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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
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Journal DOI :
The Korean Society of Manufacturing Technology Engineers
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Volume & Issues
Volume 23, Issue 6 - Dec 2014
Volume 23, Issue 5 - Oct 2014
Volume 23, Issue 4 - Aug 2014
Volume 23, Issue 3 - Jun 2014
Volume 23, Issue 2 - Apr 2014
Volume 23, Issue 1 - Feb 2014
Selecting the target year
Signal Acquisition for Effective Prediction of Chatter Vibration in Milling Processes
Jo, M.H. ; Kim, H. ; Koo, J.Y. ; Lee, J.H. ; Kim, Jeong Suk ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 325~329
DOI : 10.7735/ksmte.2014.23.4.325
This paper proposes a method to predict chatter vibration generated in milling processes and to enhance machining quality and surface finish. Chatter vibration is a common problem in the milling of thin walls and floors. It causes a poor surface finish, or even marks, to appear on the final machined surface. Therefore, an effective method is necessary to predict chatter vibration in machine tools. In this investigation, chatter vibration is measured by an accelerometer, microphone, and Acoustic Emission (AE) sensor in a machining operation. Based on the results of the experiment, a microphone can be applied for the prediction of chatter vibration in milling processes.
Chip Shape Control using AE Signal in Pure Copper Turning
Oh, Jeong Kyu ; Kim, Pyeong Ho ; Koo, Joon Young ; Kim, Duck Whan ; Kim, Jeong Suk ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 330~336
DOI : 10.7735/ksmte.2014.23.4.330
The continuous chip generated in cutting process deteriorates workpiece, tool, and machine tool system. It is necessary to treat this continuous chip in ductile material machining condition for stable cutting. This paper deals with the chip control method using acoustic emission(AE) signal in pure copper turning operation. AE raw signals, root mean square(RMS) signals and wavelet transformed signals measured in turning process are introduced to analysis for chip patterns. With analysis of AE signals, it is obtained that the produced chip patterns are correlated with the specified AE signals which are transformed by fuzzy pattern algorithm. By this experimental investigation, the chip patterns can be classified at significant level in pure copper machining process and controlled from continuous chips to reduced-length stable chips.
A Jacobian Update-Free Newton`s Method for Efficient Real-Time Vehicle Simulation
Kang, Jong Su ; Lim, Jun Hyun ; Bae, Dae Sung ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 337~344
DOI : 10.7735/ksmte.2014.23.4.337
While implicit integration methods such as Newton`s method have excellent stability for the analysis of stiff and constrained mechanical systems, they have the drawback that the evaluation and LU-factorization of the system Jacobian matrix required at every time step are time-consuming. This paper proposes a Jacobian update-free Newton`s method in order to overcome these defects. Because the motions of all bodies in a vehicle model are limited with respect to the chassis body, the equations are formulated with respect to the moving chassis-body reference frame instead of the fixed inertial reference frame. This makes the system Jacobian remain nearly constant, and thus allows the Newton`s method to be free from the Jacobian update. Consequently, the proposed method significantly decreases the computational cost of the vehicle dynamic simulation. This paper provides detailed generalized formulation procedures for the equations of motion, constraint equations, and generalized forces of the proposed method.
Mechanical Characteristic Evaluation by Spin Tool of Different Pin Shapes in Friction Stir Welding Al6061-T6
Lim, ByungChul ; Kim, DaeHwan ; Park, SangHeup ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 345~349
DOI : 10.7735/ksmte.2014.23.4.345
In this study, an age-hardened 6061-T6 alloy sheet was used, which is commonly utilized for auto parts. The junction strength characteristics in relation to the stirring speed and welding speed were studied in accordance with the friction stir welding rotation of the tool pin. Micro hardness measurements of A type and B type pins, for a welding speed of 400 mm/min and a tool rotational speed 3000 rpm, were obtained as Hv104 and Hv111, respectively. For a welding speed of 200 mm/min and a tool rotational speed of 2000 rpm, we obtained Hv48 and Hv50 for A and B type pins, respectively. Microstructure observation showed that the stirring portion was fine and uniform, which occurred because of its plastic deformation. In the thermomechanically affected zone, partial recrystallization was present because of the plastic deformation. The crystal grains in the heat affected zone were coarsened due to the heat generated by friction stir welding.
Bead Optimization to Reduce Springback of Sheet Metal Forming using High Strength Steel
Hong, Seokmoo ; Hwang, Jihoon ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 350~354
DOI : 10.7735/ksmte.2014.23.4.350
Recently, high strength steel (HSS) sheet metal has been widely used to improve lightweight structures in the automotive industry. Because HSS sheets have high strength but low elongation, it is difficult both to make products with complex shapes and to control excessive springback. In order to reduce the springback after forming using HSS, draw beads were introduced in this study. The design variables, including the draw-bead positions and shapes, were optimized using a finite element analysis. A mold for a scanner support, which is part of an A3 printer, was designed using the proposed method and then utilized. The results from a finite element simulation and optimization were compared with the experiment results.
