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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 22, Issue 12 - Dec 2005
Volume 22, Issue 11 - Nov 2005
Volume 22, Issue 10 - Oct 2005
Volume 22, Issue 9 - Sep 2005
Volume 22, Issue 8 - Aug 2005
Volume 22, Issue 7 - Jul 2005
Volume 22, Issue 6 - Jun 2005
Volume 22, Issue 5 - May 2005
Volume 22, Issue 4 - Apr 2005
Volume 22, Issue 3 - Mar 2005
Volume 22, Issue 2 - Feb 2005
Volume 22, Issue 1 - Jan 2005
Selecting the target year
Development Trends of Ceramic Composite Armors for Combat Vehicles
Ahn Sung-Hoon ; Jung Woo-Kyun ; Kim Hee-Jae ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 7~18
Influence of process parameters on the kerfwidth for the case of laser cutting of CPS 1N sheet using high power CW Nd:YAG laser
Kim Min-Su ; Lee Sang-Hoon ; Park Hyung-Jun ; Yoo Young-Tae ; Ahn Dong-Gyu ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 19~26
The objective of this study is to investigate the influence of process parameters, such as power of laser, cutting speed of laser and material thickness, on the practical cutting region and the kerfwidth fer the case of cutting of CSP IN sheet using high power Nd:YAC laser in continuous wave(CW) mode. In order to obtain the practical cutting region and the relationship between process parameters on the kerfwidth, several laser cutting experiments are carried out. The effective heat input is introduced to consider the influence of power and cutting speed of laser on the kerfwidth together. From the results of experiments, the allowable cutting region and the relationship between the effective heat input and kerfwidth fur the case of cutting of CSP 1N sheet using high power CW Nd:YAG laser have been obtained to improve the dimensionalaccuracyofthecutarea.
Development of Statistical Model for Line Width Estimation in Laser Micro Material Processing Using Optical Sensor
Park Young Whan ; Rhee Sehun ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 27~37
Direct writing technology on the silicon wafer surface is used to reduce the size of the chip as the miniature trend in electronic circuit. In order to improve the productivity and efficiency, the real time quality estimation is very important in each semiconductor process. In laser marking, marking quality is determined by readability which is dependant on the contrast of surface, the line width, and the melting depth. Many researchers have tried to find theoretical and numerical estimation models fur groove geometry. However, these models are limited to be applied to the real system. In this study, the estimation system for the line width during the laser marking was proposed by process monitoring method. The light intensity emitted by plasma which is produced when irradiating the laser to the silicon wafer was measured using the optical sensor. Because the laser marking is too fast to measure with external sensor, we build up the coaxial monitoring system. Analysis for the correlation between the acquired signals and the line width according to the change of laser power was carried out. Also, we developed the models enabling the estimation of line width of the laser marking through the statistical regression models and may see that their estimating performances were excellent.
Effects of Beam Parameters on Excimer Laser Ablation
Bang Se Yoon ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 38~46
In laser machining such as drilling with
or Nd:YAG laser, and etching or ablation with Excimer laser, one of the most important parameters affecting the machining is known to be beam characteristics. In this paper a numerical study is performed to investigate the effects of beam parameters, especially in the process of excimer laser ablation of polymers. Results of different beam conditions reveal that if the ablated depth is small compared to beam size the simple photochemical etching model is suitable to predict the etched shape, and that the importance of precise alignment becomes large as beam quality factor becomes larger.
Micro EDM with Ultrasonic Work Fluid Vibration for Deep Hole Machining
Je Sung Uk ; Lee Hae Sung ; Chu Chong Nam ; Kim Duck Whan ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 47~53
Microholes with high aspect ratio are required in microstructures. Among various methods for producing the microhole, micro electrical discharge machining (MEDM) is very effective and useful process. But, it is difficult to machine the high aspect ratio holes below
in diameter because machining condition becomes unstable due to bad removal of debris at deep hole. In this paper, ultrasonic vibration is applied to MEDM work fluid to make a high aspect ratio micro hole. It is shown that the vibration is effective in circulating the debris and increasing the machining rate. As a result, produced was a micro hole with
exit diameter and aspect ratio 23.
