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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Manufacturing Technology Engineers
Journal Basic Information
Journal DOI :
The Korean Society of Manufacturing Technology Engineers
Editor in Chief :
Volume & Issues
Volume 20, Issue 6 - Dec 2011
Volume 20, Issue 5 - Oct 2011
Volume 20, Issue 4 - Aug 2011
Volume 20, Issue 3 - Jun 2011
Volume 20, Issue 2 - Apr 2011
Volume 20, Issue 1 - Feb 2011
Selecting the target year
Design of a Robust Position Tracking Controller with Sliding Mode for a 6-DOF Micropositioning Stage
Moon, Jun-Hee ; Lee, Bong-Gu ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 121~128
As high precision industries such as semiconductor, TFT-LCD manufacturing and MEMS continue to grow, the demand for higher DOF precision stages has been increasing. In general, the stages should accommodate a prescribed range of payloads in order to position various precision manufacturing/inspection instruments. Therefore a nonlinear controller using sliding motion is developed, which bears mass perturbation and makes the upper plate of the stage move in 6 DOF. For the application of the nonlinear control, an observer is also developed based on expected noise covariance. To eliminate the steady state error of step response, integral terms are inserted into the state-space model. The linear term of the controller is designed using optimization scheme in which parameters can be weighted according to their physical significance, whereas the nonlinear term of the controller is designed using trial and error method. A comprehensive simulation study proves that the designed controller is robust against mass perturbation and completely eliminates steady state errors.
Small Hydrogen Regulator for Mobile Fuel Cells
Kim, Hyung-Jin ; Seo, Young-Ho ; Kim, Byeong-Hee ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 129~132
This paper presents small hydrogen regulator for the mobile fuel cell. Mobile fuel cell is generally classified into open-end type and dead-end type. In the open-end type, flow rate of hydrogen is constantly controlled, while pressure of hydrogen is constantly maintained in the dead-end type. Considering the efficiency and stability of the fuel usage, dead-end type is more suitable with mobile fuel cell. Mobile fuel cell operated by dead-end mode requires hydrogen regulator which controls the hydrogen pressure from 0.1bar to 0.5bar within 3% error. In this paper, small hydrogen regulator (volume of 2.6cc) was fabricated by stainless steel. Regulation characteristics was experimentally evaluated.
Development of Map Building Algorithm for Mobile Robot by Using RFID
Kim, Si-Seup ; Seon, Jeong-An ; Kee, Chang-Doo ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 133~138
RFID system can be used to improve object recognition, map building and localization for robot area. A novel method of indoor navigation system for a mobile robot is proposed using RFID technology. The mobile robot With a RFID reader and antenna is able to find what obstacles are located where in circumstance and can build the map similar to indoor circumstance by combining RFID information and distance data obtained from sensors. Using the map obtained, the mobile robot can avoid obstacles and finally reach the desired goal by
algorithm. 3D map which has the advantage of robot navigation and manipulation is able to be built using z dimension of products. The proposed robot navigation system is proved to apply for SLAM and path planning in unknown circumstance through numerous experiments.
Estimation of Defect Position on the Pipe Line by Inverse Problem
Park, Sung-Oan ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 139~144
This paper presents a boundary element application to determine the optimal impressed current densities at defect position on the pipe line. In this protection paint, enough current must be impressed to lower the potential distribution on the metal surface to the critical values. The optimal impressed current densities are determined in order to minimize the power supply for protection. This inverse problem was formulated by employing the boundary element method. Since the system of linear equations obtained was ill-conditioned, including singular value decomposition, conjugate gradient method were applied and the accuracies of these estimation. Several numerical examples are presented to demonstrate the practical applicability of the proposed method.
Joining of Zinc Coated Steel and Aluminum Alloy for Car Body
Lee, Woo-Ram ; Lee, Jung-Hyun ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 145~150
There is problem to reduce the car body weight for improving fuel consumption and
generation. As one of the solution, the multi material car body concept using aluminum alloys and high strength steels is proposed recently. Therefore, new welding processes by which these dissimilar material can be joined in high reliability and productivity are demanded. Laser spot welding was developed for joining of dissimilar metals. In the present work, Laser spot welding of zinc coated steel and aluminum alloy was investigated, and the process parameters were studied. Otherwise, the influences of process parameters on the weldability, the formation of intermetallic compound layer and the mechanical properties have been investigated. When intermetallic compound layer thickness was more than 1mm, specimen was failure in the interface.
