Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society for Precision Engineering
Journal Basic Information
Journal DOI :
Korean Society of Precision Engineering
Editor in Chief :
Volume & Issues
Volume 33, Issue 9 - Sep 2016
Volume 33, Issue 8 - Aug 2016
Volume 33, Issue 7 - Jul 2016
Volume 33, Issue 6 - Jun 2016
Volume 33, Issue 5 - May 2016
Volume 33, Issue 4 - Apr 2016
Volume 33, Issue 3 - Mar 2016
Volume 33, Issue 2 - Feb 2016
Volume 33, Issue 1 - Jan 2016
Selecting the target year
Modeling of Various Tool Influence Functions in Computer Controlled Optical Surfacing
Kim, Gi-Chul ; Ghim, Young-Sik ; Rhee, Hyug-Gyo ; Kim, Hak-Sung ; Yang, Ho-Soon ; Lee, Yun-Woo ;
Journal of the Korean Society for Precision Engineering, volume 33, issue 3, 2016, Pages 167~172
DOI : 10.7736/KSPE.2016.33.3.167
The computer controlled optical surfacing (CCOS) technique provides superior fabrication performance for optical mirrors when compared to the conventional method, which relies heavily on the skill of the optician. The CCOS technique provides improvements in terms of mass production, low cost, and short polishing time, and are achieved by estimating and controlling the moving speed of the tool and toolpath through a numerical analysis of the tool influence function (TIF). Hence, the exact estimation of various TIFs is critical for high convergence rates and high form accuracy in the CCOS process. In this paper, we suggest a new model for TIFs, which can be applied for various tool shapes, different velocity distributions, and non-uniform tool pressure distributions. Our proposed TIFs were also verified by comparisons with experimental results. We anticipate that these new TIFs will have a major role in improving the form accuracy and shortening the polishing time by increasing the accuracy of the material removal rate.
Design of Clutch Mechanism for Increased Actuator Energy Efficiency of Electrically Actuated Lower Extremity Exoskeleton
Kim, Ho Jun ; Kim, Wan Soo ; Lim, Dong Hwan ; Han, Chang Soo ;
Journal of the Korean Society for Precision Engineering, volume 33, issue 3, 2016, Pages 173~181
DOI : 10.7736/KSPE.2016.33.3.173
This paper reports on the development of a roller-cam clutch mechanism. This mechanism can transfer bidirectional torque with high backdrivability, as well as increase actuation energy efficiency, in electrical exoskeleton robots. The developed mechanism was installed at the robot knee joint and unclutched during the swing phase which uses less metabolic energy, thereby functioning as a passive joint. The roller-cam clutch aimed to increase actuation energy efficiency while also producing high backdrivability by generating zero impedance for users during the swing phase. To develop the mechanism, mathematical modeling of the roller-cam clutch was conducted, with the design having more than three safety factors following optimization. Titanium (Ti-6AL-4V) material was used. Finally, modeling verification was done using ANSYS software.
Comparison of PID Controllers by Using Linear and Nonlinear Models for Control of Mobile Robot Driving System
Jang, Tae Ho ; Kim, Youngshik ; Kim, Hyeontae ;
Journal of the Korean Society for Precision Engineering, volume 33, issue 3, 2016, Pages 183~190
DOI : 10.7736/KSPE.2016.33.3.183
In this study, we conduct linear and nonlinear modeling of the DC motor driving system of a wheeled mobile robot, which is a nonlinear system involving dead zone, friction, and saturation. The DC motor driving system consists of a DC motor, a wheel, and gears. A linear DC motor driving system is modeled using a steady-state response and parameter measurements. A nonlinear DC motor driving model is identified with the use of the Hammerstein-Wiener method. By using these models, PID controllers for the DC motor system are then established. Each PID controller is applied as a low-level controller in order to achieve posture stabilization control for the real mobile robot. We also compare the performance of the proposed PID controllers in posture stabilization experiments by using several different final robot postures.