Development of a Simulation Program for Virtual Laser Machining
Lee Ho Yong ; Lim Joong Yeon ; Shin Kui Sung ; Yoon Kyung Koo ; Whang Kyung Hyun ; Bang Se Yoon ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 54~61
A simulator for virtual laser machining is developed to help understanding and predicting the effects of machining parameters on the final machined results. Main program is based on the model for polymer ablation with short pulse excimer lasers. Version f of the simulator is built using Visual Fortran to make the user work under visual environment such as Windows on PC, where the important machining parameters can be input via dialog box and the calculated results for machined shape, beam fluence, and temperature distribution can be plotted through the 2-D graphics windows. Version II of the simulator is built using HTML, CGI and JAVA languages, allowing the user to control the input parameters and to see the results plot through the internet.
A Study on the Time-Dependent Deformation Behaviors of PMMA in Nanoindentation Process for Hyperfine Pit Structure Fabrication
Kim Hyun-Il ; Kang Chung-Gil ; Youn Sung-Won ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 62~70
The nanoindenter and AFM have been used for nanofabrication, such as nanolithography, nanowriting, and nanopatterning, as well as measurement of mechanical properties and surface topology. Nanoscale indents can be used as cells for molecular electronics and drug delivery, slots for integration into nanodevices, and defects for tailoring the structure and properties. Therefore, it is very important to make indents of desired morphology (shape, size and depth). Indents of different shapes can be obtained by using indenters of different geometries such as a cube comer and conical and spherical tips. The depth and size of indents can be controlled by making indentations at different indentation loads. However, in case of viscoplastic viscoelastic materials such as polymethylmethacrylate (PMMA) the time dependent deformation (TDD) should also be considered. In this study, the effect of process parameters such as loading rate and hold-time at peak load on the indent morphology (maximum penetration depth, elastic recovery, transient creep recovery, residual depth pile-up height) of PMMA were studied for hyperfine pattern fabrication.
A Study of Mechanochemical Hyperfine-Writing Technique Using Deformation Induced Etch Hillock Phenomena
Kang Chung Gil ; Youn Sung Won ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 71~78
The purpose of this study is to suggest a hyperfine maskless writing technique by using the nanoindentation and HF wet etching technique. Indents were made on the surface of Pyrex7740 glass by the hyperfine indentation process with a Berkovich diamond indenter, and they were etched in
HF solution. After etching process, convex structure was obtained due to the deformation-induced hillock phenomena. In this study, effects of indentation process parameters (etching time, normal load, loading .ate, hold-time at the maximum load) on the morphologies of the indented surfaces after isotopic etching were investigated from an angle of deformation energies. Finally, sample characters were written to show the possibility of the application.
Modeling of Laser Micromachining of Quasi-three-dimensional Shapes
Shin Kui Sung ; Yoon Kyung Koo ; Whang Kyung Hyun ; Bang Se Yoon ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 79~87
This paper summarizes the work on the development of a simulation program for modelling the process of machining quasi-three dimensional shape with the excimer laser beam on a constantly moving polymers. Relatively simple masks of rectangle, triangle and half circle shape are considered. The etching depth is calculated by considering the number of laser pulses irradiated on the specimen surface. It was found that similar shapes as experimental results can be obtained by choosing suitable parameters of moving velocity, moving distance and mask sizes.
A Study on 3-D Shape Measurement and Application by using Digital Projection
( I )
Ryu Weon-Jae ; Rho Hyung-Min ; Lee Dong-Hwan ; Kang Young-June ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 88~93
topography method is a well-known non-contacting 3-D measurement method. Recently, the automatic 3-D measurement by
topography has been required, since the method was frequently applied to the engineering and medical fields. The 3-D measurement using projection
topography is very attractive because of its high measuring speed and high sensitivity. In this paper, using two-wavelength method of projection
topography was tested to measuring object with
problems. The experimental results prove that the proposed scheme is capable of finding absolute fringe orders, so that the
problems can be effectively overcome so as to treat large step discontinuities in measured objects.