The Moulding Analysis of Fuel Pressure Regulator to the Vehicle
Park, Chang-Sun ; Sung, Back-Sub ; Kim, Jae-Yeol ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 151~156
This study examined the casting analysis of fuel pressure regulator of LPI vehicles. We aims to predict all the phenomenon accompanied by flow and solidification in die casting, and maximize productivity and quality through optimal casting design. As a result of comparing Types A and B of casting design, it was found that the number of overflow affected flow, flowspeed and solidification temperature. And there was a minute difference between solidification temperatures at thick section of the spare parts. Solidification began at temperatures of
but after the casting was completed, temperatures at the center of the parts were
Temperature of molten metal showed optimal flow at temperature of
. It began to solidity around at
and to be cooled between
in high speed. When the process was analysed through a computer simulation, it was found that hardness of regulators manufactured through Type B of overflow was above
Study on the Behavior and Damage of Pedestrian at Car Body Impact
Cho, Jae-Ung ; Han, Moon-Sik ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 157~161
The study for traffic safety improvement is so necessary to minimize the wound of pedestrian at car impact as to prevent pedestrian from this accident. This study aims at analyzing the behavior affected by impact on which car body hits pedestrian. Load and damage of pedestrian are also investigated. This model is the small car body as frame structure. The pedestrian is modeled with dummy by CATIA as Korean standard body style. The ear impacts the side of pedestrian with the speed from 30 to 90km/h. Behavior and damage of pedestrian at impact are analyzed by ANSYS. In case of 30km/h, The maximum pressure of dummy becomes the maximum value of 100MPa after the elapsed time of 0.1second and then seems to remain at 105MPa constantly. In case of 60km/h, its pressure becomes the maximum value of 110MPa at the elapsed time of 0.05second and decreases at 90MPa until the elapsed time of 0.1second. This value fluctuates after the elapsed time of 0.1second. In case of 90km/h, its maximum pressure becomes the maximum value of 155MPa at the elapsed time of 0.07second and fluctuates after the elapsed time of 0.07second until O.3second. This value seems to remain at 100MPa constantly after 0.3second until 0.5second. But this pressure increases suddenly just after 0.5second. Maximum deformations of dummy increase linearly according to elapsed time at hitting velocities of 30, 60 and 90km/h.
Enhancement of Wear Resistance by Low Heat Treatment and the Plasma Source Ion Implantation of Tungsten Carbide Tool
Kang, Seong-Ki ; Wang, Duck-Hyun ; Kim, Won-Il ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 162~168
In this research, nitrogen plasma source ion implantation(PSII) of non-coated tungsten carbide endmill tools was conducted with low heat treatment for increasing wear resistance. After the low heat treatment of PSIIed tools to give a homogeneity of wear resistance, the surface modification of tools was analyzed by hardness test, surface roughness and cutting forces. As for the resultant cutting forces, low heat treatment in temperature of
is stable because of low cutting resistance. The 20-minutes heat treated tool at spindle speed 25000rpm has superiority of surface roughness, Ra of
and was found to have good wear resistance. The higher hardness value was obtained by increasing temperature from
for PSIIed tools with low heat treatment. As the PSIIed tools under 10minutes at temperature of
have the highest hardness as Hv of 2349.8, It was analyzed that temperature processing give much influences on hardness.
Shape Design of Crash Box with Absorption Performance against Impact
Cho, Jae-Ung ; Han, Moon-Sik ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 169~173
Crash box is introduced to vehicle design to improve the impact performance and reduce the damage of vehicle body at impact speed. The crash box behind bumper can absorb impact energy effectively to improve vehicle safety. Repair cost at collision accident can be cut down by use of this box. The configuration of car body must be designed by considering the characteristic of material due to the deformation of car body happened at impact. Many papers have been published about material of crash box all over the world. The study of crash box with tube expansion type has been going on Korea. This study is done by the simulation analysis about front collisions against 5 kinds of aluminum crash boxes with the basic structure of square section.
Tool-Path Optimization of Magnetic Abrasive Polishing Using Heuristic Algorithm
Kim, Sang-Oh ; You, Man-Hee ; Kwak, Jae-Seob ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 174~179
This paper focuses on the optimal step-over value for magnetic tool path. Since magnetic flux density is changed according to distance from center of magnetic tool. Enhanced surface roughness is also different according to change of radius. Therefore, to get a identical surface roughness on workpiece, it is necessary to find optimal tool path including step-over. In this study, response surface models for surface roughness according to change of radiuses were developed, and then optimal enhanced surface roughness for each radius was selected using genetic algorithm and simulated annealing to investigate relation between radius and surface roughness. As a result, it found that step-over value of 6.6mm is suitable for MAP of magnesium alloy.
Micro Hole Machining by EDM Using Insulated Tool Combined with Ultrasonic Vibration of Dielectric Fluid
Park, Min-Soo ; Chung, Do-Kwan ; Lee, Kang-Hee ; Chu, Chong-Nam ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 180~186
This paper describes a micro electrical discharge machining (MEDM) technique that uses an insulated tool in combination with ultrasonic vibration to drill micro holes. As the machining depth becomes deeper, the dispersion of debris and circulation of the dielectric fluid are difficult to occur. Consequently, machining becomes unstable in the machining region and unnecessary electrochemical dissolution and secondary discharge sparking occur at the tool side face. To reduce the amount of unnecessary side machining, an insulated tool was used. Ultrasonic vibration was applied to the MEDM work fluid to better remove debris. Through these methods, a
thick stainless steel plate was machined by using a
diameter electrode. The diameters of the hole entrance and exit were
, respectively. It took only 351s to completely drill one hole.
