrometers. Also, nano/micro-scaled patterns for an extremely wide range of applications would become a technologically feasible reality. Some of figures with nano-scaled precision were printed in scaled replication as examples to prove the usefulness of this study.
A Study on the Micro-lapping process of Sapphire Wafers for optoelectronic devices
Journal of the Korean Society for Precision Engineering, volume 21, issue 2, 2004, Pages 218~223
The sapphire wafers for blue light emitting devices were manufactured by the implementation of the surface machining technology based on micro-tribology. This process has been performed by Micro-lapping process. The sapphire crystalline wafers were characterized by double crystal X-ray diffraction. The sample quality of crystalline sapphire wafer at surface has a full width at half maximum of 250 arcsec. This value at the surface sapphire wafer surfaces indicated 0.12
sizes. Surfaces of sapphire wafers were mechanically affected by residual stress and surface default. As a result, the value of surface roughness of sapphire wafers measured by AFM(Atom Force Microscope) was 2.1nm.