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Transactions of the Korean Society of Mechanical Engineers A
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Journal DOI :
The Korean Society of Mechanical Engineers
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Volume & Issues
Volume 34, Issue 12 - Dec 2010
Volume 34, Issue 11 - Nov 2010
Volume 34, Issue 10 - Oct 2010
Volume 34, Issue 9 - Sep 2010
Volume 34, Issue 8 - Aug 2010
Volume 34, Issue 7 - Jul 2010
Volume 34, Issue 6 - Jun 2010
Volume 34, Issue 5 - May 2010
Volume 34, Issue 4 - Apr 2010
Volume 34, Issue 3 - Mar 2010
Volume 34, Issue 2 - Feb 2010
Volume 34, Issue 1 - Jan 2010
Selecting the target year
Analysis of Durability of Torsion Beam Axle Using Modal Stress Recovery Method
Ko, Jun-Bok ; Lim, Young-Hoon ; Lee, Dong-Cheol ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1339~1344
DOI : 10.3795/KSME-A.2010.34.10.1339
MSM (Modal Superposition Method) is a technique for analyzing structural durability by taking the vibration characteristics into consideration. In this paper, MSR (Modal Stress Recovery) method, which is similar to MSM, was reviewed to check its validity as a durability analysis method. The MSR method directly calculates the modal displacement time history in multibody dynamics analysis; as a result, the total analysis time is shorter than that of MSM method. We conduct durability analysis using the MSR method and a durability test of a torsion beam axle that is affected by various road loads within the natural frequency of the beam axle. The analysis results for critical location and durability were in good agreement with the respective test results. Therefore, durability analysis using the MSR method is effective in predicting the durability of the structures of various dynamic systems.
Estimation of Joint Moment and Muscle Force in Lower Extremity During Sit-to-Stand Movement by Inverse Dynamics Analysis and by Electromyography
Kim, Yoon-Hyuk ; Phuong, Bui Thi Thanh ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1345~1350
DOI : 10.3795/KSME-A.2010.34.10.1345
Sit-to-stand movement is a basic movement in daily activities. On the basis of this movement, the biomechanical functions of a person can be evaluated. The study of the joint kinematics, moment, and muscle coordination is necessary to understand the characteristics of the sit-to-stand movement. We have developed a motion-based program for inverse dynamics analysis and the electromyogram-based program for muscle force prediction. The joint kinematics and the kinetic results estimated on the basis of obtained motion data, ground reaction force, and electromyogram signals were compared with those reported in previous studies, and the muscle forces determined by the two methods were compared with each other. The methods and programs developed in this study can be used to understand biomechanics and muscle coordination involved in basic movements in daily activities.
Study on Improving Reliability of Biomonitor by Using CCD Camera
Kim, Hyun-Chang ; Kim, Young-Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1351~1357
DOI : 10.3795/KSME-A.2010.34.10.1351
Water monitoring equipments using daphnia can be used to monitor the pollution levels of a country's main rivers. Such equipments should be capable of providing a prompt warning about increase in the contamination levels, which is evaluated on the basis of impulse number or toxicity index. As unmanned remote control equipments, they must provide reliable pollution monitoring results for each season and for the annual physical changes in each river. Two different equipments based on the impulse number and toxicity index showed different results for the operating rates and for the number of emergency checks required even though both were operated at the same conditions. The results are affected by many parameters such as the presence of any air bubbles and the microscopic pressure. The purpose of this study is to develop a method that can reduce the effect of bubbles or microscopic pressure on the monitoring data. We expect to achieve reliable monitoring data for water pollutants irrespective of the location of the equipment setup.