Thermo-ompression Process for High Power LEDs
Han, Jun-Mo ; Seo, In-Jae ; Ahn, Yoomin ; Ko, Youn-Sung ; Kim, Tae-Heon ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 355~360
DOI : 10.7735/ksmte.2014.23.4.355
Recently, the use of LED is increasing. This paper presents the new package process of thermal compression bonding using metal layered LED chip for the high power LED device. Effective thermal dissipation, which is required in the high power LED device, is achieved by eutectic/flip chip bonding method using metal bond layer on a LED chip. In this study, the process condition for the LED eutectic die bonder system is proposed by using the analysis program, and some experimental results are compared with those obtained using a DST (Die Shear Tester) to illustrate the reliability of the proposed process condition. The cause of bonding failures in the proposed process is also investigated experimentally.
Development of Rotational Nanoactuator Based on Four-Bar Linkage
Jeong, Young Hun ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 361~367
DOI : 10.7735/ksmte.2014.23.4.361
Ultra-precision positioning plays a crucial role in emerging technologies such as electronics, bioengineering, optics, and various nanofabrication technologies. As a result, various nanopositioning methods have been presented. In particular, nanopositioning using a flexure mechanism and piezo-electric actuator is one of the most valuable methods because of its friction-free motion and subnanometer-scale motion resolution. In this study, a rotational nanoactuator based on a right-circular flexure mechanism and piezo-electric actuator was developed through a consideration of the kinematics and structural deformation. An experimental setup was constructed to verify the performance expectation. Consequently, it was demonstrated that the developed system had a maximum rotational angle of about 0.01 rad, as well as sufficient linearity with respect to the input voltage.
Dynamic Analysis of Spindle with Angular Contact Ball Bearings Subjected to Angular Misalignment
Bae, Gyu-Hyun ; Hong, Seong-Wook ; Yoon, Young-Seok ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 368~373
DOI : 10.7735/ksmte.2014.23.4.368
This paper presents the dynamic modeling and analysis results for a spindle supported by angular contact ball bearings (ACBBs) subjected to angular misalignment. Although ACBBs are widely used in spindle systems, their characteristics in regard to angular misalignment have rarely been investigated. A simulation program was developed to calculate the dynamic characteristics of a simple spindle model that is supported by angular contact ball bearings subjected to angular misalignment. Angular misalignment is shown to introduce anisotropy into the angular contact ball bearings and then split the natural frequencies in spindles. Simulations were also performed to show the possibility of evaluating bearing misalignment using natural frequency measurements.
Mobile Performance Evaluation of Mecanum Wheeled Omni-directional Mobile Robot
Chu, Baeksuk ; Sung, Young Whee ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 374~379
DOI : 10.7735/ksmte.2014.23.4.374
Mobile robots with omni-directional wheels can generate instant omni-directional motion without requiring extra space to change the direction of the body. Therefore, they are capable of moving in an arbitrary direction under any orientation even in narrow aisles or tight areas. In this research, an omni-directional mobile robot based on Mecanum wheels was developed to achieve omni-directionality. A CompactRIO embedded real-time controller and C series motion and I/O modules were employed in the control system design. Ultrasonic sensors installed on the front and lateral sides were utilized to measure the distance between the mobile robot and the side wall of a workspace. Through intensive experiments, a performance evaluation of the mobile robot was conducted to confirm its feasibility for industrial purposes. Mobility, omni-directionality, climbing capacity, and tracking performance of a squared trajectory were selected as performance indices to assess the omni-directional mobile robot.
Noise Reduction in Tractor Cabin
Kim, Wonjin ; Eun, Myoungwoo ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 380~384
DOI : 10.7735/ksmte.2014.23.4.380
This study focused on identifying the major noise source in a tractor cabin using experimental methods. The noise levels in a tractor cabin for different engine revolution speeds were analyzed to identify the noise source. The results showed that the power steering unit (PSU) was the major noise source in a tractor cabin. The PSU was moved to the outside from the inside of the cabin in order to reduce the noise in the tractor cabin. As a result, the noise levels on the left and right sides of the operator in the tractor cabin were reduced by 6.8 and 3.9 dB, respectively. Finally, the window method was introduced to evaluate the contribution of the transmission noise. The orders of significance in the tractor noise were the front, bottom, and left area, successively.
