This paper discusses flow characteristics of nanofluid minimum quantity lubrication (MQL) in the milling process of a titanium alloy by usingnumerical analysis. A mist of nanofluids including nanodiamond and hexagonal boron nitride (hBN) particles is sprayed into a tool-workpiece interface with conditions varying by spray angle and flow rate. The milling. Are experimentally measured and minimized by the determined optimal spray angle and flow rate. The subsequent numerical analysis based on a computational fluid dynamics (CFD) approach is conducted to calculate the penetration ratios of the nanofluid droplets into a tool. At the experimentally obtained optimal spray angle and flow rate of the nanofluids’ mist, the calculated ratio of penetration is highest and, therefore, the optimal spray conditions of the nanofluids are numerically validated.
Chemical mechanical polishing achieves surface planarity through combined mechanical and chemical means. The role of the chemical reaction is very important in a metal CMP like aluminum. The slurry used in aluminum CMP typically consists of oxidizers, a chelating agent, corrosion inhibitors, and abrasives. This study investigates the effect of oxalic acid as a chelating agent for aluminum CMP with H2O2. To study the chemical effect of the chelating agent, the two methods of a polishing experiment and an electrochemical analysis were used. Lastly, it was confirmed that the optimum concentration of oxalic acid significantly improved the removal rate and surface roughness of aluminum.
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Hybrid CMP Slurry Supply System Using Ionization and Atomization Hoseong Jo, Da Sol Lee, Seon Ho Jeong, Hyun Seop Lee, Hae Do Jeong Applied Sciences.2021; 11(5): 2217. CrossRef
Improvement of Interface Diffusion in Cu thin films using SiN/CoWB Passivation Layer Jung Woong Kim, Sean Jhin Yoon, Hyun Chan Kim, Youngmin Yun, Jaehwan Kim Journal of the Korean Society for Precision Engineering.2018; 35(12): 1163. CrossRef
To measure the depth of the through silicon vias on 300 mm silicon wafers, a measuring machine was developed. Based on the preceding research in a laboratory environment, the machine was designed and built by modifying the optical probe for reducing the mass, combining a visible optical microscope to monitor the location of the measuring points, and constructing the metrology frame for large silicon wafers. The depths of the three different-sized through silicon vias were measured repeatedly to estimate the repeatability. Moreover, comparative measurement was carried out to verify the measured depth values. The total measurement time was also estimated by measuring 110 through silicon vias at different locations. According to the measurement results, the measurement performance satisfied the technical requirements of the industry in terms of repeatability, accuracy, and measurement time.
This paper introduces a new outdoor localization method for practical application to guide robots. This method uses only encoder data from the robot’s wheels and non-inertial sensors, such as GPS and a digital compass, to guarantee ease of use and economy in real world usage without cumulative error. Position and orientation information from DGPS (Differential Global Positioning System) and a digital compass are combined with encoder data from the robot’s wheels to more accurately estimate robot position using an extended Kalman filter. Conventional robot guidance methods use different types of fusion that rely on DGPS. We use a very simple and consistent method that ensures localization stability by using the validation gate to evaluate DGPS reliability and digital compass data that can be easily degraded by various noise sources. Experimental results of the localization are presented that show the feasibility and effectiveness of the methods using a real robot in real world conditions.
