In modern society, industries are being upgraded in various fields. In particular, the defense industry has developed numerous technologies, such as the localization of core military technologies. The defense industry is actively studying technologies in areas such as in helicopters and tanks. In the case of radars, research on the radar itself is very active as is the research on the components that make up the radar. In this study, the temperature distribution of the two types of evacuation centers that make up the radar were analyzed using Computer Fluid Dynamics (CFD) to identify the temperature distribution based on the internal structure of the shelter. The two types of shelters have different heating values in different arrangements in the shelter provided they have the same size of heat source. Simulation results showed that the average temperature at the KA LNA shelter was different. In this study, we analyzed the effects of internal structure on the temperature and confirmed that the internal temperature may be decreased by changing the structure without using an external cooling element.
Gears are rotating mechanical parts with excellent power transmission efficiency and are widely used in machine tools, automobile, industrial machinery, and aviation industries. To enhance the performance of the gear, optimized design of the gear geometry is paramount. In this paper, we optimize the geometric tooth profile of helical gears which are among the gears of the transfer case gearbox by using the finite element program, Romax Designer to model and analyze the load and gear teeth of the gearbox power transmission system. The optimized gears were fabricated and compared to the results of the gear tests.
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Study on the Modification of the Contact Pattern and Teeth Shape of Tapping Device Drive Gears Sung-Min Moon, Yong-Woo Park, Do-Young Lee, Sung-Ki Lyu Journal of the Korean Society of Manufacturing Process Engineers.2025; 24(9): 76. CrossRef
Due to the ever-advancing technology in various production industries, the materials of machined products have been diversified from simple steel materials to composite materials, powder metallurgy materials and silicon. Powder metallurgy materials have excellent mechanical/chemical properties, but have disadvantages such as; difficulty in processing using conventional processing methods, increased processing cost and generation of a large amount of dust. In addition, the need for the development of specialized machine tools increases due to the disadvantages such as the frequent occurrence of burrs in tapping and drilling. In order to solve the problem of machining of high hardness sintered products, a method of maximizing productivity and efficiency by processing the powder metallurgy material before it is completely sintered is being studied. In this study, structural analysis of a turret center for the verification of structural stability of a turret center for processing powder metallurgy materials was carried out. In addition, the shape was optimized to improve the structural stability and weight and presented an optimal model. The study aimed at developing more reliable turret center through the optimized model.
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Automatic Measurement of Nanoimage Based on Machine Vision and Powder Metallurgy Materials Zhenghong Jiang, Chunrong Zhou, Haichang Zhang Advances in Materials Science and Engineering.2022; 2022: 1. CrossRef
Shape Optimization for Lightweight of the Metal 3D Printing Based Hybrid Machining Center Won-Young Jeong, Ho-In Jeong, Choon-Man Lee Journal of the Korean Society of Manufacturing Process Engineers.2021; 20(2): 80. CrossRef
Shape Optimization for Lightweight of the Line Center for Processing Complex Shape Parts Do-Hyun Park, Ho-In Jeong, Sang-Won Kim, Choon-Man Lee Journal of the Korean Society of Manufacturing Process Engineers.2021; 20(8): 86. CrossRef
Structural Safety of the Incinerator Transfer Conveyor Roller Chain Using GBO Bo-Ram Lee, Gyeong-Seop Park, Ill-Soo Kim Journal of the Korean Society of Manufacturing Technology Engineers.2020; 29(1): 9. CrossRef
In recent years, machinery industries such as aerospace and automotive industries have adopted high-precision machining. Cutting fluids increase the tool life and productivity through cooling and lubricating the machinery during processing. However, the cutting oil causes environmental pollution while the reuse of waste fluids negatively affects the tool life and machining quality. Therefore, it is important to study cutting oil environmental reuse methods and develop eco-friendly equipment such as a DC (Dust cake) filter system. In this study, the structural analysis was done using finite element method (FEM) to verify the stability and a study of the DC filter frame design improvementdone. Based on the damage on the DC filter system, the cause of the damage was assessed and an improvement to the structure suggested. Finally, the structural stability of the improved design was verified through analysis. The results of this analysis could be applied in order to further research.