Study on Vehicle Deceleration Control in School Zones by Taking Driver's Comfort into Account
Cho, Hyo-Seung ; Kim, Hyoung-Seok ; Lee, Byung-Ryong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1359~1366
DOI : 10.3795/KSME-A.2010.34.10.1359
Recently, many electronic control techniques for vehicles have been developed and applied. One of the technologies can be X-by-wire such as throttle-by-wire, brake-by-wire, steer-by-wire, and etc, in which most of mechanical parts are replaced into electrical wire and actuators. In this study, the effect of throttle-by-wire and brake-by-wire control systems on vehicle velocity control, especially in a school zone, are taken into consideration. The number of accidents reported in school zones is higher than that in other places. The reason for this is that many vehicle drivers do not obey speed limit regulations. Moreover, some of the students are careless while crossing the streets. Therefore, in this study, we attempt to develop a method using throttle-by-wire and brake-by-wire control systems for automatically reducing the vehicle speed such that it will be within the speed limit. First, an engine model and a transmission system model are developed for a specific vehicle model. Second, speed reduction is carried out such that the reduction follows a pre-designed cubic spline trajectory; the trajectory is determined such that rapid deceleration, which causes discomfort to the driver and passengers, can be prevented, for which a fuzzy-PID control algorithm is applied for the trajectory following control. Finally, simulation results are presented to verify the performance of the proposed speed reduction control system.
Optimization of Resistance Spot Weld Condition for Single Lap Joint of Hot Stamped 22MnB5 by Taking Heating Temperature and Heating Time into Consideration
Choi, Hong-Seok ; Kim, Byung-Min ; Park, Geun-Hwan ; Lim, Woo-Seung ; Lee, Sun-Bong ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1367~1375
DOI : 10.3795/KSME-A.2010.34.10.1367
In this study, optimization of the process parameters of the resistance spot welding of a sheet of aluminum-coated boron alloyed steel, 22MnB5, used in hot stamping has been performed by a Taguchi method to increase the strength of the weld joint. The process parameters selected were current, electrode force, and weld time. The heating temperature and heating time of 22MnB5 are considered to be noise factors. It was known that the variation in the thickness of the intermetallic compound layer between the aluminum-coated layer and the substrate, which influences on the formation of nugget, was generated due to the difference of diffusion reaction according to heating conditions. From the results of spot weld experiment, the optimum weld condition was determined to be when the current, electrode force, and weld time were 8kA, 4kN, and 18 cycles, respectively. The result of a test performed to verify the optimized weld condition showed that the tensile strength of the weld joint was over 32kN, which is considerably higher than the required strength, i.e., 23kN.
Study on Inverse Approach to Validation of Viscoplastic Model of Sn37Pb Solder and Identification of Model Parameters
Gang, Jin-Hyuk ; Lee, Bong-Hee ; Choi, Joo-Ho ; Joo, Jin-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1377~1384
DOI : 10.3795/KSME-A.2010.34.10.1377
The objective of this study is to determine the best material model that represents the deformation behavior of the Sn37Pb solder alloy accurately. First, a specimen is fabricated and subjected to a thermal cycle with temperatures ranging from the room temperature to
. An experiment is conducted to examine deformation by Moire interferometry. Three different constitutive equation models are used in the finite element analysis (FEA) of the thermal cycle. In order to minimize the difference between the FEA results and the experimental results, the material parameters of the solder alloy are considered to be unknown and are determined by conducting optimization. As a result of the study, the Anand model is found to represent the deformation behavior of the solder most accurately.
Electromagnetic Flapping Shutters for Phone Cameras
Choi, Hyun-Young ; Han, Won ; Cho, Young-Ho ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1385~1391
DOI : 10.3795/KSME-A.2010.34.10.1385
In this study, we present small-size, low-power, and high-speed electromagnetic flapping shutters for phone cameras. These shutters are composed of trapezoidal twin blades suspended by H-type torsional springs. The existing electrostatic rolling and flapping shutters need high input voltage, while the existing electromagnetic rotating shutters are too big to be used for phone cameras. To achieve low-power and high-speed angle motion for small-size electromagnetic flapping shutters for camera phones, low-inertia trapezoidal twin blades, each suspended by the low-stiffness H-type torsional springs, are employed. The electromagnetic flapping shutters used in this experimental study have steady-state rotational angles of
in the magentic fields of 0.15 T and 0.30 T, respectively, for an input current of 60 mA; the maximum overshoot angles are
in the magentic fields of 0.15 T and 0.30 T, respectively. The rising/settling times of the shutter while opening are 1.0 ms/20.0 ms, while those while closing are 1.7 ms/10.3 ms. Thus, we experimentally demonstrated that the smallsize (
), low-power (
), and high-speed (~1/370 s) electromagnetic flapping shutters are suitable for phone cameras.