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Indoor Localization of a Mobile Robot based on Unscented Kalman Filter Using Sonar Sensors Soo Hee Seo, Jong Hwan Lim Journal of the Korean Society for Precision Engineering.2021; 38(4): 245. CrossRef
Unscented Kalman Filter Based 3D Localization of Outdoor Mobile Robots Woo Seok Lee, Min Ho Choi, Jong Hwan Lim Journal of the Korean Society for Precision Engineering.2020; 37(5): 331. CrossRef
Estimation of Vertical Displacement based on Inertial Sensor Signals Combined with Joint Constraint Jung Keun Lee Journal of the Korean Society for Precision Engineering.2019; 36(3): 233. CrossRef
Kinematic Constraint-Projected Kalman Filter to Minimize Yaw Estimation Errors Induced by Magnetic Distortions Tae Hyeong Jeon, Jung Keun Lee Journal of the Korean Society for Precision Engineering.2019; 36(7): 659. CrossRef
Extended Kalman Filter Based 3D Localization Method for Outdoor Mobile Robots Woo Seok Lee, Min Ho Choi, Jong Hwan Lim Journal of the Korean Society for Precision Engineering.2019; 36(9): 851. CrossRef
Unscented Kalman Filter based Outdoor Localization of a Mobile Robot Woo Seok Lee, Jong Hwan Lim Journal of the Korean Society for Precision Engineering.2019; 36(2): 183. CrossRef
Dynamic Accuracy Improvement of a MEMS AHRS for Small UAVs Min-Shik Roh, Beom-Soo Kang International Journal of Precision Engineering and Manufacturing.2018; 19(10): 1457. CrossRef
Study on Robust Lateral Controller for Differential GPS-Based Autonomous Vehicles Hyung-Gyu Park, Kyoung-Kwan Ahn, Myeong-Kwan Park, Seok-Hee Lee International Journal of Precision Engineering and Manufacturing.2018; 19(3): 367. CrossRef
GPS-Based Human Tracking Methods for Outdoor Robots Woo Seok Lee, In Ho Cho, Jong Hwan Lim Journal of the Korean Society for Precision Engineering.2018; 35(4): 413. CrossRef
A depth image camera is used for efficient estimation of walking intention of a pedestrian. Three-Dimensional image coordinates of the pedestrian’s joints are obtained from the image data that includes depth information and are converted into the absolute coordinate values. The absolute coordinate data are classified and matched with all 20 joints of a pedestrian and the 9 joints that are corresponding the lower limbs are finally selected. After calculating each three-dimensional area of a triangle that was formed with the adjacent 3 joints of the 9 lower limb joints, the centroid of all triangles along time is obtained. The walking intention, that includes the direction and the speed of walking, can be estimated with the change rate of this centroid. It is experimentally verified by comparing the distance that is measured with inertia moment unit and the distance that the calculated centroid is moving.
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Intelligent robotic walker with actively controlled human interaction Ihn-Sik Weon, Soon-Geul Lee ETRI Journal.2018; 40(4): 522. CrossRef
For this study, A vibration attenuation of the vibration absorber that is attached to the flight structures was carried out. Flight structures are stabilized to allow for operations in various operating environments; however, as the size and weight of the flight structures are reduced, to meet the requisite performance, the operating-environment-induced vibrations lead to a degraded operating performance; therefore, the reduction of these vibrations should lead to an increased operating performance. The vibration absorber includes a compliant energy-storage device, such as a spring, and is mass secured to the energy-storage device. In this study, the research to prepare the anti-vibration design of the flight structures was accomplished, and the vibration of the flight structures was analyzed using the finite element analysis; accordingly, a vibration experiment for the verification of the result of the finite element analysis was also conducted. Further, the design guidelines of a tuned mass damper were obtained.
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A study of Tuned Mass Damper (TMD) Application for Mass Imbalance and Vibration Reduction in Gimbal Systems for High-speed Maneuverable Vehicles Jun-Soo Kim, Dong-Kyun Lee, Jong-Kuk Lee, Hyeon-Jun Cho, Ji-in Jung Journal of the Korean Society for Precision Engineering.2024; 41(11): 857. CrossRef
In this study, the intention is the determination of the optimum laminate conditions for the improvement of the chemical resistance of the aluminum-pouch films that are widely used as a packaging material for the secondary battery. Here, the properties including the initial adhesive strength and the electrolyte resistance between the metal-film layer with aluminum and the sealant layer with cast polyprophylene (CPP) film were investigated. Regarding the lamination condition, the lamination temperature, speed, and pressure conditions were changed. A roll-to-roll dry lamination-coating system was used in the surface-treatment agent coating, adhesive coating, and film lamination. For the lamination conditions of the aluminum and CPP films, the initial adhesive strength of the laminated-pouch film manufactured with a 110oC temperature and a 6.0 M/min line speed is 1200 gf/15 mm. The measured adhesive strength of the 85oC electrolyte resistance after its immersion for 7 days is 600 gf/15 mm.
