• Title/Summary/Keyword: Manufacturing pressure

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Development of Variable Rolling Pressure Device for Bead-Shape Accuracy and Mechanical Property Enhancement in WAAM (Wire Arc Additive Manufacturing(WAAM)에서 적층 비드(Bead) 형상 정확도 및 기계적 특성 향상을 위한 가변 가압장치 개발)

  • Hwang, Ye-Han;Lee, Choon-Man;Kim, Dong-Hyeon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.8
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    • pp.66-71
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    • 2022
  • Metal additive manufacturing (AM) has revolutionized several manufacturing industries. AM can generate large-scale metal components and produce complex geometries close to net-shapes. WAAM is an AM technology that has garnered considerable interest among industries owing to its economics and relatively high deposition rates. However, the heat accumulation in the weld bead during deposition triggers distortion and residual stress. To address these problems, various methods of interpass pressure rolling systems have been suggested in recent research. In addition, combining the rolling and WAAM processes can mitigate residual stresses. The constant-pressure rolling of the interlayer also affect the microstructure. The coarse microstructure of the as-deposited sample was altered to finer equiaxed grains via these methods. However, the bead-shape accuracy of the interlayer constant-pressure method does not consider the heat accumulation in each layer. Therefore, this study develops an interpass variable pressure rolling system that considers the heat accumulation of each layer. The interpass variable pressure rolling system comprises deposition, detection, pressure, and transport units. Finally, verification tests are performed on the interpass variable-pressure rolling system (at 500 kg) with the WAAM process, and the obtained results are discussed.

Optimization of Manufacturing Conditions of Pressure-Sensitive Ink Based on MWCNTs (MWCNTs 기반 인쇄형 압력감응잉크의 제조 조건 최적화)

  • Park, Sung-Chul;Lee, In-Hwan;Bae, Yong-Hwan;Kim, Ho-chan
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.8
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    • pp.1-7
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    • 2019
  • Materials that can be used for 3D printing have been developed in terms of phase and functionality. Materials should also be easily printed with high accuracy. In recent years, the concept of 4D printing has been extended to materials whose physical properties such as shape or volume can change depending on the environment. Typically, such high-performance 3D printing materials include bio-inks and inks for sensors. This study deals with the optimization of the manufacturing method to improve the functional properties of the pressure sensitive material, which can be used as a sensor based on change of the resistance according to the pressure. Specifically, the number of milling for dispersion, the ratio of hardener for controlling elasticity, and the content of MWCNTs were optimized. As a result, a method of manufacturing a highly sensitive pressure-sensitive ink capable of use in 3D printing was introduced.

Development of Atmospheric Pressure Plasma Equipment and It's Application to Flip Chip BGA Manufacturing Process (대기압 플라즈마 설비 개발 및 Flip Chip BGA 제조공정 적용)

  • Lee, Ki-Seok;Ryu, Sun-Joong
    • Journal of the Semiconductor & Display Technology
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    • v.8 no.2
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    • pp.15-21
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    • 2009
  • Atmospheric pressure plasma equipment was successfully applied to the flip chip BGA manufacturing process to improve the uniformity of flux printing process. The problem was characterized as shrinkage of the printed flux layer due to insufficient surface energy of the flip chip BGA substrate. To improve the hydrophilic characteristics of the flip chip BGA substrate, remote DBD type atmospheric pressure plasma equipment was developed and adapted to the flux print process. The equipment enhanced the surface energy of the substrate to reasonable level and made the flux be distributed over the entire flip chip BGA substrate uniformly. This research was the first adaptation of the atmospheric pressure plasma equipment to the flip chip BGA manufacturing process and a lot of possible applications are supposed to be extended to other PCB manufacturing processes such as organic cleaning, etc.

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Manufacturing and Performance Test of Obsolete Valve in NPP using DED Metal 3D Printing Technology (원전 단종 밸브의 DED 방식 금속 3D프린팅 제작 및 성능시험)

  • Kyungnam Jang
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.17 no.2
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    • pp.75-82
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    • 2021
  • The 3D printing technology is one of the fourth industrial revolution technology that drives innovation in the manufacturing process, and should be applied to nuclear industry for various purposes according to the manufacturing trend change. In nuclear industry, it can be applied to manufacture obsolete items and new designed parts in advanced reactors or small modular reactors (SMRs), replacing the traditional manufacturing technologies. A gate valve body was manufactured, which was obsolete in nuclear power plant, using DED(Directed Energy Deposition) metal 3D printing technology after restoring design characteristics including 3D design drawing by reverse engineering. The 3D printed valve body was assembled with commercial parts such as seat-ring, disk, stem, and actuator for performance test. For the valve assembly, including 3D printed valve body, several tests were performed, including pressure test, end-loading test, and seismic test according to KEPIC MGG and KEPIC MFC. In the pressure test, hydraulic pressure of 391kgf/cm2 was applied to 3D printed valve body, and no leak was detected. Also the 3D printed valve assembly was performed well in end-loading and seismic tests.

The Trial Manufacturing of Inner Bulb of 200W High Pressure Mercurry Lamps (고압수은램프발광관의 시작연구)

  • Chol Kon Chee
    • 전기의세계
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    • v.19 no.2
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    • pp.18-20
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    • 1970
  • Research on the domestic production of arc tube of high pressure mercury lamp. This research is to solve the problem on the domestic manufacturing method for the arc tube of high pressure mercury lamp. (200W). The trial product is favorably compared with its foreign equivalents in its performances and quality. An advancement in manufacturing technology and the strict selection of raw materials will assure its domestification.