Heat treated die steels are durable and resistant to abrasion. However, machining them is not very efficient. To improve the machinability using the end-milling process for high hardness die steels, we proposed an end-mill shape through analysis of the cutting force and simulation. In this study, we determined the important factors affecting the cutting force among several elements of end-mill shape using the customized cutting simulator and the design of experiments (DOE) technique. After the selecting the effective factors based on the simulation and DOE results, various end-mills were fabricated by adjusting the parameters. In the experiment, the cutting force between 1 pass and 40 pass were measured and the average value compared with each end-mill shape. Edge radius, radial relief angle and axial relief angle were selected as a key parameters and optimized by measuring the cutting force through repeated and well controlled experiments. In conclusion, the effective factors were confirmed and we could now determine the optimum shape of end-mill to minimize the cutting force for high hardness die steels.
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Diagnosis of Tool Wear and Fracture through Cutting Force Frequency Analysis of Stainless Steel Cutting End Mill Tools Tae Gyung Lee, Bo Wook Seo, Hwi Jun Son, Seok Kim, Young Tae Cho Journal of the Korean Society of Manufacturing Process Engineers.2023; 22(12): 88. CrossRef
Slot-die coating technique has become a subject of interest owing to its mass and large area production characteristics. To date, numerous research on the fluid dynamics of coated solution and experimental decision of the coating conditions to improve quality of coated layer have been conducted. However, few studies have been done on the optimization of slot-die coater geometry owing to the high cost associated with its fabrication. In this study, we optimize the geometry of the slotdie coater using computational fluid dynamics. We used a statistical optimization technique (Box-Behnken design). In the optimization process, we determined the significant factors that affect the velocity variation of coated fluid in the transverse direction. An optimal geometry was derived using a desirability test which is generally used to evaluate the suitability of a selected geometry value based on the maximization of the velocity uniformity. Experimental results presenting the uniformity of the coated layer in the transverse direction improved from 4.7% to 1.4%.
The production method of round wire used in conventional high-grade fabric production requires an additional step of cutting the side portion after cold rolling. However, after the additional cutting process, the performance of the round side portion was not improved. To solve these problems, the shape of the side portion is improved by replacing the process of wire cutting by the shape rolling. The rolling is done six times in total, and four flat rolling and two shape rolling are performed. There are three types of shape rolling: square, box and oval. The total number of cases of rolling analysis was analyzed nine times according to the kind of 3,5th shape rolling. Efficient shape rolling was selected by comparing deformation of wire thickness and width after final rolling, residual stress of the wire and the shape of the side part. The above study was conducted through LS-DYNA, a simulation program that can analyze material behavior of materials.
Intersecting holes deep inside a workpiece, are difficult to deburr because of poor accessibility. When holes are small and the intersecting angle (acute angle between hole axes) is less than 45°, difficulty is at its extreme. In this study, abrasive flow machining is used for a hole diameter of 3mm and intersecting angles of 30° and 45°. Tests were performed for AL6061 specimens, with process parameters allocated to L8(27) orthogonal array. Degree of deburring is strongly dependent on intersecting angle, abrasive grit size, and total volume of flow. Successful deburring was achieved for 30° intersecting angle.
High aspect ratio-arrayed micro structures are used in various fields such as semiconductor packaging, biochip, nano composite material and superhydrophobic surface. Micro electric discharge machining (MEDM) has an advantage, in that hard material can be easily removed regardless of mechanical properties of the material. Reverse micro electric discharge machining (REDM) can process various shapes and arrayed features. In this study, REDM was used for fabrication of a micro tool of eccentric shape, and was assisted with vibration to improve machining efficiency. The bored plate made of brass, was prepared as a tool for REDM. Because of the shape of the tool, concentration of debris occurs and increases machining time. The effect of vibration-assisted MEDM on emission of debris and machining time was described for the range of 2 - 6 μm amplitudes and of 100 - 900 Hz frequencies. As a result, vibration applied on machining reduces approximately 55% of machining time.
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Micro Hole Machining Characteristics of Glassy Carbon Using Electrical Discharge Machining (EDM) Jae Yeon Kim, Ji Hyo Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2025; 42(4): 325. CrossRef
Study on Micro Grooving of Tungsten Carbide Using Disk Tool Min Ki Kim, Chan Young Yang, Dae Bo Sim, Ji Hyo Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2024; 41(2): 123. CrossRef
Machining Characteristics of Micro EDM of Silicon Carbide Ju Hyeon Lee, Chan Young Yang, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2024; 41(2): 131. CrossRef
Micro Drilling of Single Crystal SiC Using Polycrystalline Diamond Tool Ui Seok Lee, Chan Young Yang, Ju Hyeon Lee, Bo Hyun Kim Journal of the Korean Society for Precision Engineering.2021; 38(7): 471. CrossRef
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Finite element analysis of CMP process was studied to understand uneven pressure distribution between polishing pad and wafer. Since WIWNU (Within wafer non-uniformity) is mainly influenced by dynamic viscoelastic properties of CMP polishing pad, the dynamic property of the polishing pad has to be understood first for dynamic finite element analysis of the process. To measure viscoelasticity of the polishing pad, time-dependent strain data by load were obtained using a viscoelasticity measurement system capable of measuring deformation by periodic load. Primary and secondary elastic modulus and relaxation time could be achieved for the behavior of the polishing pad by load. Finite element analysis was carried out under the same conditions as viscoelastic measurement. Material properties of the polishing pad were assumed based on results of experiments. By comparing experimental results with analytical results, material properties in the analytical model were modified and FEA was carried out again. It was confirmed that the behavior of the polishing pad by load in the experiment and FEA according to modified material properties were well matched. Through this process, viscoelastic properties of polishing pad were well defined for dynamic analysis of CMP process.