Precision Position Control of Piezoelectric Actuator Using Feedforward Hysteresis Compensation and Neural Network
Kim HyoungSeog ; Lee Soo Hee ; Ahn KyungKwan ; Lee ByungRyong ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 94~101
This work proposes a new method for describing the hysteresis non-linearity of a piezoelectric actuator. The hysteresis behaviour of piezoelectric actuators, including the minor loop trajectory, are modeled by geometrical relationship between a reference major loop and its minor loops. This hysteresis model is transformed into inverse hysteresis model in order to output compensated voltage with regard to the given input displacement. A feedforward neural network, which is trained by a feedback PID control module, is incorporated to the inverse hysteresis model to compensate unknown dynamics of the piezoelectric system. To show the feasibility of the proposed feedforward-feedback controller, some experiments have been carried out and the tracking performance was compared to that of simple PTD controller.
A Position Control for a Parallel Stage with 6 degrees of freedom Using Magnetic Actuators
Lee Se-Han ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 102~111
In this paper, we address a position control for a parallel stage, which is levitated and driven by electric magnetic force. This consists of a levitating object (called platen) with 4 permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion by the vertical and horizontal force. A dynamic equation of the stage system is derived based on Newton-Euler method and it's special Jacobian matrix describing a relation between the limited velocity and Cartesian velocity is done. There are proposed two control methods for positioning which are Cartesian space controller and Actuator space controller. The control performance of the Cartesian space controller is better than the Actuator space controller in task space trajectory while the Actuator space controller is simpler than the Cartesian space controller in controller realization.
A Smooth Trajectory Generation for an Inverted Pendulum Type Biped Robot
Noh Kyung-Kon ; Kong Jung-Shik ; Kim Jin-Geol ; Kang Chan-Soo ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 112~121
This paper is concerned with smooth trajectory generation of biped robot which has inverted pendulum type balancing weight. Genetic algorithm is used to generate the trajectory of the leg and balancing weight. Balancing trajectory can be determined by solving the second order differential equation under the condition that the reference ZMP (Zero moment point) is settled. Reference ZMP effect on gait pattern absolutely but the problem is how to determine the reference ZMP. Genetic algorithm can find optimal solution under the high order nonlinear situation. Optimal trajectory is generated when use genetic algorithm which has some genes and a fitness function. In this paper, minimization of balancing joints motion is used for the fitness function and set the weight factor of the two balancing joints at the fitness function. Inverted pendulum type balancing weight is very similar with human and this model can be used fur humanoid robot. Simulation results show ZMP trajectory and the walking experiment made on the real biped robot IWR-IV.
Development of CAM system for 5-axis automatic roughing machine Based on Reverse Engineering
Kim Hwa Young ; Son Seong Min ; Ahn Jung Hwan ; Kang Dong Bae ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 122~129
Shoe with leather upper such as safety and golf shoe requires a roughing process where the upper is roughed fur helping outsole to be cemented well. It is an important and basic process for production of leather shoe but is not automated yet. Thus, there are problems that the defect rate is high and the quality of roughed surface is not uniform. In order to solve such problems, the interest in automation of roughing process is being increased and this paper introduces CAM system for 5-axis automatic roughing machine as one part of automation of roughing process. The CAM system developed interpolates a B-spline curve using points measured from the Roughing Path Measurement System. The B-spline curve is used to generate the tool path and orientation data fer a roughing tool which has not only stiffness but also flexibility to rough the inclined surface efficiently. For productivity, the upper of shoe is machined by side of the roughing tool and tool offset is applied to the roughing tool for machining of inclined surface. The generated NC code was applied to 5-axis polishing machine for the test. The upper of shoe was roughed well along the roughing path data from CAM and the roughed surface was proper fur cementing of the outsole.
A Study on the MR Cylinder with Built-in alves
Song Joo-Young ; Ahn Kyoung-Kwan ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 130~136
A new MR cylinder with built-in valves using MR fluid (MR valve) is suggested and fabricated fur fluid control systems. The MR fluid is a newly developed functional fluid whose obvious viscosity is controlled by the applied magnetic field intensity. The MR cylinder is composed of cylinder with small clearance and piston with electromagnet. The differential pressure is controlled by the applied magnetic field intensity. It has the characteristics of simple, compact and reliable structure. The size of MR cylinder and piston has
in face size, respectively and 0.8mm in gap length. Through experiments, it was found that the differential pressure is controlled by the applied magnetic field intensity under little influence of the flow rate, which corresponds to a pressure control valve. The differential pressure of 0.47MPa was obtained with the input current of 1.5A. The rising time was 2.3s in step response of a manipulator using the MR cylinder. The effectiveness of the MR cylinder was also demonstrated through the position control.