Correlation of Human Carpal Motion and Electromyogram
Chun, Han-Yong ; Kim, Jin-Oh ; Park, Kwang-Hun ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1393~1401
DOI : 10.3795/KSME-A.2010.34.10.1393
In this experimental study, we have examined the correlation between a human carpal motion and a surface electromyogram. The carpal motion patterns have been identified and the main muscles involved in the carpal motion have been determined by investigating the anatomical structure of a carpal. The torque acting against the carpal motion has been applied by using a device for carpal rehabilitation training, and the surface electromyogram signal corresponding to the torque at the main muscles has been measured. The root-mean-square (RMS) magnitude of the surface electromyogram signal has been calculated and used to analyze the correlation between the surface electromyogram signal and carpal motion. The experimental results have proved that for carpal torque values below
, the RMS magnitude of the surface electromyogram signal is linearly proportional to the carpal torque magnitude and that the carpal torque magnitude is linearly proportional to the cross-sectional area of the carpal muscles. Further, the analysis of the contribution of each muscle to the carpal motion has shown that the contribution of the most dominant muscle is consistently 60%. These three results can be applied to develop more sophisticated devices or robots for carpal rehabilitation training.
Low-Cycle Fatigue in Ni-Base Superalloy IN738LC at Elevated Temperature
Hwang, Kwon-Tae ; Kim, Jae-Hoon ; Yoo, Keun-Bong ; Lee, Han-Sang ; Yoo, Young-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1403~1409
DOI : 10.3795/KSME-A.2010.34.10.1403
For many years, high-strength nickel-base superalloys have been used to manufacture turbine blades because of their excellent performance at high temperatures. The prediction of fatigue life of superalloys is important for improving the efficiency of the turbine blades. In this study, low cycle fatigue tests are performed for different values of total strain and temperature. The relations between strain energy density and number of cycles before failure occurs are examined in order to predict the low cycle fatigue life of IN738LC super alloy. The results of low cycle fatigue lives predicted by strain energy methods are found to coincide with experimental data and with the results obtained by the Coffin-Manson method.
Evaluation of Variation in Residual Strength of Carbon Fiber Reinforced Plastic Plate with a Hole Subjected to Fatigue Load
Kim, Sang-Young ; Kang, Min-Sung ; Koo, Jae-Mean ; Seok, Chang-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1411~1417
DOI : 10.3795/KSME-A.2010.34.10.1411
CFRP (Carbon Fiber Reinforced Plastic) has received considerable attention in various fields as a structural material, because of its high specific strength, high specific stiffness, excellent design flexibility, favorable chemical properties, etc. Most products consisting of several parts are generally assembled by mechanical joining methods (using rivets, bolts, pins, etc.). Holes must be drilled in the parts to be joined, and the strength of the components subjected to static and fatigue loads caused by stress concentration must be decreased. In this study, we experimentally evaluated the variation in the residual strength of a holenotched CFRP plate subjected to fatigue load. We repeatedly subjected the hole-notched specimen to fatigue load for a certain number of cycles, and then we investigated the residual strength of the hole-notched specimen by performing the fracture test. From the results of the test, we can observe the initiation of a directional crack caused by the applied fatigue load. Further, we observed that the residual strength increases with a decrease in the notch effect due to this crack. It was evaluated that the residual strength increases to a certain level and subsequently decreases. This variation in the residual strength was represented by a simple equation by using a model of the decrease in residual strength for plain plate, which was developed by Reifsnider and a stress redistribution model for hole-notched plate, which was developed by Yip.