A Study on Evaluation of Shear Strength for Pb-free Solder Joint with Ni-P/Au UBM
Cho, Seong-Keun ; Yang, Sung-Mo ; Yu, Hyo-Sun ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 187~192
UBM(Under Bump Metallurgy) is very important for successful realization of Flip-Chip technology. In this study, it is investigated the interfacial reactions between various Sn-Ag solder alloys and Ni-P/Au UBM and Cu plate finish. It is also evaluated the shear strength by using the micro shear-punch test method for Sn-37Pb alloy, binary and ternary alloys of environment-friendly Pb-free solder alloys which are applied in the electronic packages. In terms of interfacial microstructure, the Pb-free solder joints have thicker IMCs than the Sn-Pb solder joints. The thickness of IMC is related to Reflow time. The IMC has been observed to grow with the increase in Reflow time. As a result of the shear test, in case of Max. shear strength, Pb-free solder showed the highest strength value and Sn-37Pb showed the lowest strength value 10 be generally condition of Reflow time.
Board-Level Drop Analyses having the Flip Chips with Solder balls of Sn-3.0Ag-0.5Cu and Sn-1.0Ag-0.5Cu
Kim, Seong-Keol ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 193~201
Recently, mechanical reliabilities including a drop test have been a hot issue. In this paper, solder balls with new components which are Sn-3.0Ag-0.5Cu and Sn-1.0Ag-0.5Cu-0.05N are introduced, and board level drop test for them are conducted under JEDEC standard in which the board with 15 flip chips is dropped as 1,500g acceleration during 0.5ms. The drop simulations are studied by using a implicit method in the ANSYS LS-DYNA, and modal analysis is made. Through both analyses, the solder balls with new components are evaluated under the drop. It is found that the maximum stress of each chip is occurred between the solder ball and the PCB, and the highest value among the maximum stresses in the chips is occurred on the chip nearest to fixed holes on the board in the drop tests and simulations.
Evaluation of Bending Characteristics for Carbon FRP Structure having Circle Cross-section
Kim, Jung-Ho ; Kim, Ji-Hoon ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 202~206
Works on the strength and stiffness in the structural members are carried out widely with various material and cross-sections with ever increasing safety concerns, they are presently applied in various fields including railroad trains, air crafts and automobiles. In addition to this, problem of lighting structural members became important subject by control of exhaust gas emission, fuel economy and energy efficiency. So, Light weight of member structures is necessary for the high performance and various functions. In this study, the CFRP flat and circular member was manufactured by CFRP prepreg sheet in autoclave. Carbon FRP is an anisotropy material whose mechanical properties change with its fiber orientation angle, so this study apply to the effects of the fiber orientation angle on the bending characteristics of the member. Each CFRP flat and circle are compared by strength and stiffness.
Real-Time Implementation of Wireless Remote Control of Mobile Robot Based-on Speech Recognition Command
Shim, Byoung-Kyun ; Han, Sung-Hyun ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 207~213
In this paper, we present a study on the real-time implementation of mobile robot to which the interactive voice recognition technique is applied. The speech command utters the sentential connected word and asserted through the wireless remote control system. We implement an automatic distance speech command recognition system for voice-enabled services interactively. We construct a baseline automatic speech command recognition system, where acoustic models are trained from speech utterances spoken by a microphone. In order to improve the performance of the baseline automatic speech recognition system, the acoustic models are adapted to adjust the spectral characteristics of speech according to different microphones and the environmental mismatches between cross talking and distance speech. We illustrate the performance of the developed speech recognition system by experiments. As a result, it is illustrated that the average rates of proposed speech recognition system shows about 95% above.
Development of Automotive Lower Ann using Hybrid Manufacturing Process
So, Sang-Woo ; Hwang, Hyun-Tae ; Lee, Jong-Hyun ; Choi, Hung-Won ;
Journal of the Korean Society of Manufacturing Technology Engineers, volume 20, issue 2, 2011, Pages 214~218
In order to survive in turbulent and competitive markets, automotive part manufacturers try efforts to develop new manufacturing technologies for ultra-lightweight, high-intensity and environmentally-friendly parts. Most of front lower arm is manufactured by welding process between upper- and lower panel which are produced by press stamping process. Because lower arm mounted on the cross member parts is one of the important complementary parts. So, to improve safety and lightweight of these parts, hybrid technologies are used in this paper. As hybrid technologies are applied to be front sub-frame, rear cross member and other chassis parts as well as front lower arm, the 20% lightweight has been achieved compared with existing steel parts.