Development of Control System for Ultrasonic Spray Pyrolysis Deposition
Kim, Kyu-Eon ; Kim, Yeong-Heum ; Lee, Chibum ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 385~391
DOI : 10.7735/ksmte.2014.23.4.385
A control system for ultrasonic spray pyrolysis deposition was developed that can coat a large size glass panel with a transparent conductive oxide. It consists of several ultrasonic atomizer devices to cover a large area and a host computer for individually controlling the devices. The sub-controller in an ultrasonic atomizer device can adjust the flow rate of the atomized conductive oxide gas by setting the flow rate of the solution and regulating the level of the solution in the tank. To construct a feedback control loop for level regulation, a level sensor that utilized an infrared distance sensor and an electric circuit for adjusting the ultrasonic oscillator were developed. The host program was also developed, which can monitor and control the sub-controllers. A proportional-integral controller was developed for a simplified model, and its operation was verified through an experiment.
Experimental Control Characteristic Investigation of Ball Bearing Guided Linear Motion Stage with Diamond-like Carbon Coated Guide Rail
Shim, Jongyoup ; Khim, Gyungho ; Hwang, Jooho ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 392~397
DOI : 10.7735/ksmte.2014.23.4.392
Recently, there is an increase in the need for precision linear stages with vacuum compatibility in such areas as lithography equipment for wafer or mask manufacturing, mask mastering equipment for optical data storage and electron beam equipment. A simple design, high stiffness and low cost can be achieved by using ball bearings. However, a ball bearing have friction and wear problems just as in ambient air. In order to decrease the friction, a special finish, a diamond-like carbon (DLC) film coating, is applied to the surface of a guide rail by sputtering deposition. This paper presents the result of an experimental investigation on the control performance of a ball bearing-guided linear motion stage under two environmental conditions: in air and vacuum. A comparison between the results with and without the DLC coating was also considered in the experimental investigation.
Optimization Design of Dry Adhesion for Wall-Climbing Robot on Various Curvatures Based on Experiment
Liu, Yanheng ; Shin, Myeongseok ; Seo, TaeWon ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 398~402
DOI : 10.7735/ksmte.2014.23.4.398
This paper presents the results of a study on the optimal footpad design for vertical climbing on acrylic surfaces with various curvatures used Taguchi methods. For a climbing robot, the adhesion system plays an important role in the climbing process. Only an appropriate adhesion strength will prevent the robot from falling and allow it to climb normally. Therefore, the footpad is a significant parameter for a climbing robot and should be studied. Taguchi methods were used to obtain a robust optimal design, where the design variables were the flat tacky elastomeric shape, area, thickness, and foam thickness of the footpad. Experiments were conducted using acrylic surfaces with various curvatures. An optimized footpad was selected based on the results of the experiments and analysis, and the stability of the wall-climbing robot was verified.
Robust Optimum Design of Resonance Linear Electric Generator for Vehicle Suspension
Choi, Ji Hyun ; Kim, Jin Ho ; Park, Sang-Shin ; Seo, TaeWon ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 403~407
DOI : 10.7735/ksmte.2014.23.4.403
To use vibration energy to generate electricity, a resonance vertical linear electric generator was applied to the suspension of a vehicle in a previous paper. However, the working conditions, including mass change in the vehicle body related to the cargo on board, number of passengers and the temperature difference caused by the operating environment, can influence the permanent magnet, which is the main component of the electric generator. Therefore, a robust optimum design is required to minimize the influences from the diverse operation conditions and maximize the electromotive force of the electric generator. In this paper, a resonance linear electric generator is introduced. Vibration response analysis to find the input velocity of the electric generator and an electromagnetic transient analysis to apply changes in the performance of the permanent magnet are performed. Finally, the optimum value of each design variable is derived using a Taguchi method.
Optimal Parametric Design of Coil Gun to Improve Muzzle Velocity
Lee, Su-Jeong ; Lee, Ju Hee ; Lee, Dong Yeon ; Seo, TaeWon ; Kim, Jin Ho ;
Journal of The Korean Society of Manufacturing Technology Engineers, volume 23, issue 4, 2014, Pages 408~412
DOI : 10.7735/ksmte.2014.23.4.408
An electromagnetic launching system presents a viable projectile propulsion alternative with low cost and minimal environmental drawbacks. A coil gun system propels a projectile using an electromagnetic force and the system is mainly employed in military weapon systems and space launch systems. In this paper, we perform optimization design to improve the muzzle velocity by analyzing the sensitivity. The muzzle velocity, which is the most important design function variable, is affected by design variables including the number of axial turns in the electromagnetic coil, number of radial turns in the electromagnetic coil, initial distance between the projectile and the coil, inner radius of the electromagnetic coil, and length of the projectile. An orthogonal arrays matrix is configured, and a finite element analysis is performed utilizing the commercial electromagnetic analysis software MAXWELL. The muzzle velocity of the optimal design is 62.4% greater than that of the initial design.