Low-Cycle Fatigue in Quenched Boron Steel Sheet Due to Hot Stamping
Jang, Won-Seok ; Suh, Chang-Hee ; Oh, Sang-Kyun ; Kim, Dong-Bae ; Sung, Jee-Hyun ; Jung, Yun-Chul ; Kim, Young-Suk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1419~1425
DOI : 10.3795/KSME-A.2010.34.10.1419
Boron steel sheet is suitable for fabricating automobile parts because it is very strong and has low weight. Recently, many car makers are investigating the feasibility of fabricating the chassis part of automobiles using boron steel. In order to use boron steel sheets to fabricate the chassis part of automobiles, much better material property of low cycle fatigue life as well as high formability during hot stamping is required. Therefore, the low-cycle fatigue life of hot-stamped quenched boron steel was investigated in this study. The fatigue life observed at low strain amplitude was longer than that of an as-received boron steel sheet. However, the fatigue life reduced at high strain amplitude because of the low ductility and low fracture toughness of martensite, which was produced as a result of hot stamping.
Study of a Mixed Finite Element Model for the Analysis of a Geometrically Nonlinear Plate
Kim, Woo-Ram ; Choi, Youn-Dae ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1427~1435
DOI : 10.3795/KSME-A.2010.34.10.1427
A mixed finite element model was developed using the classical plate theory to analyze the nonlinear bending of a plate. The appropriate weight functions for the constraints integrated over the domain were determined by the Lagrange multiplier method by using the principle of minimum virtual energy; which provides the constitutive relations between force-like variables and strains. All of detail terms of element wise coefficient matrices and associate tangent matrices to be used in the Newton iterative method are presented. Then, the linear solutions of the current model and those of the traditional displacement model under the SS (simple support) boundary conditions were compared with the existing analytical solution. The post-processed images of the nonlinear results of the force-like variables are presented to show the continuity of the solutions at the joint of the element boundaries. Finally, the converged nonlinear finite element solutions of the current model are compared with those of existing traditional displacement model.
Optimal Design of Slipper Metal for Power Transmission in Aluminum Hot Rolling Process
Lee, Hyun-Seung ; Lee, Young-Shin ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1437~1442
DOI : 10.3795/KSME-A.2010.34.10.1437
A slipper metal is used for power transmission in the aluminum hot rolling process. The slipper metal connects a spindle with a coupling. Therefore, if the slipper metal is seriously damaged, the spindle and the coupling will crash into each other. Therefore, preventing the destruction of the slipper metal is essential for ensuring a long mechanical life cycle. In this study, the structural analysis and optimal design of the slipper metal was carried out by finite element method for life extension of the slipper metal. To verify the interference of spindle assembly with modified slipper metal, a kinematics simulation was performed by applying various combinations of dynamic boundary conditions. As a result of structural analysis and optimal design of the slipper metal, the maximum stress of the modified slipper metal was lower than that of the initial model by 22%.
Pass Schedule Design to Inhibit Surface Cracks Generation on Workpiece in Groove Rolling Process
Na, Doo-Hyun ; Lee, Young-Seog ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1443~1453
DOI : 10.3795/KSME-A.2010.34.10.1443
We simulated the roughing train of the rod mill of SEAH BESTEEL Inc. using finite element method to inhibit surface cracks initiation on workpiece. We designed 2nd pass (square roll) and applied to this roll in the roughing train of the rod mill. Also, we proposed new pass schedule, which changed roll gap of 3rd and 4th groove by using finite element method. We used shear damage model, which is dependent on shear stress ratio and compared the number of damaged elements on workpiece. A damaged element means surface crack. Consequently, after 2nd pass (square roll) is changed, the error rate decreased by 1.43% when compare to that of the old groove. And the number of damaged elements in the new pass schedule decreased by 37.6%, which is less than present pass schedule.
High-Temperature Structural Analysis Model of the Process Heat Exchanger for Helium Gas Loop (II)
Song, Kee-Nam ; Lee, Heong-Yeon ; Kim, Chan-Soo ; Hong, Seong-Duk ; Park, Hong-Yoon ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1455~1462
DOI : 10.3795/KSME-A.2010.34.10.1455
PHE (Process Heat Exchanger) is a key component required to transfer heat energy of
generated in a VHTR (Very High Temperature Reactor) to the chemical reaction that yields a large quantity of hydrogen. Korea Atomic Energy Research Institute established the helium gas loop for the performance test of components, which are used in the VHTR, and they manufactured a PHE prototype to be tested in the loop. In this study, as part of the hightemperature structural-integrity evaluation of the PHE prototype, which is scheduled to be tested in the helium gas loop, we carried out high-temperature structural-analysis modeling, thermal analysis, and thermal expansion analysis of the PHE prototype. The results obtained in this study will be used to design the performance test setup for the PHE prototype.