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High precision fabrication of aluminum optics by optimizing an Ar+ ion beam figuring strategy for polishing the contamination layer Chunyang Du, Yifan Dai, Chaoliang Guan, Hao Hu Optics Express.2021; 29(18): 28886. CrossRef
This paper proposes a practical method, for evaluating positioning of outdoor mobile robots using Unscented Kalman Filter (UKF). Since the UKF method does not require the linearization process unlike EKF localization, it can minimize effects of errors caused by linearization of non-linear models for position estimation. This method enables relatively high performance position estimation, using only non-inertial sensors such as low-precision GPS and a digital compass. Effectiveness of the UKF localization method was verified through actual experiments and performance of position estimation was compared with that of the existing EKF method. Experimental results revealed the proposed method has better performance than the EKF method, and it is stable regardless of initial error size, and observation period.
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Localization-based waiter robot for dynamic environment using Internet of Things Muhammad Waqas Qaisar, Muhammad Mudassir Shakeel, Krzysztof Kędzia, José Mendes Machado, Ahmed Zubair Jan International Journal of Information Technology.2025; 17(6): 3675. CrossRef
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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
The Smart Factory Equipment Engineering System collects and monitors necessary information in real-time. While putting the product into the equipment, operation conditions are lowered through a Recipe Management System. The working conditions are set by Run-to-Run a system for real-time detection and control through Fault Detection Classification function. In this study, the smart factory equipment system associated with the entire system is proposed by defining and integrating the necessary equipment management functions from a smart factory’s point of view. To do this, detailed analysis and process improvement on products, processes, and production line equipment were conducted and implemented in the smart factory equipment engineering system. The models proposed in this paper have been implemented to the production site of BGA-PCB. It has been confirmed that the models have resulted in significant change, and have qualitative and quantitative impacts on the working methods of equipment. Typically, data collection time, data entry time, and manual writing sheets were greatly reduced.
The importance of environmentally-friendly energy production has been growing globally, and studies on energy storage technologies are underway, to supply produced energy to consumers. Flywheel Energy Storage System (FESS) is physical energy storage technology, that stores generated electric energy into kinetic energy in the rotor. To design the FESS with a high-strength steel rotor, that is inexpensive, recyclable and easy to manufacture, mechanical and electrical components such as a rotor, bearings, etc. are required. Among these, safety of rotor and bearings is critical, because the rotor with high rotating speed may cause axis failure or fracture of the rotating body. Proper size of a rotor for required energy storage and radial, axial forces generated by the spinning rotor was calculated, considering gyroscopic forces acting on the rotating body. Based on the calculation, adequately sustainable angular ball bearings were selected. As a result, by conducting structural, modal and critical speed analysis, safety verification is presented pursuant to the American Petroleum Institute (API) publication 684.
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An Analytical Study on the Design of Housing Components for 10 kWh Flywheel Energy Storage System Deuk Kyu Lee, Beom Soo Kang Journal of the Korean Society for Precision Engineering.2020; 37(1): 59. CrossRef
The ball screw can be included in steering systems, the brake system, seat moving devices, and transmission systems of vehicles. Performance of the ball screw in these systems plays a key role in delivering agile and accurate power transmission. The purpose of this study is to improve performance by focusing on performance of the ball screw, by applying various conditions based on a design factor in the circulation system. The selected single design factor is to apply the cycloid curve to a circulation area. The circulation part to obtain a cycloid curve with highest performance, can have the smoothest ball flow. In addition, based on results, we intend to reduce failure cost that may be incurred in developing future ball screws for automobiles, and to establish databases that can be applied to developed products by deriving optimal shape.
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