Feasibility Evaluation of End-to-End Application of Single Disposable UHF RFID Tags to Automotive Production Lines
Park, Kyujong ; Lee, Yong-Han ;
Journal of the Korean Society for Precision Engineering, volume 33, issue 3, 2016, Pages 191~198
DOI : 10.7736/KSPE.2016.33.3.191
Traceability is essential in modern automotive manufacturing. Among existing technologies, RFID is the most promising choice for this purpose. However, due to the harsh conditions of production lines, especially in the paint shop, automobile OEMs would require expensive dedicated RFID tags and readers, which are incompatible with standard RFID technologies. Unlike the manufacturing industry, the logistics industry uses UHF label tags for track and trace, which provides high performance and a low price. Recently, this technology has improved to the extent that it can be used in harsh conditions such as on metal parts or in liquid. Herein, we assess the technical, operational, and economic feasibility of UHF label-tag technology for seamless end-toend traceability. Based on prototyping, lab/field tests, and cost-benefit analysis, we have proven that the single disposable UHF tags can successfully replace the problematic and expensive tags used in most domestic automobile OEMs today.
Structural Design and Manufacturing of Corrugated Plate for Plate-Type Heat Exchanger
Yu, Jae Hyun ; Bae, Won Byong ; Park, Sang Hu ; Cho, Jong Rae ; Jeong, Ho Seung ;
Journal of the Korean Society for Precision Engineering, volume 33, issue 3, 2016, Pages 199~205
DOI : 10.7736/KSPE.2016.33.3.199
A thin sheet of metal with corrugated structures has been utilized in various devices: heat exchangers, separators in fuel cells, and many others. However, it is not easy to fabricate thin corrugated structures using a single-step stamping process due to their geometrical complexity. To solve this problem, firstly, a plate type heat exchanger was redesigned to attain the optimal value of aspect ratio and the optimal shape of corrugated structures for the actual loading conditions. A forming analysis of the corrugated plate was then carried out to determine the process parameters. From this work, the optimal value of aspect ratio was found to be 4.6. In addition, the process parameters of heat exchanger forming were optimized using the optimal value of aspect ratio, and the analytical results were evaluated through experiments. The results obtained indicated good agreements between them.
Performance Improvement of Oil Pump by Design of Gerotor (Combined Profile - Two Ellipses) and Port
Kwak, Hyo Seo ; Li, Sheng Huan ; Kim, Chul ;
Journal of the Korean Society for Precision Engineering, volume 33, issue 3, 2016, Pages 207~216
DOI : 10.7736/KSPE.2016.33.3.207
A gerotor is suitable for miniature manufacturing because it has high discharge per 1 cycle and a simple structure, while also being widely used for lubrication oil of engines and as a hydraulic source of automatic transmission. In the automobile industry, improvements in fuel efficiency and noise reduction have recently come to the fore. It has also been necessary to continuously improve the flow rate and noise of internal gear pumps for better fuel efficiency through optimal gerotor and port shape design. In this study, to develop an optimal gerotor with a new lobe shape, 2-ellipses-combined, the equation of the lobe shape was derived, and CFD analysis results were compared for 2-ellipses with those of the previous gerotors (3-ellipses and ellipse1-involuteellipse2). A performance test for the oil pump with the optimal rotor (2-ellipses) was carried out and showed good agreement with the results obtained from CFD analysis.