Investigation on the Size Effects of Polycrystalline Metallic Materials in Microscale Deformation Processes
Kim, Hong-Seok ; Lee, Yong-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1463~1470
DOI : 10.3795/KSME-A.2010.34.10.1463
Microforming, which exploits the advantages of metal forming technology, appears very promising in manufacturing microparts since it enables the production of parts using various materials at a high production rate, it has high material utilization efficiency, and it facilitates the production of parts with excellent mechanical properties. However, the conventional macroscale forming process cannot be simply scaled down to the micro-scale process on the basis of the extensive results and know-how on the macroscale process. This is because a so-called "size effect" occurs as the part size decreases to the microscale. In this paper, we attempt to develop an effective analytical and experimental modeling technique for explaining the effects of the grain size and the specimen size on the behavior of metals in microscale deformation processes. Copper sheet specimens of different thicknesses were prepared and heat-treated to obtain various grain sizes for the experiments. Tensile tests were conducted to investigate the influence of specimen thickness and grain size on the flow stress of the material. In addition, an analytical model was developed on the basis of phenomenological experimental findings to quantify the effects of the grain size and the specimen size on the flow stress of the material in microscale and macroscale forming.
A Study of Friction in Microfoming Using Ring Compression Tests and Finite Element Analysis
Kim, Hong-Seok ; Kim, Geung-Rok ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1471~1478
DOI : 10.3795/KSME-A.2010.34.10.1471
Microforming processes have recently attracted considerable attention from industry and academia since they enable the production of microscale parts using various materials at a high production rate, minimize material loss, and provide parts with excellent mechanical properties. However, for successful development and applications of the microforming process it is critical to take the tribological size effect into consideration because previous studies have shown that traditional friction models for macroscale forming generate significantly erroneous results in the case of microforming. In this paper, we performed scaled ring compression experiments to investigate the tribological size effect of aluminum and brass materials in microforming. The sensitivity of the interfacial friction to the deformation characteristics of the ring was quantitatively analyzed by the finite element analysis. In addition, a friction model based on slip line field and upper boundary techniques was used to theoretically explain the friction mechanism in microforming.
Prediction of Axial Residual Stress in Drawn High-Carbon Wire Resulting Due to Increase in Surface Temperature
Kim, Dae-Woon ; Lee, Sang-Kon ; Kim, Byung-Min ; Jung, Jin-Young ; Ban, Deok-Young ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1479~1485
DOI : 10.3795/KSME-A.2010.34.10.1479
In recent times, due to wire drawing of high carbon steel at a high speed to ensure a high productivity and high strength, axial residual stress are generated because of rapid increase in surface temperature. In the process, the temperatures of the wires increased because of the deformation of the wires and the friction between the die and wire. In particular, in the case of the wire drawing at a high speed, friction leads to a large temperature gradient so that considerable axial residual stress is generated on the surface. In this study, the relationship between axial residual stress and increase in the surface temperature was investigated, and a prediction model of uniform temperature was proposed. Then, a prediction model for residual stress was developed. The proposed model was verified by measuring the residual stress by X-ray diffraction on drawn wires.
Design of Conformal Cooling Channels for the Mould of a Plastic Drawer of a Refrigerator by Analysis of Three-Dimensional Injection Moulding
Ahn, Dong-Gyu ; Park, Min-Woo ; Park, Seung-Hwa ; Kim, Hyung-Su ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1487~1492
DOI : 10.3795/KSME-A.2010.34.10.1487
The objective of this study is to design the conformal cooling channels for the mould of a plastic drawer of a refrigerator by analysis of three-dimensional injection molding. In order to obtain the desired design of the conformal cooling channels, the influence of the diameter and the position of the conformal cooling channels on the moulding characteristics and the product qualities were quantitatively examined. From the results of the examination, an optimal design of the conformal cooling channels, which ensures uniform cooling and minimum potential deformation of the molded drawers, was estimated. By comparing the designed mould and a conventional mould with linear cooling channels from the viewpoints of the product qualities as well as cooling and cycle times, it was shown that the mould with conformal cooling channels can simultaneously improve the productivity of the injection moulding process and the product qualities.