Contact Detection Algorithm of the Z-axis of a Wire Bonder
Kim Jung-Han ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 137~145
A new design of contact detection algorithm is proposed for the z-axis of a wire bonder that interconnects between pads and leads in semiconductor manufacturing processes. Fast and stable contact detection of the z-axis is extremely important fer maintaining proper quality in the fine pitch gold wire bonding process, which has a small pad size of below 70um. The new method is based on a statistical approach and designed for the discrete Kalman filter. Real wire bonding experimental results are presented to demonstrate the advantages of the proposed algorithm.
A study on the Reliability Experiment and the Structural Improvement of Sliding Cover
Song Jun Yeob ; Kang Jae Hun ; Kim Tae Hyung ; Kim Ok Koo ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 146~154
Recently, the high-speed and intelligence technology of machine tools are developed for the high efficiency of productivity Under the operating condition from the high-speed of machine tools, the various failure modes can occur in core units of manufacturing system. Therefore it is for the reliability concept of machine tool to be required in a design level. And the above-stated technology must be accommodated in the feeding and spindle subsystem, etc those are the core units of machine tools. In this study, we are developed the test-bed of sliding cover (C-plate) in order to evaluating reliability and estimating failure modes of feeding subsystem under operating conditions. The reliability experiment using the developed test-bed and the additional structural analysis executed on single and double structure. We found out the weak parts of sliding cover and were able to predict a life cycle from the experiment results. In this study, we propose the new C-plate model with double link structure to apply the high-speed machine tool in the fundamental guideline.
Temperature Control Improvement of Pressure Heating Roller for Flexible Flat Cable Production
Kim Jae Hak ; Lee Ho Jung ; Chun Keyoung Jin ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 155~163
Pressure heating rollers with temperature control were mounted to a flat cable laminating machine (FCLM). Pressure heating rollers should be heated up to the setting temperature
and kept on to producing good quality flexible flat cables (FFC). Existing Pressure heating rollers took more than 70minutes to the setting temperature and did not keep on the setting temperature in production. Temperature controller, electric power controller, material and diameter of rollers and heat capacities were changed to improve the temperature control of the pressure heat rollers for better production of the FFC. Thus, the reaching time to the setting temperature (RT), temperature stability time (TST) and temperature hunting (TH) were measured and compared with the existing pressure rollers case. The RT of A roller was shortened by 50minutes, and B roller was shortened by 15minutes. The TST of A roller was shortened by 13minutes, and B roller was shortened by 15minutes. The THs of both A and B rollers were settled up to
. Finally, the productivity of the FCLM and the quality of the FFC were increased.
Valuation and Improvement on Micro-gripper System by Axiomatic Design
Jeon Jong Hyup ; Park Jong Kyu ; Moon Won Kyu ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 164~169
The micro-gripper system is one of the systems that should be improved in the respect of performance for practical usage. In the previous works, the important issues are considered and presented using axiomatic design approach. In this paper, the functional requirements and design parameters are evaluated in order to improve the performance and efficiency of the system. The evaluation is a very difficult task since many variables are related to the outcomes. To provide a basis for correct design decisions, axiomatic design principles have been advanced. Since the framework of axiomatic design makes design issues easier to understand when they are analyzed, we used those as an evaluation tool. The object of the system is to handle micro-size parts. Main device is a micro-gripper using two bender-typed and one stack-typed PZTs as actuators. And it has three tips made of tungsten wires fur holding function. Also the system must satisfy other functional requirements for appropriate handling performance. The results of this study show design improvements of micro-gripper system such as structural change of gripper, additional element, and integration of physical parts. Axiomatic design guides presented suitable design parameters corresponding to functional requirements and made the design elements improve through diagrams of whole system.
Evaluation of Effective Stiffness for 3D Beam with Repeated Structure
Chung Ilsup ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 170~176
Analysis of structures which are composed of numerous repeated unit structures can be simplified by using homogenized properties. If the unit structure is repeated in one direction, the whole structure may be regarded as a beam. Once the effective stiffness is obtained from the analysis of the unit structure in a proper way, the effort for the detail modeling of the global structure is not required, and the real structure can be replaced simply with a beam. This study proposes a kinematical periodicity constraint to be imposed on the FE model of the unit structure, which improves the accuracy of the effective stiffness. The method is employed to a one dimensionally arrayed 3D structure containing periodically repeated un-symmetric holes. It is demonstrated that the deformation behavior of the homogenized beam agrees well with that of the real structure.