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Development trend of material and manufacturing process for fossil power generation (화력발전 소재 및 제조기술 개발)

  • Lee, Kyongwoon;Kong, Byeongook;Kim, Minsoo;Kang, Chung Yun
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.12 no.1
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    • pp.141-148
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    • 2016
  • This paper presents an overview of worldwide electric power development and National $700^{\circ}C$ Hyper Supercritical coal-fired power generation(HSC) focus on materials and manufacturing process. To Increase the efficiency of electric power generation, It is necessary to increase steam temperature and pressure. In that case, New material and manufacturing process shall be developed for boiler and turbine component in high temperature and pressure operating condition. Therefore, Much Efforts in worldwide are progressing to develop materials and manufacturing technology and to build and operate an HSC.

Design of the Air Pressure Pick-up Head for Non-Contact Wafer Gripper (비접촉식 웨이퍼 그리퍼용 공압 파지식 헤드 설계)

  • Kim, Joon-Hyun
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.3
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    • pp.401-407
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    • 2012
  • The recent manufacturing process in the thin wafers and flat panel necessitate new approaches to reduce handling fragile and surface-sensitive damage of components. This paper presents a new pneumatic levitation for non-contact handling of parts and substrates. This levitation can achieve non-contact handling by blowing air into an air pressure pick-up head with radial passages to generate a negative pressure region. Negative pressure is caused by the radial air flow by nozzle throat and through holes connecting to the bottom region. The numerical analysis deals with the levitational motion with different design factors. The dynamic motion is examined in terms of force balance(dynamic equilibrium) occurring to the flow field between two objects. The stable equilibrium position and the safe separation distance are determined by analyzing the local pressure distribution in the fluid motion. They make considerable design factors consisting the air pressure pick-up head. As a result, in case that the safe separation distance is beyond 0.7mm, the proposed pick-up head can levitate stably at the equilibrium position. Furthermore, it can provide little effect of torque, and obtain more wide picking region according to the head size.

The inelastic buckling of varying thickness circular cylinders under external hydrostatic pressure

  • Ross, C.T.F.;Gill-Carson, A.;Little, A.P.F.
    • Structural Engineering and Mechanics
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    • v.9 no.1
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    • pp.51-68
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    • 2000
  • The paper presents theoretical and experimental investigations on three varying thickness circular cylinders, which were tested to destruction under external hydrostatic pressure. The five buckling theories that were presented were based on inelastic shell instability. Three of these inelastic buckling theories adopted the finite element method and the other two theories were based on a modified version of the much simpler von Mises theory. Comparison between experiment and theory showed that one of the inelastic buckling theories that was based on the von Mises buckling pressure gave very good results while the two finite element solutions, obtained by dividing the theoretical elastic instability pressures by experimentally determined plastic knockdown factors gave poor results. The third finite element solution which was based on material and geometrical non-linearity gave excellent results. Electrical resistance strain gauges were used to monitor the collapse mechanisms and these revealed that collapse occurred in the regions of the highest values of hoop stress, where considerable deformation took place.

Manufacture of Apparatus for Coolant Mix Performance Test (냉각제 혼합성능 시험용 장치의 제작)

  • Ku, Hyoun-Kon;Bae, Young-Gwan;Kim, Jin-Hee
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.2
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    • pp.73-78
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    • 2022
  • The test apparatus that can be protected from the high-temperature combustion flame and coolant injection was successfully manufactured. In this study, the coolant-injection module had a controllable consistent pressure, and the entire combustion module was protected using a nonflammable composite liner. Every flange was designed in accordance with the DIN standard, and the entire body of the module was designed in accordance with the EN 13445 code. Additionally, the hydraulic pressure test was performed in accordance with the 2014/68/EU directive and EN 13445 standard. Finally, after manufacturing, performance tests (such as pressure tests) were conducted to verify the reliability and safety.

Manufacturing Integral Safety Vents in Prismatic Lithium-ion Batteries (직사각형 리튬 이온 전지의 일체형 안전장치 제조 공정에 관한 연구)

  • Kim, J. H.;Lee, K. H.;Lim, Y. J.;Kim, B. M.
    • Transactions of Materials Processing
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    • v.24 no.4
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    • pp.293-298
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    • 2015
  • A safety vent is crucial to protect its user from unpredictable explosions caused by increasing internal pressure of the lithium-ion batteries. In order to prevent the explosion of the battery, a safety vent rupture is required when the internal pressure reaches a critical value. In conventional manufacturing, the cap plate and the safety vent are fabricated separately and subsequently welded to each other. In the current study, a manufacturing process including a backward extrusion and coining process is suggested to produce an integral safety vent which also has the benefit of increasing production efficiency. FE simulations were conducted to predict the rupture pressure and to design the safety vent using a ductile fracture criterion and the element deletion method. The critical value, C, in the ductile fracture criterion was obtained from uniaxial tensile tests with an annealed sheet of 1050-H14 aluminum alloy. Rupture tests were preformed to measure the rupture pressure of the safety vent. The results met the required rupture pressure within 8.5±0.5 kgf/cm2. The simulation results were compared with experimental results, which showed that the predicted rupture pressures are in good agreement with experimentally measured ones with a maximum error of only 3.9%.