Experimental Study on Meso-Scale Milling Process Using Nanofluid Minimum Quantity Lubrication
Lee, P.H. ; Nam, T.S. ; Li, Chengjun ; Lee, S.W. ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1493~1498
DOI : 10.3795/KSME-A.2010.34.10.1493
This paper present the characteristics of micro- and meso-scale milling processes in which compressed cold air, minimum quantity lubrication (MQL) and
nanofluid MQL are used. For process characterization, the microand meso-scale milling experiments are conducted using desktop meso-scale machine tool system and the surface roughness is measured. The experimental results show that the use of compressed chilly air and nanofluid MQL in the micro- and meso-scale milling processes is effective in improving the surface finish.
Study on Performance Improvement in Magnetic Abrasive Polishing Assisted by Silicone Gel Medium
Kim, Sang-Oh ; Kwak, Jae-Seob ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1499~1505
DOI : 10.3795/KSME-A.2010.34.10.1499
In general, magnetic abrasive polishing can be used to effectively produce a mirror-like surface; however, industrial applications of this process involve some unsolved problems. For example, the polishing efficiency is low, and the used abrasives have to be treated. In this study, which is aimed at solving these problems, a novel medium of silicone gel, consisting of ferromagnetic particles and abrasives, is developed, and the effect of this medium is assessed on the basis of Taguchi's experimental method. The workpiece is a tungsten carbide steel and the surface roughness after magnetic abrasive polishing using the silicone gel is evaluated.
Study on the Relationship Between Emission Signals and Weld Defect for In-Process Monitoring in CO
Laser Welding of Zn-Coated Steel
Kim, Jong-Do ; Lee, Chang-Je ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1507~1512
DOI : 10.3795/KSME-A.2010.34.10.1507
In this study, the plasma induced by
laser lap welding of 6t Zn coated steel used for ship building was measured using photodiodes and a microphone. Then, the welding phenomenon with gap clearance of lap joint was compared with RMS-treated signal. Thus, we found that intensity of the RMS-treated signal increased with Zn vaporization; further, the presence of defects results in rapid variations with the RMS value as a function of lap-joint parameters. Besides, the FFT value of the raw signal with variations of changing welding parameters was calculated, and then the calculated FFT frequency value was set as the bandwidth of digital filter for a more accurate in-process monitoring. The RMS values were acquired by filtering the raw signal. By matching the weld beads and the calculated RMS values, we confirmed that there is a strong relationship between the signals and the defects.
Comparative Analysis of Injection Molding Process by On-line Monitoring in Cylinder of Injection Molding Machine and in Cavity of Mold
Park, Hyung-Pi ; Cha, Baeg-Soon ; Tae, Jun-Sung ; Choi, Jae-Hyuk ; Rhee, Byung-Ohk ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1513~1519
DOI : 10.3795/KSME-A.2010.34.10.1513
Recently, on-line process monitoring systems using sensors are being extensively used to produce highquality products. However, the difficulty in installing the sensors within the mold in the cases of micro-molds, optical molds, and molds with complex structures is a serious disadvantage of such process monitoring systems. In this study, the quantitative index of a process monitoring system was evaluated with the mold cavity pressure and the nozzle pressure for the injection molding machine. In order to evaluate the effect of the nozzle pressure, we performed correlation analysis for the weight of the molded product. We also examined the control characteristics of the injection molding machine by analyzing the effect of multistage injection speed, holding pressure, and injection pressure limit on the process monitoring data.