Movement of Liquid Metal Droplet in Channel by Continuous Electrowetting Effect
Baek, Seungbum ; Won, Dong-Joon ; Kim, Hojin ; Kim, Joonwon ;
Journal of the Korean Society for Precision Engineering, volume 33, issue 3, 2016, Pages 217~223
DOI : 10.7736/KSPE.2016.33.3.217
In this paper, the movement of a liquid metal droplet in a channel by continuous electrowetting effect is analyzed. The channel is fabricated using two glass substrates and silicone rubber as spacers, and a mercury droplet and dilute sulfuric acid are added into the channel. The droplet is moved according to voltage applied at both ends of the channel through an electrolyte. According to the shape of the droplet and the applied voltage, the velocity of the droplet is changed. The velocity is proportional to the applied voltage and inversely proportional to the length of the droplet, both theoretically and experimentally. Contact angle hysteresis and a meniscus change were also found in the moving state. This implies the existence of a threshold in movement by Laplace pressure difference. The experiment indicated that the sliding angle was inversely proportional to the width of the droplet but that the voltage threshold was proportional to the width.
Structures of Anodic Aluminum Oxide from Anodization with Various Temperatures, Electrical Potentials, and Basal Plane Surfaces
Kim, Yeongae ; Hwang, Woonbong ;
Journal of the Korean Society for Precision Engineering, volume 33, issue 3, 2016, Pages 225~230
DOI : 10.7736/KSPE.2016.33.3.225
Since the development of anodic aluminum oxide (AAO), extensive studies have been conducted ranging from fundamental research to the applications of AAO. Most of the research on AAO structures have focused on well-aligned nanoporous structures fabricated under specific conditions. This study investigated fabricable AAO structures with anodization performed with various temperatures, electrical potentials, and basal plane surfaces. As a result, nanoporous and nanofibrous structures were fabricated. The nanopores were formed at a relatively lower temperature and potential, and the nanofibers were formed at a relatively higher temperature and potential regardless of the basal plane surface. The shape of the base surface was found to influence the structural arrangement in nanoporous morphologies. These interesting findings relating to new morphologies have the potential to broaden the possible applications of AAO materials.
Study of Adhesion according to Various Surface Treatments for Lithium Ion Secondary Battery Pouch Film
Kim, Do Hyun ; Bae, Sung Woo ; Cho, Jung Min ; Yoo, Min Sook ; Kim, Dong Soo ;
Journal of the Korean Society for Precision Engineering, volume 33, issue 3, 2016, Pages 231~234
DOI : 10.7736/KSPE.2016.33.3.231
Pouch film is manufactured by laminating aluminum foil, polyamide film and polypropylene film with an adhesive or extrusion resin. However, a surface treatment is required for the aluminum because bonding does not occur easily between the aluminum foil and the polymer film. Thus, for this study, surface treatment experiments were performed in order to confirm the effect on adhesion strength. First, a variety of surface treatment solutions were coated on aluminum foil, and contact angle and surface morphology analysis was carried out for the surface-treated aluminum. For lamination of the surface-treated aluminum foil with polyamide film, a polyurethane base adhesive was prepared for the adhesive strength test specimens. The adhesive strength between the aluminum foil and the polyamide film of the resulting specimens was measured (UTM). With such an experiment, it was possible to evaluate the effect on adhesive strength of the various surface treatments.
Development of Hybrid-FDM Process Using Automatic Tool Changer for Multi-Material Production and Post-Processing
Choi, Sung Min ; Jian, Xiao ; Park, In Baek ; Lee, Seok Hee ;
Journal of the Korean Society for Precision Engineering, volume 33, issue 3, 2016, Pages 235~242
DOI : 10.7736/KSPE.2016.33.3.235
The purpose of this study is an attempt to improve the functionality of a conventional Fused Deposition Modeling (FDM) process using the Automatic Tool Changer (ATC) to perform multimaterial production and post-processing. Hybrid-FDM means a fusion of an Additive Manufacturing process and grinding process using the ATC system. In order to enhance the potentiality of production capacity for multi-material fabrication and surface roughness improvement, two extrusion tools and one grinding tool system are suggested. A pneumatic chuck is attached on a moving platform in the XY axes plane and an extrusion head and grinding head are placed in a docking station, allowing for a quick changeover with each other. Therefore, the manufacturing lead time can be reduced efficiently for the fabrication of a product.