Optimization of an Electron Microwave Oven Window Injection Mold Using Kriging Based Approximation Model
Ryu M. R. ; Lee K. H. ; Kim Y. H. ; Park H. S. ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 177~184
Recently, the engineering designer of injection mould has become more and more dependent on the CAE. In the design factors of injection mould, the shrinkage rate should be considered as one of the important performances to produce the reliable products. therefore the shrinkage rate can be mostly calculated by the MoldFlow and Pro-engineering. in the design process. However it is not easy to predict the shrinkage rate of a plastic injection mold in its design process because the analysis can take minutes to hours, the high computational costs of performing the analysis limit their use in design optimization. In this study, the surrogate models, DACE model, based on the Kriging in order to optimize the shrinkage rate of electric microwave oven window is used in lieu of the original models, facilitating design optimization.
Electrical Stimulation System Design for Pharyngeal Dysfunction of Stroke Patients
Yoo Ji Hye ; Bae Ha Suk ; Choi Byoung Cheol ; Kim Sung Min ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 185~190
The purpose of this study is to design electrical stimulation system fur stroke patients with pharyngeal dysfunction(dysphagia). Dysphagia is that the food has trouble in passing to the mouth from the stomach. Although we have many treatment methods for dysphagia, electrical stimulation system will be useful for stroke patients having dysphagia. Electrical stimulation system can be divided into body and electrodes. The body stimulation is composed to frequency counter, time control and current measurement part. These parts are to control the frequency, stimulating time and current intensity And they can be variable according to the patient's clinical assessment. The electrode plays a role to deliver the current from the system to the muscle. Also the position of the electrode can be variable according to the treatment method. We performed the clinical experiment with stroke patients who had swallowing disorder. The videofluoroscopy was used fur the observation. From the result of clinical experiment based on electrical stimulation, we expected that the dysfunction(in pharynx) level of the patient could be improved. However we could not have enough effectiveness of the treatment because of the number of patients, patient's adaptation and treatment period. We will design the optimized electrical stimulation system based on enough clinical experiment in the future.
Geometrical Design Theory of a 6 DOF Vibration Absorber
Jang Seon Jun ; Choi Yong Je ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 191~199
Many researchers have been investigating the design of multi-mode absorption vibration absorber for multi degree-of-freedom (DOF) system. The approach taken to this problem has been to find the optimized constants of stiffness and damping for the given set of single-DOF absorbers or single multi-DOF absorber attached to a multi degree-of-freedom system. This paper presents a novel geometrical and direct design theory of a 6 DOF vibration absorber via screw theory. Theoretical development is demonstrated by a practical example in which the diagonal stiffness matrix is synthesized using rectangular configuration of springs. The performance of this absorber is simulated by modal analysis.
Correlation between Cognitive Performance Ability, Neural Activation Area and Neural Activation Intensity in fMRI
Sohn Jin Hun ; Oh Chong Hyun ; Tack Gye Rae ; Yi Jeong Han ; Lee Soo Yeol ; Chung Soon Cheol ;
Journal of the Korean Society for Precision Engineering, volume 22, issue 7, 2005, Pages 200~207
This study compares two different methods of measuring brain-BOLD activation. By comparing two different methods of measurement i.e., one method calculating the neural activation area (the number of activated voxels), while the other measured the neural activation intensity (the mean intensity of selected activated yokels), this study identified the more precise method of measuring brain activation which results from the completion of a visuospatial task. 16 right-handed male college students (mean age 23.2 years) participated in this study as subjects. Functional brain images were scanned on them using a 3T MRI single-shot EPI method. No correlation was found between the levels of cognitive performance and number of activated yokels in the activated brain areas. However, a significant correlation was found between the levels of cognitive performance and the mean intensity of selected activated yokels in the parietal, frontal, and other areas. In conclusion, the method of mean intensity was considered a better index of brain activity rather than the activated yokels measurement method.