High-Speed Inkjet Monitoring Module for Jetting Failure Inspection
Shin, Dong-Youn ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1521~1527
DOI : 10.3795/KSME-A.2010.34.10.1521
Since inkjet printing is being employed in production lines of electronics and display industries, the tack time for inspection of jetting failure has become very important because the throughput of the inkjet printing system can be extended to the maximum limit by adopting a shorter jetting inspection time. The most popular method for inspecting jetting failure involves the use of a linear stage, a high magnification lens, and a charge coupled devicecamera. However, this conventional approach requires approximately 60 s to complete the jetting inspection and might not be suitable for a high-speed reciprocating jetting inspection in endurance tests due to the unwanted mechanical vibration. In this study, a novel concept of an inkjet monitoring module is introduced, which has an overall inspection time of 18 s. For the shorter tack time of jetting inspection, the parameters affecting the tack time are discussed in this paper.
Development of Methods for Detecting Inkjet Malfunction
Kwon, Kye-Si ; Go, Jung-Kook ; Kim, Jin-Won ; Kim, Dong-Soo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1529~1535
DOI : 10.3795/KSME-A.2010.34.10.1529
For the reliable use of inkjet technology as patterning tools, the jetting of the inkjet dispenser needs to be monitored for real-time detection of any malfunction. We present a self-sensing circuit that can be used to detect jetting failure by measuring electrical signals only. In addition, practical problems involved in the monitoring of inkjets in multinozzle printheads are discussed. In the study, software was developed and presented to demonstrate the feasibility of the proposed method for detecting inkjet jetting failure in a printing system.
Development of Inkjet Printing System for Printed Electronics
Kwon, Kye-Si ; Go, Jung-Kook ; Kim, Jin-Won ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1537~1541
DOI : 10.3795/KSME-A.2010.34.10.1537
An inkjet printing system for printed electronics was developed. In this study, a printing algorithm was mainly discussed. In order to print a pattern image at a target location, we developed a hardware and software algorithm for determining the distances between a substrate camera and the selected nozzles. We implemented a vector-printing algorithm where AutoCAD dxf file was used for XY motion control and for printing. We also developed printing method using bitmap images. The technical issues in using CAD drawings and bitmap images were discussed.
A Study of the FEM Forming Analysis of the Al Power Forging Piston
Kim, Ho-Yoon ; Park, Chul-Woo ; Kim, Hyun-Il ; Park, Kyung-Seo ; Kim, Young-Ho ; Joe, Ho-Sung ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1543~1548
DOI : 10.3795/KSME-A.2010.34.10.1543
Powder metallurgy processes are used to form Net-Shape products and have been widely used in the production of automobile parts to improve its manufacture productivity. Powder-forging technology is being developed rapidly because of its economic merits and because of the possibility of reducing the weight of automobile parts by replacing steel parts with aluminum ones, in particular while manufacturing automotive parts. In the powder-forging process, the products manufactured by powder metallurgy are forged in order to remove any pores inside them. Powderforging technology can help expand the applications of powder metallurgy; this is possible because powder-forging technology enables the minimization of flashes, reduction of the number of stages, and possible grain refinement. At present, powder forging is widely used for manufacturing primary mechanical parts as in combination with the technology of powder forging of aluminum alloy pistons.
Study on Improvement of Dimensional Accuracy of a Precision Plastic Screw Under Various Injection-Molding Conditions
Baek, Soon-Bo ; Park, Keun ; Youm, Chung-Ho ; Ra, Seung-Woo ;
Transactions of the Korean Society of Mechanical Engineers A, volume 34, issue 10, 2010, Pages 1549~1554
DOI : 10.3795/KSME-A.2010.34.10.1549
Recently, plastic screws have replaced metal screws because of the former's light weight, thermal and electrical insulating properties, and anticorrosion characteristics. Plastic screws are usually produced by injection molding, which involves material shrinkage during the solidification of the polymer. This shrinkage results in the degeneration of the dimensional accuracy. In the present study, the effect of injection-molding conditions on the dimensional accuracy of plastic screws was investigated through a numerical simulation of injection molding; on the basis of this simulation, we could determine the mold-design parameters. The design of experiment was applied in accordance with the numerical analysis in order to optimize the injection-molding conditions with a view to improving the dimensional accuracy of the precision plastic screw.