In this paper, we propose a simple and low-cost fabrication method for PMMA (Poly (Methyl Methacrylate)) acoustophoretic microfluidic chips using plasma-assisted bonding followed by MEMS (Microelectromechanical Systems) processes. A metal mold for replicating the PMMA polymer was fabricated using MEMS processes, and the microfluidic channel was imprinted on the PMMA polymer using a hot-embossing process. The closed fabricated microfluidic channel was achieved by means of the plasma-assisted bonding between the PMMA channel and the flat PMMA cover. The plasma treatment and hot-embossing conditions for PMMA-PMMA bonding were studied and evaluated. The particle separation test confirmed that the PMMA acoustophoretic microfluidic chips could be used. We expect the Si-based acoustophoretic microfluidic chip to be replaced by the presented polymer chip in such applications as blood or droplet separation.
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Fabrication of Acoustophoretic Device with Lateral Polymer Wall for Micro-Particle Separation Sungdong Kim, Su Jin Ji, Song-I Han, Arum Han, Young Hak Cho Journal of the Korean Society for Precision Engineering.2022; 39(5): 379. CrossRef
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Microchannel Fabrication on Glass Materials for Microfluidic Devices Jihong Hwang, Young Hak Cho, Min Soo Park, Bo Hyun Kim International Journal of Precision Engineering and Manufacturing.2019; 20(3): 479. CrossRef
Most of passive implants belong to medical device are consist of metallic and nonmetallic materials. According to the sort of components, it makes more influence into the human body. In this study, we performed induced-RF (Induced-Radio Frequency) heating evaluation which is part of MRI (Magnetic Resonance Imaging) compatibility and safety test and in-vivo pyrogen test with lumbar stand-alone cage. RF from 3T MRI coil was radiated on medical device, and provided heat nearby stand-alone cage. Thermal change detected areas are distinguished by metallic and nonmetallic part. As followed detection areas, febrility was shown and metallic part was slightly higher than control area, nonmetallic part. Furthermore, stand-alone cage was performed in accordance with in-vivo pyrogen test, and solution injected rabbits had no fever for test period. Through physically and biologically evaluated stand-alone cage, exothemic reaction was observed and we predicted the effect when it would be inserted in patient.
In the metal-cutting industry, energy prediction is important for environmentally-conscious manufacturing because it enables a numerical anticipation of the energy consumption from the input of the process parameters, and therefore it contributes to the increasing of the energy-efficiency of the machine-tool operations. This paper proposes an energy-prediction modeling approach for numerical-control programs based on historical machine-monitoring data that have been collected from machine-tool operations. The proposed approach can create accurate energy-prediction models that forecast the energy that is consumed by the execution of a numerical-control program. Also, it can create machine-specific energy-prediction models that accommodate the variety of shop-floor machining contexts. For this purpose, it uses MTConnect to represent the machine-monitoring data to embody an interoperable data-collection environment regarding the shop floor. This paper also presents a case study to show the feasibility and practicability of the proposed approach.
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Automated DNA Extraction Monitoring System Based on MTConnect Technology Sang-Ho Han, Ae-Ja Park, Ah-Reum Park, Mun-Ho Ryu Applied Sciences.2021; 11(2): 684. CrossRef
A Hybrid Learning-based Predictive Process Planning Mechanism for Cyber-Physical Production Systems Seung-Jun Shin Journal of the Korean Society for Precision Engineering.2019; 36(4): 391. CrossRef
Development of Unified Interface for Multi-Vendors’ CNC Based on Machine State Model Joo Sung Yoon, Il Ha Park, Jin Ho Sohn, Hoen Jeong Kim Journal of the Korean Society for Precision Engineering.2018; 35(2): 151. CrossRef
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